Tektronix Series 2281 Precision DC Supply,Battery Simulator Reference manual

Model 2281S-20-6 Precision DC
Power Supply and Battery Simulator

Reference Manual

077114601 / March 2019

tek.com/keithley

*P077114601*

077114601

DC Power Supply and Battery Simulator

Model 2281S-20-6

Reference Manual

© 2019, Keithley Instruments, LLC

Cleveland, Ohio, U.S.A.

All rights reserved.

Any unauthorized reproduction, photocopy, or use of the information herein, in whole or in part,

without the prior written approval of Keithley Instruments, LLC, is strictly prohibited.

These are the original instructions in English.

All Keithley Instruments product names are trademarks or registered trademarks of Keithley

Instruments, LLC. Other brand names are trademarks or registered trademarks of their respective

holders.

Microsoft, Visual C++, Excel, and Windows are either registered trademarks or trademarks of

Microsoft Corporation in the United States and/or other countries.

Document number: 077114601 / March 2019

Safety precautions

The following safety precautions should be observed before using this product and any associated instrumentation. Although
some instruments and accessories would normally be used with nonhazardous voltages, there are situations where hazardous
conditions may be present.

This product is intended for use by personnel who recognize shock hazards and are familiar with the safety precautions required
to avoid possible injury. Read and follow all installation, operation, and maintenance information carefully before using the
product. Refer to the user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired.
The types of product users are:

Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring that the
equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.

Operators use the product for its intended function. They must be trained in electrical safety procedures and proper use of the
instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel perform routine procedures on the product to keep it operating properly, for example, setting the line
voltage or replacing consumable materials. Maintenance procedures are described in the user documentation. The procedures
explicitly state if the operator may perform them. Otherwise, they should be performed only by service personnel.

Service personnel are trained to work on live circuits, perform safe installations, and repair products. Only properly trained
service personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that are measurement, control, and data I/O connections, with low
transient overvoltages, and must not be directly connected to mains voltage or to voltage sources with high transient
overvoltages. Measurement Category II (as referenced in IEC 60664) connections require protection for high transient
overvoltages often associated with local AC mains connections. Certain Keithley measuring instruments may be connected to
mains. These instruments will be marked as category II or higher.

Unless explicitly allowed in the specifications, operating manual, and instrument labels, do not connect any instrument to mains.
Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test

fixtures. The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than
30 V RMS, 42.4 V peak, or 60 VDC are present. A good safety practice is to expect that hazardous voltage is present in any
unknown circuit before measuring.

Operators of this product must be protected from electric shock at all times. The responsible body must ensure that operators
are prevented access and/or insulated from every connection point. In some cases, connections must be exposed to potential
human contact. Product operators in these circumstances must be trained to protect themselves from the risk of electric shock. If
the circuit is capable of operating at or above 1000 V, no conductive part of the circuit may be exposed.

Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-limited
sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective
devices to limit fault current and voltage to the card.

Before operating an instrument, ensure that the line cord is connected to a properly-grounded power receptacle. Inspect the
connecting cables, test leads, and jumpers for possible wear, cracks, or breaks before each use.

When installing equipment where access to the main power cord is restricted, such as rack mounting, a separate main input
power disconnect device must be provided in close proximity to the equipment and within easy reach of the operator.

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under
test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting
cables or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.

Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth)
ground. Always make measurements with dry hands while standing on a dry, insulated surface capable of withstanding the
voltage being measured.

For safety, instruments and accessories must be used in accordance with the operating instructions. If the instruments or
accessories are used in a manner not specified in the operating instructions, the protection provided by the equipment may be
impaired.

Do not exceed the maximum signal levels of the instruments and accessories. Maximum signal levels are defined in the
specifications and operating information and shown on the instrument panels, test fixture panels, and switching cards.

When fuses are used in a product, replace with the same type and rating for continued protection against fire hazard.
Chassis connections must only be used as shield connections for measuring circuits, NOT as protective earth (safety ground)

connections.
If you are using a test fixture, keep the lid closed while power is applied to the device under test. Safe operation requires the use

of a lid interlock.

If a screw is present, connect it to protective earth (safety ground) using the wire recommended in the user documentation.

The symbol on an instrument means caution, risk of hazard. The user must refer to the operating instructions located in the
user documentation in all cases where the symbol is marked on the instrument.

The symbol on an instrument means warning, risk of electric shock. Use standard safety precautions to avoid personal
contact with these voltages.

The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns.

The symbol indicates a connection terminal to the equipment frame.

If this symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be
properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains hazards that might result in personal injury or death. Always read
the associated information very carefully before performing the indicated procedure.

The CAUTION heading in the user documentation explains hazards that could damage the instrument. Such damage may
invalidate the warranty.

The CAUTION heading with the symbol in the user documentation explains hazards that could result in moderate or minor
injury or damage the instrument. Always read the associated information very carefully before performing the indicated
procedure. Damage to the instrument may invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.
Before performing any maintenance, disconnect the line cord and all test cables.
To maintain protection from electric shock and fire, replacement components in mains circuits — including the power

transformer, test leads, and input jacks — must be purchased from Keithley. Standard fuses with applicable national safety
approvals may be used if the rating and type are the same. The detachable mains power cord provided with the instrument may
only be replaced with a similarly rated power cord. Other components that are not safety-related may be purchased from other
suppliers as long as they are equivalent to the original component (note that selected parts should be purchased only through
Keithley to maintain accuracy and functionality of the product). If you are unsure about the applicability of a replacement
component, call a Keithley office for information.

Unless otherwise noted in product-specific literature, Keithley instruments are designed to operate indoors only, in the following
environment: Altitude at or below 2,000 m (6,562 ft); temperature 0 °C to 50 °C (32 °F to 122 °F); and pollution degree 1 or 2.

To clean an instrument, use a cloth dampened with deionized water or mild, water-based cleaner. Clean the exterior of the
instrument only. Do not apply cleaner directly to the instrument or allow liquids to enter or spill on the instrument. Products that
consist of a circuit board with no case or chassis (e.g., a data acquisition board for installation into a computer) should never
require cleaning if handled according to instructions. If the board becomes contaminated and operation is affected, the board
should be returned to the factory for proper cleaning/servicing.

Safety precaution revision as of June 2017.

Introduction .............................................................................................................. 1-1

Table of contents

Welcome .............................................................................................................................. 1-1

Extended warranty ............................................................................................................... 1-1

Contact information .............................................................................................................. 1-2

Product documentation and drivers ..................................................................................... 1-2

Organization of manual sections .......................................................................................... 1-3

Key features ......................................................................................................................... 1-4

Standard accessories ........................................................................................................... 1-5

Optional accessories ............................................................................................................ 1-6

Available services ................................................................................................................ 1-6

General ratings ..................................................................................................................... 1-7

Terminology in this manual .................................................................................................. 1-7

General operation .................................................................................................... 2-1

Front-panel overview ............................................................................................................ 2-1

Rear-panel overview ............................................................................................................ 2-3

Front-panel user interface .................................................................................................... 2-4

Startup screen ........................................................................................................................... 2-4

Home screens ........................................................................................................................... 2-4

Power supply menu overview.................................................................................................. 2-19

Battery test menu overview ..................................................................................................... 2-32

Battery simulator menu overview ............................................................................................ 2-42

Adjusting the backlight brightness and timer ........................................................................... 2-51

Installing the system ........................................................................................................... 2-52

Bumpers .................................................................................................................................. 2-52

Dimensions ............................................................................................................................. 2-53

Power the instrument on and off ............................................................................................. 2-58

Test connections ................................................................................................................ 2-61

Front-panel connector ............................................................................................................. 2-62

Rear-panel output mating connector ....................................................................................... 2-63

Two-wire local sense connection ............................................................................................ 2-63

Four-wire sense connection .................................................................................................... 2-64

Open leads detection .............................................................................................................. 2-66

Reversed sense leads ............................................................................................................. 2-67

Remote communications interfaces ................................................................................... 2-68

Supported remote interfaces ................................................................................................... 2-69

GPIB communications ............................................................................................................. 2-69

LAN communications .............................................................................................................. 2-72

USB communications .............................................................................................................. 2-88

How to install the Keithley I/O Layer ....................................................................................... 2-92

Set voltage and current limit .............................................................................................. 2-93

Constant voltage (CV) and constant current (CC) mode ......................................................... 2-94

Select a measurement function ......................................................................................... 2-96

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

Power supply ........................................................................................................................... 2-96

Battery test .............................................................................................................................. 2-97

Battery simulator ..................................................................................................................... 2-97

Select a specific measurement range ................................................................................ 2-97

Selecting a specific measurement range ................................................................................ 2-98

Using autoranging for current measurements ......................................................................... 2-99

Protection ......................................................................................................................... 2-100

Overvoltage protection .......................................................................................................... 2-101

Overcurrent protection .......................................................................................................... 2-102

Overtemperature protection .................................................................................................. 2-103

Overprotection error .............................................................................................................. 2-103

Maximum voltage limits ......................................................................................................... 2-104

Saving setups ................................................................................................................... 2-105

Save a user setup ................................................................................................................. 2-105

Recall a user setup ............................................................................................................... 2-106

Specify a default setup .......................................................................................................... 2-107

Using the event log .......................................................................................................... 2-107

Information provided for each event log entry ....................................................................... 2-107

Save the event log to an external flash drive ........................................................................ 2-108

Clear the event log ................................................................................................................ 2-108

System information .......................................................................................................... 2-108

Instrument sounds ............................................................................................................ 2-109

Resets .............................................................................................................................. 2-109

Reset the instrument ............................................................................................................. 2-110

Reset default values .............................................................................................................. 2-110

Functions and features ............................................................................................ 3-1

Instrument access ................................................................................................................ 3-1

Changing the instrument access mode ..................................................................................... 3-2

Changing the password ............................................................................................................ 3-2

Graph ................................................................................................................................... 3-3

Changing the window position and zoom .................................................................................. 3-3

Adjusting the scale and offset of the Y-axis .............................................................................. 3-4

Graphing the battery test function ............................................................................................. 3-6

Graphing the battery simulation function ................................................................................... 3-7

Output delay, slew rate, and source delay ........................................................................... 3-8

Output delay .............................................................................................................................. 3-8

Slew rate ................................ ................................................................ ................................... 3-9

Source delay ........................................................................................................................... 3-10

Data buffer ......................................................................................................................... 3-11

Effects of reset and power cycle on buffer .............................................................................. 3-11

Buffer fill status ........................................................................................................................ 3-12

Setting reading buffer size and buffer mode............................................................................ 3-12

Viewing and saving buffer content .......................................................................................... 3-14

Configuring the statistics applied to data in the buffer ............................................................. 3-18

Clearing the buffer ................................................................................................................... 3-21

Automatically clearing a buffer ................................................................................................ 3-21

Digital I/O ........................................................................................................................... 3-22

Digital I/O port ......................................................................................................................... 3-22

Configuring digital I/O lines ..................................................................................................... 3-27

Trigger model ..................................................................................................................... 3-30

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents

Idle and initiate ........................................................................................................................ 3-31

Arm layer ................................................................................................................................. 3-31

Trigger layer ............................................................................................................................ 3-31

Source, source delay, and measure actions ........................................................................... 3-32

Counter ................................................................................................................................... 3-32

Meter complete ....................................................................................................................... 3-32

Running the trigger model ....................................................................................................... 3-33

Level trigger ....................................................................................................................... 3-35

Configuring a voltage level trigger ........................................................................................... 3-35

Configuring a current level trigger ........................................................................................... 3-37

List operation ...................................................................................................................... 3-39

Configuring a list ..................................................................................................................... 3-40

Importing a list from an external USB flash drive .................................................................... 3-42

Exporting a list to an external USB flash drive ........................................................................ 3-43

Configuring and running a list.................................................................................................. 3-43

Aborting a list .......................................................................................................................... 3-53

Sink operation .................................................................................................................... 3-54

Battery test ......................................................................................................................... 3-55

Battery charging and discharging ............................................................................................ 3-56

Battery discharging test ........................................................................................................... 3-57

Battery charging test ............................................................................................................... 3-59

Generating and editing a battery model .................................................................................. 3-60

ESR measurement .................................................................................................................. 3-63

A-H measurement ................................................................................................................... 3-66

Capacitance measurement ..................................................................................................... 3-69

Battery simulation ............................................................................................................... 3-70

Battery simulation settings ...................................................................................................... 3-70

Simulating a battery ................................................................................................................ 3-71

Measurement optimization ...................................................................................... 4-1

Introduction .......................................................................................................................... 4-1

Optimizing either measurement accuracy or speed ............................................................ 4-1

Resolution ................................................................................................................................. 4-2

NPLC ........................................................................................................................................ 4-4

Autozero measurements ........................................................................................................... 4-5

Displayed digits ......................................................................................................................... 4-6

Filtering measurement data....................................................................................................... 4-7

Math calculations that you can apply to measurements .................................................... 4-11

mx+b ....................................................................................................................................... 4-11

Setting mx+b math operations ................................................................................................ 4-12

Relative offset .................................................................................................................... 4-13

Establishing a relative offset value .......................................................................................... 4-13

Displayed measurements................................................................................................... 4-15

Select the source of readings .................................................................................................. 4-17

ESR measurement ............................................................................................................. 4-18

Introduction to the ESR measurement .................................................................................... 4-18

Measuring ESR in the battery test function ............................................................................. 4-20

A-H measurement .............................................................................................................. 4-21

Introduction to the A-H measurement ..................................................................................... 4-21

Measuring A-H in the battery test function .............................................................................. 4-22

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

Application examples .............................................................................................. 5-1

Simple voltage output and current measurement ................................................................ 5-1

Equipment required ................................................................................................................... 5-1

Set up remote communications ................................................................................................. 5-1

Device connections ................................................................................................................... 5-2

Set the voltage and current limit ................................................................................................ 5-2

Configure and execute a 10-step linear list sweep .............................................................. 5-3

Equipment required ................................................................................................................... 5-3

Set up remote communications ................................................................................................. 5-4

Device connections ................................................................................................................... 5-4

Configure a 10-step linear list sweep ........................................................................................ 5-4

Execute a 10-step linear list sweep ........................................................................................... 5-6

Perform a fast current load measurement ........................................................................... 5-7

Equipment required ................................................................................................................... 5-7

Set up remote communications ................................................................................................. 5-8

Device connections ................................................................................................................... 5-8

Measure the fast current load changes ................................................................................... 5-10

Battery test ......................................................................................................................... 5-13

Equipment required ................................................................................................................. 5-13

Device connections ................................................................................................................. 5-13

Test a battery and generate a battery model........................................................................... 5-13

Battery simulation test ........................................................................................................ 5-16

Equipment required ................................................................................................................. 5-16

Device connections ................................................................................................................. 5-16

Simulate a battery with the 2281S ........................................................................................... 5-17

Explanations of the test ........................................................................................................... 5-18

Introduction to SCPI commands ............................................................................. 6-1

Introduction to SCPI ............................................................................................................. 6-1

Command messages ................................................................................................................ 6-1

Command execution rules......................................................................................................... 6-2

SCPI command programming notes .................................................................................... 6-2

SCPI command formatting ........................................................................................................ 6-2

Using the SCPI command reference ......................................................................................... 6-5

SCPI command reference ........................................................................................ 7-1

Common commands ............................................................................................................ 7-1

*CLS .......................................................................................................................................... 7-2

*ESE ......................................................................................................................................... 7-3

*ESR? ....................................................................................................................................... 7-4

*IDN? ........................................................................................................................................ 7-4

*LANG? ..................................................................................................................................... 7-5

*OPC ......................................................................................................................................... 7-6

*RCL ......................................................................................................................................... 7-6

*RST ......................................................................................................................................... 7-7

*SAV ......................................................................................................................................... 7-7

*SRE ......................................................................................................................................... 7-8

*STB? ........................................................................................................................................ 7-9

*TRG ......................................................................................................................................... 7-9

*TST? ...................................................................................................................................... 7-10

*WAI ........................................................................................................................................ 7-10

:ABORt[n] ................................................................................................................................ 7-12

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents

:CONFigure[n]:<function> ....................................................................................................... 7-13

:ENTRy[n]:FUNCtion ............................................................................................................... 7-14

:FETCh[n]? .............................................................................................................................. 7-15

:FORCe:TRIGger .................................................................................................................... 7-16

:FORMat:ELEMents ................................................................................................................ 7-17

:MEASure[n]:<function>? ........................................................................................................ 7-18

:READ[n]? ............................................................................................................................... 7-20

ARM subsystem ................................................................................................................. 7-21

:ARM[:SEQuence[n]]:COUNt .................................................................................................. 7-21

:ARM[:SEQuence[n]]:SOURce ................................................................................................ 7-22

BATTery subsystem ........................................................................................................... 7-23

:BATTery[n]:DATA:CLEar ....................................................................................................... 7-23

:BATTery[n]:DATA:DATA? ...................................................................................................... 7-23

:BATTery[n]:DATA:DATA:SELected? ..................................................................................... 7-25

:BATTery[n]:DATA:SAVE ........................................................................................................ 7-26

:BATTery:DIGital:LINE<line_index>:CONFigure ..................................................................... 7-27

:BATTery:DIGital:LINE<n>:EDGe ........................................................................................... 7-28

:BATTery:DIGital:LINE<n>:MANual:INPut:DATA? .................................................................. 7-28

:BATTery[n]:MODel:LOAD:USB .............................................................................................. 7-29

:BATTery[n]:MODel<modelindex>:<element>......................................................................... 7-30

:BATTery[n]:MODel<modelindex>:<element>:APPend .......................................................... 7-31

:BATTery[n]:MODel<modelindex>:<element>:SIMPlify .......................................................... 7-32

:BATTery[n]:MODel<modelindex>:<element>:STEPs? .......................................................... 7-33

:BATTery[n]:MODel<modelindex>:ROW<rowindex> .............................................................. 7-34

:BATTery[n]:MODel:RCL ......................................................................................................... 7-35

:BATTery[n]:MODel:SAVE:INTernal ........................................................................................ 7-36

:BATTery[n]:MODel:SAVE:USB .............................................................................................. 7-37

:BATTery[n]:SIMulator:CAPacity? ........................................................................................... 7-37

:BATTery[n]:SIMulator:CAPacity:LIMit .................................................................................... 7-38

:BATTery[n]:SIMulator:CURRent? .......................................................................................... 7-39

:BATTery[n]:SIMulator:CURRent:LIMit .................................................................................... 7-39

:BATTery[n]:SIMulator:CURRent:PROTection[:LEVel] ........................................................... 7-40

:BATTery[n]:SIMulator:HV ....................................................................................................... 7-41

:BATTery[n]:SIMulator:LV ....................................................................................................... 7-42

:BATTery[n]:SIMulator:METHod .............................................................................................. 7-43

:BATTery[n]:SIMulator:RESistance? ....................................................................................... 7-44

:BATTery[n]:SIMulator:RESistance:OFFSet............................................................................ 7-44

:BATTery[n]:SIMulator:SAMPle:INTerval ................................................................................ 7-45

:BATTery[n]:SIMulator:SOC .................................................................................................... 7-46

:BATTery[n]:SIMulator:TVOLtage? ......................................................................................... 7-47

:BATTery[n]:SIMulator:TVOLtage:PROTection[:LEVel] .......................................................... 7-47

:BATTery[n]:SIMulator:VOC .................................................................................................... 7-48

:BATTery[n]:SIMulator:VOC:EMPTy ....................................................................................... 7-49

:BATTery[n]:SIMulator:VOC:FULL .......................................................................................... 7-50

:BATTery[n]:TEST:MEASure:EVOC? ..................................................................................... 7-51

:BATTery[n]:TEST:SENSe:AH:ESRInterval ............................................................................ 7-51

:BATTery[n]:TEST:SENSe:AH:EXECute................................................................................. 7-52

:BATTery[n]:TEST:SENSe:AH:GMODel:RANGe .................................................................... 7-52

:BATTery[n]:TEST:SENSe:AH:GMODel:SAVE:INTernal ........................................................ 7-53

:BATTery[n]:TEST:SENSe:AH:GMODel:SAVE:USB .............................................................. 7-54

:BATTery[n]:TEST:SENSe:AH:ILIMit ...................................................................................... 7-55

:BATTery[n]:TEST:SENSe:AH[:LEVel]? .................................................................................. 7-55

:BATTery[n]:TEST:SENSe:AH:VFULl ..................................................................................... 7-56

:BATTery[n]:TEST:SENSe:EVOC:DELAy ............................................................................... 7-56

:BATTery[n]:TEST:SENSe:SAMPle:INTerval .......................................................................... 7-57

:BATTery[n]:TEST[:SOURce]:CURRent:END ......................................................................... 7-58

:BATTery[n]:TEST[:SOURce]:CURRent:LIMit:SOURce .......................................................... 7-59

:BATTery[n]:TEST[:SOURce]:CURRent:PROTection[:LEVel]................................................. 7-60

:BATTery[n]:TEST[:SOURce]:HV ............................................................................................ 7-61

:BATTery[n]:TEST[:SOURce]:LV ............................................................................................ 7-62

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

:BATTery[n]:TEST[:SOURce]:VOLTage[:LEVel] ..................................................................... 7-63

:BATTery[n]:TEST[:SOURce]:VOLTage:LIMit ......................................................................... 7-64

:BATTery[n]:TEST[:SOURce]:VOLTage:PROTection[:LEVel]................................................. 7-65

:BATTery[n]:TRACe:TRIGger:CURRent:DIRection ................................................................. 7-66

:BATTery[n]:TRACe:TRIGger:CURRent[:LEVel] ..................................................................... 7-66

:BATTery[n]:TRACe:TRIGger:CURRent:STATe ..................................................................... 7-67

:BATTery[n]:TRACe:CLEar ..................................................................................................... 7-67

:BATTery[n]:TRACe:DATA? .................................................................................................... 7-68

:BATTery[n]:TRACe:DATA:SELected? ................................................................................... 7-70

:BATTery[n]:TRACe:SAVE ...................................................................................................... 7-71

:BATTery[n]:TRACe:TRIGger:OCCur? ................................................................................... 7-72

:BATTery[n]:TRACe:TRIGger:OFFSet .................................................................................... 7-72

:BATTery[n]:TRACe:TRIGger:VOLTage:DIRection ................................................................. 7-73

:BATTery[n]:TRACe:TRIGger:VOLTage[:LEVel] ..................................................................... 7-73

:BATTery[n]:TRACe:TRIGger:VOLTage:STATe ..................................................................... 7-74

:BATTery[n]:OUTPut:PROTection:CLEar ............................................................................... 7-74

:BATTery[n]:OUTPut:PROTection:TRIPped?.......................................................................... 7-75

:BATTery[n]:OUTPut[:STATe] ................................................................................................. 7-76

:BATTery[n]:STATus? ............................................................................................................. 7-76

CALCulate subsystem ........................................................................................................ 7-77

:CALCulate[1]:<function>:FORMat .......................................................................................... 7-77

:CALCulate[1]:<function>:KMATh:MBFactor ........................................................................... 7-78

:CALCulate[1]:<function>:KMATh:MMFactor .......................................................................... 7-79

:CALCulate[1]:<function>:KMATh:MUNits............................................................................... 7-80

:CALCulate[1]:<function>:STATe ............................................................................................ 7-81

:CALCulate2:DATA? ............................................................................................................... 7-82

:CALCulate2:FORMat ............................................................................................................. 7-84

:CALCulate2:FORMat:ELEMents ............................................................................................ 7-86

:CALCulate2:FUNCtion ........................................................................................................... 7-87

:CALCulate2:IMMediate .......................................................................................................... 7-88

:CALCulate2:STATe ................................................................................................................ 7-90

CALibration subsystem ...................................................................................................... 7-91

:CALibration:PROTected:CANCel ........................................................................................... 7-91

:CALibration:PROTected:CODE ............................................................................................. 7-92

:CALibration:PROTected:COUNt? .......................................................................................... 7-92

:CALibration:PROTected:DATA? ............................................................................................ 7-93

:CALibration:PROTected:DATE .............................................................................................. 7-93

:CALibration:PROTected[:DC[n]]:STEP<step> ....................................................................... 7-94

:CALibration:PROTected[:DC[n]]:STEP<step>:DATA ............................................................. 7-96

:CALibration:PROTected:SAVE .............................................................................................. 7-98

:CALibration:PROTected:STATe ............................................................................................. 7-99

Digital subsystem ............................................................................................................. 7-100

:DIGital:LINE<n>:FUNCtion .................................................................................................. 7-100

:DIGital:LINE<n>:MANual:INPut:DATA? ............................................................................... 7-101

DISPlay subsystem .......................................................................................................... 7-102

:DISPlay:BRIGhtness ............................................................................................................ 7-102

:DISPlay:CLEar ..................................................................................................................... 7-103

:DISPlay:SCREen ................................................................................................................. 7-103

:DISPlay:USER:TEXT[:DATA] ............................................................................................... 7-104

INITiate subsystem .......................................................................................................... 7-105

:INITiate[n]:CONTinuous ....................................................................................................... 7-105

:INITiate[n][:IMMediate] ......................................................................................................... 7-106

MMEMory subsystem ....................................................................................................... 7-106

:MMEMory:LOAD:SETup ................................................................ ...................................... 7-106

:MMEMory:SAVE:SETup ...................................................................................................... 7-107

OUTPut subsystem .......................................................................................................... 7-108

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents

:OUTPut:DELay:FALLing ...................................................................................................... 7-108

:OUTPut:DELay:RISing ......................................................................................................... 7-109

:OUTPut:DELay:STATe ........................................................................................................ 7-110

:OUTPut:PROTection:CLEar................................................................................................. 7-111

:OUTPut:PROTection:TRIPped?[<channel>] ........................................................................ 7-112

:OUTPut[:STATe] .................................................................................................................. 7-113

SENSe subsystem ........................................................................................................... 7-114

:SENSe[n]:FUNCtion ............................................................................................................. 7-114

:SENSe[n]:<function>:AVERage:COUNt .............................................................................. 7-115

:SENSe[n]:<function>:AVERage[:STATe] ............................................................................. 7-116

:SENSe[n]:<function>:AVERage:TCONtrol ........................................................................... 7-117

:SENSe[n]:<function>:AVERage:WINDow ............................................................................ 7-118

:SENSe[n]:<function>:DIGits ................................................................................................. 7-119

:SENSe[n]:<function>:NPLCycles ......................................................................................... 7-120

:SENSe[n]:<function>:RANGe .............................................................................................. 7-121

:SENSe[n]:<function>:RANGe:AUTO ................................................................................... 7-122

:SENSe[n]:<function>:REFerence ......................................................................................... 7-123

:SENSe[n]:<function>:REFerence:ACQuire .......................................................................... 7-124

:SENSe[n]:<function>:REFerence:STATe ............................................................................ 7-125

:SENSe[n]:<function>:RESolution ......................................................................................... 7-126

SOURce subsystem ......................................................................................................... 7-127

[:SOURce[n]]:DELay ............................................................................................................. 7-127

[:SOURce[n]]:DELay:STATe ................................................................................................. 7-128

[:SOURce[n]]:<function>:PROTection[:LEVel] ...................................................................... 7-129

[:SOURce[n]]:<function>[:LEVel][:IMMediate][:AMPLitude] ................................................... 7-130

[:SOURce[n]]:VOLTage:LIMit[:AMPLitude] ........................................................................... 7-131

[:SOURce[n]]:VOLTage:SLEW:RISing .................................................................................. 7-132

[:SOURce[n]]:VOLTage:SLEW:FALLing ............................................................................... 7-133

[:SOURce[n]]:LIST<listNumber>:<element> ......................................................................... 7-134

[:SOURce[n]]:LIST<listNumber>:<element>:APPend ........................................................... 7-135

[:SOURce[n]]:LIST<listNumber>:<element>:POINts? ........................................................... 7-136

[:SOURce[n]]:LIST:END:ZERO ............................................................................................. 7-137

[:SOURce[n]]:LIST:HTIMe ..................................................................................................... 7-137

[:SOURce[n]]:LIST:LOAD:USB ............................................................................................. 7-138

[:SOURce[n]]:LIST:MCOMPlete ............................................................................................ 7-139

[:SOURce[n]]:LIST:RCL ........................................................................................................ 7-140

[:SOURce[n]]:LIST:SAVE:INTernal ....................................................................................... 7-143

[:SOURce[n]]:LIST:SAVE:USB .............................................................................................. 7-144

[:SOURce[n]]:LIST:STATe .................................................................................................... 7-145

STATus subsystem .......................................................................................................... 7-148

:STATus:MEASurement[:EVENt]? ........................................................................................ 7-148

:STATus:MEASurement:ENABle .......................................................................................... 7-148

:STATus:MEASurement:INSTrument[:EVENt]? .................................................................... 7-149

:STATus:MEASurement:INSTrument:ENABle ...................................................................... 7-149

:STATus:MEASurement:INSTrument:ISUMmary[:EVENt]? .................................................. 7-150

:STATus:MEASurement:INSTrument:ISUMmary:ENABle .................................................... 7-151

:STATus:MEASurement:INSTrument:ISUMmary:CONDition? .............................................. 7-152

:STATus:OPERation[:EVENt]? .............................................................................................. 7-152

:STATus:OPERation:ENABle ................................................................................................ 7-153

:STATus:OPERation:INSTrument[:EVENt]? ......................................................................... 7-153

:STATus:OPERation:INSTrument:ENABle ........................................................................... 7-154

:STATus:OPERation:INSTrument:ISUMmary[:EVENt]? ....................................................... 7-154

:STATus:OPERation:INSTrument:ISUMmary:ENABle .......................................................... 7-155

:STATus:OPERation:INSTrument:ISUMmary:CONDition? ................................................... 7-156

:STATus:PRESet .................................................................................................................. 7-156

:STATus:QUEStionable[:EVENt]? ......................................................................................... 7-157

:STATus:QUEStionable:ENABle ........................................................................................... 7-158

:STATus:QUEStionable:INSTrument[:EVENt]?..................................................................... 7-158

:STATus:QUEStionable:INSTrument:ENABle ....................................................................... 7-159

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

:STATus:QUEStionable:INSTrument:ISUMmary[:EVENt]? ................................................... 7-160

:STATus:QUEStionable:INSTrument:ISUMmary:ENABle ..................................................... 7-160

:STATus:QUEStionable:INSTrument:ISUMmary:CONDition? .............................................. 7-161

SYSTem subsystem ......................................................................................................... 7-162

:SYSTem:AZERo[n][:STATe] ................................................................................................ 7-162

:SYSTem:BEEPer:ERRor[:STATe] ....................................................................................... 7-163

:SYSTem:COMMunication:ABORt ........................................................................................ 7-163

:SYSTem:COMMunication:LAN:CONFigure ......................................................................... 7-164

:SYSTem:COMMunication:LAN:MACaddress? ..................................................................... 7-165

:SYSTem:DATE .................................................................................................................... 7-166

:SYSTem:ERRor? ................................................................................................................. 7-166

:SYSTem:ERRor:CLEar ........................................................................................................ 7-167

:SYSTem:ERRor:CODE? ...................................................................................................... 7-167

:SYSTem:ERRor:COUNt?..................................................................................................... 7-168

:SYSTem:EVENtlog:SAVE .................................................................................................... 7-168

:SYSTem:GPIB:ADDRess..................................................................................................... 7-169

:SYSTem:KCLick .................................................................................................................. 7-170

:SYSTem:LOCal .................................................................................................................... 7-170

:SYSTem:LFRequency? ....................................................................................................... 7-171

:SYSTem:PASSword:LOCK .................................................................................................. 7-171

:SYSTem:PASSword:MODE ................................................................................................. 7-172

:SYSTem:PASSword:NEW ................................................................................................... 7-173

:SYSTem:PASSword:UNLock ................................................................ ............................... 7-174

:SYSTem:POSetup:STATe ................................................................................................... 7-174

:SYSTem:PRESet ................................................................................................................. 7-175

:SYSTem:RWLock ................................................................................................................ 7-176

:SYSTem:TIME ..................................................................................................................... 7-176

:SYSTem:VERSion? ............................................................................................................. 7-177

TRACe subsystem ........................................................................................................... 7-177

:DATA[n]:CLEar .................................................................................................................... 7-177

:DATA[n]:CLEar:AUTO ......................................................................................................... 7-178

:DATA[n]:DATA? ................................................................................................................... 7-178

:DATA[n]:DATA:SELected?................................................................................................... 7-180

:DATA[n]:FEED ..................................................................................................................... 7-182

:DATA[n]:FEED:CONTrol ...................................................................................................... 7-183

:DATA[n]:POINts ................................................................................................................... 7-184

:DATA[n]:POINts:ACTual? .................................................................................................... 7-184

:DATA[n]:SAVE ..................................................................................................................... 7-185

:TRACe[n]:CLEar .................................................................................................................. 7-186

:TRACe[n]:CLEar:AUTO ....................................................................................................... 7-186

:TRACe[n]:DATA? ................................................................................................................. 7-187

:TRACe[n]:DATA:SELected? ................................................................................................ 7-188

:TRACe[n]:FEED ................................................................................................................... 7-190

:TRACe[n]:FEED:CONTrol .................................................................................................... 7-191

:TRACe[n]:POINts ................................................................................................................. 7-192

:TRACe[n]:POINts:ACTual? .................................................................................................. 7-192

:TRACe[n]:SAVE ................................................................................................................... 7-193

:TRACe[n]:TRIGger:CURRent:DIRection .............................................................................. 7-194

:TRACe[n]:TRIGger:CURRent[:LEVel] ............................................................................ 7-194

:TRACe[n]:TRIGger:CURRent:STATe .................................................................................. 7-195

:TRACe[n]:TRIGger:OCCur? ................................................................................................. 7-195

:TRACe[n]:TRIGger:OFFSet ................................................................................................. 7-196

:TRACe[n]:TRIGger:VOLTage:DIRection .............................................................................. 7-196

:TRACe[n]:TRIGger:VOLTage[:LEVel] .................................................................................. 7-197

:TRACe[n]:TRIGger:VOLTage:STATe .................................................................................. 7-197

TRIGger subsystem ......................................................................................................... 7-198

:TRIGger[:SEQuence[n]]:COUNt ........................................................................................... 7-198

:TRIGger[:SEQuence[n]]:SAMPle:COUNt ............................................................................. 7-199

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents

:TRIGger[:SEQuence[n]]:SOURce ........................................................................................ 7-200

Troubleshooting guide ............................................................................................ 8-1

Introduction .......................................................................................................................... 8-1

Contacting support ............................................................................................................... 8-1

What to do if the power supply does not turn on ................................................................. 8-2

LAN troubleshooting suggestions ........................................................................................ 8-3

Error summary ..................................................................................................................... 8-3

Next steps ................................................................................................................. 9-1

Additional 2281S information ............................................................................................... 9-1

Maintenance ............................................................................................................. A-1

Introduction .......................................................................................................................... A-1

Line fuse replacement .......................................................................................................... A-1

Upgrading the firmware ........................................................................................................ A-2

From the front panel .................................................................................................................. A-3

Perform DIN VDE 701 test ................................................................................................... A-4

Cleaning the front-panel display .......................................................................................... A-4

Verification ............................................................................................................... B-1

Overview .............................................................................................................................. B-1

Test record ........................................................................................................................... B-1

DC voltage setting accuracy with remote sense ........................................................................ B-3

DC voltage setting accuracy without remote sense ................................................................... B-4

DC voltage readback accuracy with remote sense ................................................................... B-5

DC voltage readback accuracy without remote sense .............................................................. B-6

DC voltage line regulation without remote sense ...................................................................... B-6

DC voltage load regulation without remote sense ..................................................................... B-6

DC overvoltage protection ......................................................................................................... B-7

Maximum continuous average sink current ............................................................................... B-7

Sink current readback accuracy (1 A range) ............................................................................. B-8

Sink current readback accuracy (10 mA range) ........................................................................ B-8

Sink current readback accuracy (100 mA range) ...................................................................... B-9

DC current accuracy ............................................................................................................... B-10

DC current readback accuracy (10 A range) ........................................................................... B-11

DC current readback accuracy (1 A range) ............................................................................. B-11

DC current readback accuracy (10 mA range) ........................................................................ B-12

DC current readback accuracy (100 mA range) ...................................................................... B-12

DC current line regulation........................................................................................................ B-13

DC current load regulation ...................................................................................................... B-13

DC overcurrent protection ....................................................................................................... B-13

Voltage noise at 20 MHz ......................................................................................................... B-14

Current noise at 20 MHz ......................................................................................................... B-14

Performance verification procedures ................................................................................. B-15

Performance verification conditions ........................................................................................ B-15

Required equipment ................................................................................................................ B-16

Check DC voltage setting readback accuracy with remote sense ........................................... B-16

Table of contents Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

Check DC voltage setting accuracy without remote sense ..................................................... B-19

Check DC voltage readback accuracy without remote sense ................................................. B-21

Check DC voltage line regulation ............................................................................................ B-23

Check DC voltage load regulation ........................................................................................... B-25

Check DC overvoltage protection ............................................................................................ B-26

Check sink current capability................................................................................................... B-27

Check sink current readback accuracy (1 A range) ................................................................. B-28

Check sink current readback accuracy (100 mA and 10 mA ranges) ...................................... B-30

Check DC current accuracy .................................................................................................... B-32

Check DC current readback accuracy (10 A and 1 A ranges) ................................................. B-34

Check DC current readback accuracy (100 mA and 10 mA ranges) ....................................... B-36

Check DC current line regulation ............................................................................................ B-38

Check DC current load regulation ........................................................................................... B-40

Check overcurrent protection .................................................................................................. B-41

Check voltage noise (20 MHz) ................................................................................................ B-42

Check current noise (20 MHz) ................................................................................................. B-44

Calibration and adjustment ..................................................................................... C-1

Overview .............................................................................................................................. C-1

Environmental conditions ..................................................................................................... C-1

Warmup period .......................................................................................................................... C-2

Line power................................................................................................................................. C-2

Calibration considerations .................................................................................................... C-2

Calibration cycle ........................................................................................................................ C-2

Required equipment .................................................................................................................. C-3

Characterization shunts ............................................................................................................ C-4

Calibration connection.......................................................................................................... C-6

Voltage calibration connections................................................................................................. C-7

Current calibration connections ................................................................................................. C-8

Sink current calibration connections ........................................................................................ C-11

Front-panel calibration procedure ...................................................................................... C-12

Voltage calibration ................................................................................................................... C-12

Low-current calibration ............................................................................................................ C-13

High-current calibration ........................................................................................................... C-15

Low-sink current calibration..................................................................................................... C-16

High-sink current calibration .................................................................................................... C-18

Saving calibration constants from the front panel.................................................................... C-19

Remote calibration procedure ............................................................................................ C-20

Remote voltage calibration ...................................................................................................... C-21

Remote low-current calibration ................................................................................................ C-22

Remote high-current calibration .............................................................................................. C-23

Remote low-sink current calibration ........................................................................................ C-25

Remote high-sink-current calibration ....................................................................................... C-27

Saving calibration constants using SCPI commands .............................................................. C-28

Configure the calibration date ................................................................................................. C-29

Exit the calibration procedure using SCPI commands ............................................................ C-29

Change the calibration password ....................................................................................... C-30

Calibration constants .......................................................................................................... C-31

Status model ............................................................................................................ D-1

Overview .............................................................................................................................. D-1

Status model structure .............................................................................................................. D-3

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Table of contents

Programming and reading registers ..................................................................................... D-5

Programming enable registers .................................................................................................. D-5

Reading the registers ................................................................................................................ D-6

Clearing the registers ........................................................................................................... D-6

Status byte and service request ........................................................................................... D-7

Status Byte Register ................................................................................................................. D-7

Service Request Enable Register ............................................................................................. D-8

Status register sets .............................................................................................................. D-9

Register bit descriptions ............................................................................................................ D-9

Event registers ........................................................................................................................ D-20

Event enable registers ............................................................................................................ D-20

Condition registers .................................................................................................................. D-20

Queues ............................................................................................................................... D-20

Output queue .......................................................................................................................... D-20

Error queue ............................................................................................................................. D-21

Serial polling and SRQ ....................................................................................................... D-21

Status model programming examples ............................................................................... D-22

SRQ when reading buffer becomes full ................................................................................... D-22

SRQ when trigger model is finished ........................................................................................ D-23

In this section:

Welcome ................................ ................................ .................. 1-1

Extended warranty ................................................................... 1-1

Contact information .................................................................. 1-2

Product documentation and drivers .......................................... 1-2

Organization of manual sections .............................................. 1-3

Key features ............................................................................. 1-4

Standard accessories ............................................................... 1-5

Optional accessories ................................................................ 1-6

Available services .................................................................... 1-6

General ratings ......................................................................... 1-7

Terminology in this manual ...................................................... 1-7

Section 1

Introduction

Welcome

Thank you for choosing a Keithley Instruments product. The 2281S Precision DC Power Supply and
Battery Simulator is a high-sensitivity, low-noise, programmable instrument that sources stable,
low-noise voltage and can monitor load currents over a wide dynamic range, from amperes to
nanoamperes.

In addition to serving as a power supply, it can conduct battery testing by charging and discharging
the battery under test and creating a model for the battery. The 2281S can also simulate batteries to
facilitate tests conducted on the products supplied by batteries.

The high-resolution, 4.3-inch TFT color display presents numerous parameters that describe the state
of the instrument to enable you to get the most information from your measurements.

Extended warranty

Additional years of warranty coverage are available on many products. These valuable contracts
protect you from unbudgeted service expenses and provide additional years of protection at a fraction
of the price of a repair. Extended warranties are available on new and existing products. Contact your
local Keithley Instruments office, sales partner, or distributor for details.

Section 1: Introduction Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

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Contact information

If you have any questions after you review the information in this documentation, please contact your
local Keithley Instruments office, sales partner, or distributor. You can also call the corporate
headquarters of Keithley Instruments (toll-free inside the U.S. and Canada only) at 1-800-935-5595,
or from outside the U.S. at [phone]. For worldwide contact numbers, visit the Keithley

Instruments website (tek.com/keithley).

Product documentation and drivers

The following documentation and drivers for the 2281S are available for download from the Keithley

Instruments support website (tek.com/support).

Quick Start Guide: Provides unpacking instructions, describes basic connections, reviews basic

operation information, and provides a quick test procedure to ensure the instrument is
operational.

Reference Manual: Includes advanced operation topics, maintenance information,

troubleshooting procedures, and in-depth descriptions of programming commands.

Accessories information: Documentation for accessories that are available for the 2281S.
Drivers and release notes: IVI Instrument Driver, National Instruments LabVIEW™ driver, and

related release notes.

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Section 1: Introduction

077114601 / March 2019 1-3

Organization of manual sections

The information in this manual is organized into the following major categories:

General operation: Describes the components of the instrument and basic operation.
Functions and features: Describes features and functions, such as measure operations, battery test,

battery simulation, list mode, reading buffers, triggering, the digital I/O port, graph function, output
delay, and slew rate.

Measurement optimization: Describes best practices and recommended procedures that can
increase measurement speed, accuracy, and sensitivity.

Application examples: Contains examples of several applications that you can use as a starting
point for your own application.

Introduction to SCPI commands: Describes how to control the instrument using SCPI commands.
SCPI command reference: Contains programming notes and an alphabetical listing of all SCPI

commands available for the 2281S.

Troubleshooting guide: Describes the event log and basic LAN troubleshooting.
Next steps: Contains sources of additional information.
Maintenance: Contains information about instrument maintenance, including line fuse replacement

and firmware upgrades.

Verification: Contains performance verification procedures.
Calibration and adjustment: Contains information about instrument calibration from the front panel

and using SCPI commands.
Status model: Describes the 2281S status model.

Section 1: Introduction Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

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Key features

Model

Description

2281S-20-6

Precision-measurement DC power supply, 20 V, 6 A

The 2281S has three basic functions: High-performance power supply, battery test, and battery
simulation.

As a high-performance power supply:

 High-current resolution and sensitivity to measure a wide range of load currents
 6½-digit measurement resolution to enable a wide range of measurements on a single current range
 Fast current measurements to test or study load current pulses as narrow as 100 μs
 Linear mode, low noise output

As a battery test instrument:

 Battery capacity test with charging and discharging functions
 Battery charge and discharge process and data logging (voltage, current, resistance, and amp-hour

information)

 Generate a battery model based on battery test results
 Measure open-circuit voltage and resistance

As a battery simulator:

 Simulate a real battery based on a battery model
 Dynamic and static simulation mode to simulate battery output
 Intuitive way to show battery capacity and battery voltage on home screen

Other features:

 Color TFT display with icon-based and soft-key user interface
 Data logging and analysis with graphical display and statistics for trend analysis
 GPIB, USB-TMC, and LAN LXI interfaces for automated test development
 Digital I/O for rich trigger functions
 Direct parameter entry using the front-panel keypad, soft keys, or the navigation control
 Front-panel USB-A connector for flash-drive support
 Front and rear inputs with remote sense connections on the rear-panel connector
 Overcurrent, overvoltage, and overtemperature protection
 Compact, 2U, half rack, stackable form factor fits easily in a test rack

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Section 1: Introduction

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Standard accessories

Accessory

Part number

Model 2281-001 output mating connector

2281-001

Standard LAN crossover cable

N/A

Quick start guide

See the following table for part numbers.

Certification of calibration

Languages

Part number

English

0713430xx*

Simplified Chinese

0713432xx*

Traditional Chinese

0713433xx*

Japanese

0713431xx*

* Where xx represents the revision number.

You will get one of the following quick start guides.

You will also get one of the following power cords:

Option A0 North America and South America. The factory sets the line-voltage selector switch

to 110 V.

Option A1 Universal Euro. The factory sets the line-voltage selector switch to 220 V.
Option A2 United Kingdom. The factory sets the line-voltage selector switch to 220 V.
Option A3 Australia. The factory sets the line-voltage selector switch to 220 V.
Option A4 Chile, Italy. The factory sets the line-voltage selector switch to 220 V.
Option A5 Switzerland. The factory sets the line-voltage selector switch to 220 V.
Option A6 Japan. The factory sets the line-voltage selector switch to 100 V.
Option A7 Denmark. The factory sets the line-voltage selector switch to 220 V.
Option A8 Israel. The factory sets the line-voltage selector switch to 220 V.
Option A9 Argentina. The factory sets the line-voltage selector switch to 220 V.
Option A10 China. The factory sets the line-voltage selector switch to 220 V.
Option A11 India. The factory sets the line-voltage selector switch to 220 V.

Section 1: Introduction Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

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Optional accessories

Optional accessory

Part number

Model 2281-001 output mating connector

2281-001

USB cable type A to B, 1 m (3.3 ft)

USB-B-1

Standard LAN crossover cable

N/A

IEEE-488.2 interface board for the PCI bus

KPCI-488LPA

Double-shielded premium IEEE-488 interface cables, 0.5 m (1.6 ft)

7007-05

Double-shielded premium IEEE-488 interface cables, 1 m (3.2 ft)

7007-1

Double-shielded premium IEEE-488 interface cables, 2 m (6.5 ft)

7007-2

Double-shielded premium IEEE-488 interface cables, 3 m (10 ft)

7007-3

Double-shielded premium IEEE-488 interface cables, 4 m (13 ft)

7007-4

Dual fixed rack-mount kit for 2280S and 2281S instruments

4299-14

Model 2450-TLINK trigger link cable

131909200

Service

Model Number

1 additional year of factory warranty beyond the 3-year factory
warranty (total of 4 years)

2281S-20-6-EW

2 additional years of factory warranty beyond the 3-year factory
warranty (total of 5 years)

2281S-20-6-5Y-EW
KeithleyCare 3-year standard calibration plan

C/2281S-20-6-3Y-STD

KeithleyCare 3-year calibration with data plan

C/2281S-20-6-3Y-DATA

KeithleyCare 5-year standard calibration plan

C/2281S-20-6-5Y-STD

KeithleyCare 5-year calibration with data plan

C/2281S-20-6-5Y-DATA

Available services

For the most up-to-date list of available services and accessories, upgrades, and options for your
instrument, visit tek.com/keithley.

Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual Section 1: Introduction

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General ratings

Category

Specification

Supply voltage range

100 V, 120 V, 220 V, 240 V; each range capable of 10% tolerance, 50 Hz or
60 Hz

Selectable by the line-voltage selector switch on the rear panel

Output connections

See Test connections (on page 2-61).

Environmental conditions

For indoor use only

Altitude: Maximum 2000 meters (6562 feet) above sea level
Operating: 0 °C to 40 °C, full accuracy to 80% relative humidity at up to 35 °C,

noncondensing
Storage: -20 °C to 70 °C, 5% to 95% relative humidity at up to 40 °C and 5% to
60% relative humidity above 40 °C at up to 70 °C

Pollution degree: 2

Model

100 VAC/120 VAC source

220 VAC/240 VAC source

2281S-20-6

250 V, 5 A, time delay

250 V, 2.5 A, time delay

Term

Explanation

ESR

Equivalent series resistance

VOC

Open-circuit voltage

Vt

Terminal voltage

Amp-Hour (A-H)

Unit for battery capacity

SOC

State of charge

Battery model

A profile of a battery that contains the information for Voc and ESR in different
states of charge

V-Full

The voltage of the battery when it is fully charged

V-Empty

The voltage of the battery when it is fully discharged

Dynamic

During the dynamic battery simulation, the open voltage and SOC change with
the charging and discharging

Static

During the static battery simulation, the open voltage and SOC stay the same

The general ratings and connections for the 2281S are listed in the following table.

Line fuse characteristics are shown in the following table.

Terminology in this manual

In this section:

Front-panel overview ................................................................ 2-1

Rear-panel overview ................................................................ 2-3

Front-panel user interface ........................................................ 2-4

Installing the system ............................................................... 2-52

Test connections .................................................................... 2-61

Remote communications interfaces ....................................... 2-68

Set voltage and current limit ................................................... 2-93

Select a measurement function .............................................. 2-96

Select a specific measurement range .................................... 2-97

Protection ............................................................................. 2-100

Saving setups ....................................................................... 2-105

Using the event log .............................................................. 2-107

System information .............................................................. 2-108

Instrument sounds ................................................................ 2-109

Resets .................................................................................. 2-109

POWER switch

Turns the instrument on or off. To turn the instrument on, press
the power switch so that it is in the on position (|). To turn it off,
press the power switch so that it is in the off position (O).

Section 2

General operation

Front-panel overview

The front panel of 2281S is shown below. Descriptions of the controls on the front panel follow the
figure.

Figure 1: 2281S front panel

Section 2: General operation Model 2281S-20-6 DC Power Supply and Battery Simulator Reference Manual

2-2 077114601 / March 2019

MENU key

Opens the main menu. Select the icons using the navigation
control and pressing the ENTER key to open battery, source,
measure, views, trigger, and system screens. For details, see

Power supply menu overview (on page 2-19), Battery test menu
overview (on page 2-32), and Battery simulator menu overview

(on page 2-42).

USB port

Saves reading buffer data to a USB flash drive. You can also
store and retrieve scripts to and from a USB flash drive. The flash
drive must be formatted as a FAT or FAT32 drive.

LCD screen

The 2281S has a high-resolution, 4.3-inch color TFT LCD display.
You can access additional interactive screens by pressing the
front-panel MENU key.

Navigation control

Turning the navigation control: Moves the cursor to the left or

the right to highlight a listed value or menu item so that you can
select it.

ENTER key

Selects the highlighted choice or allows you to edit the selected
field.

EXIT key

Returns to the previous screen or closes a dialog box. For
example, press the EXIT key when the main menu is displayed to
return to the home screen. When you are viewing a subscreen
(for example, the Event Log screen), press the EXIT key to return
to the main menu screen.

TRIGGER key

Accesses trigger-related settings and operations. The action of
the TRIGGER key depends on the instrument state.

Soft keys

There are five soft keys located under the display. They provide
access to additional settings on multiple screens. For example,
press the first soft key when the main menu screen is displayed to
move the cursor to the left.

OUTPUT ON/OFF
switch

Turns the output source on or off. The switch illuminates when the
source output is on.

REMOTE LED
indicator

Illuminates when the instrument is controlled through a remote
interface.

LAN LED indicator

Illuminates when the instrument is connected to a local area network
(LAN).

Front-panel
binding posts

Positive, negative, and ground output binding posts for output
connections.

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Rear-panel overview

LAN port

Supports full connectivity on a 10 Mbps or 100 Mbps network. The
2281S is a version 1.4 LXI Core 2011 compliant instrument that
supports TCP/IP and complies with IEEE Std 802.3 (ethernet
LAN). See LAN communications (on page 2-72).

USB port

USB-B connection for communication, control, and data transfer.
For details, see USB communications (on page 2-88).

Power module

The power module contains the AC line receptacle, the power line
fuse, and the line voltage selector switch. For safety precautions
and other details, see Line fuse replacement (on page A-1) and

Power the instrument on and off (on page 2-58).

Digital I/O port

A digital input/output port that detects and outputs digital signals.
The port provides six digital I/O lines. Each output is set high
(+5 V) or low (0 V) and can read high or low logic levels. Each
digital I/O line is an open-drain signal. Refer to Digital I/O (on
page 3-22) for information.

IEEE-488 port

GPIB connection; the default setting for the 2281S is 5. Refer to

GPIB communication (on page 2-69).

Rear output
terminals

Connections for the source outputs and the sense inputs.

The rear panel of the 2281S is shown below; descriptions follow the figure.

Figure 2: 2281S rear panel

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Front-panel user interface

The front-panel user interface gives you quick access to the functions of this instrument. It includes
the startup screen to choose a function, home screens for each of the functions, and menus for the
functions.

The following topics describe the features of the user interface in more detail.

Startup screen

After you turn on the 2281S, you will see the following startup screen.

Figure 3: Startup screen

The 2281S has three functions you can select from the startup screen:

High-precision power supply: Supplies 20 V, 6 ADC source
Battery test: Conducts battery charging and discharging tests to calculate the capacity and

resistance of the battery and create a battery model

Battery simulator: Simulates a battery to determine what the effect the battery has on the device

under test (DUT) in different states.

You can choose a function by turning the navigation control or pressing the soft keys and pressing

Enter to access the respective home screens of the function.

Home screens

Each function has its own home screen. The following topics describe the home screens.

Status and error indicators

The indicators across the top of the home screen contain information about the following instrument
settings and states. Highlight an indicator by turning the navigation control and then pressing ENTER
to get more information about the present state of the instrument.

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Communication settings status indicator

Indicator

Meaning

Local

Instrument is controlled from the front panel.

GPIB

Instrument is communicating through a GPIB interface.

VXI-11

Instrument is communicating using VXI-11.

USBTMC

Instrument is communicating through a USB interface
(firmware version 1.05 and earlier, port number raw socket 5050; firmware version

1.06 and later, port number raw socket 5025).

WebPage

Instrument is communicating through a web page.

Move the focus to the communication indicator using the navigation control and press the ENTER key
to see a list of present communications settings.

Figure 4: 2281S communication status indicator

Instrument communication activity indicator

The activity indicator is located to the right of the communication settings status indicator. When the
instrument is communicating with a remote interface, the up and down arrows flash.

Figure 5: Instrument communication activity indicator

If a service request has been generated, SRQ is displayed to the right of the up and down arrows. You
can configure the instrument to generate a service request (SRQ) when one or more errors or
conditions occur. This indicator stays on until the serial poll byte is read or all the conditions that
caused SRQ are cleared.

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Level trigger enabled indicator

Green bar

Buffer status

Empty

Less than one-quarter full

Less than half full, more than one-quarter full

Less than three-quarter full, more than half full

More than three-quarter full

When a voltage level trigger or current level trigger is enabled, a solid white square indicator is visible
to the left of the Buffer indicator.

When a level trigger is enabled, data is logged to the buffer when the triggering condition is met.

Buffer indicator

The bar next to Buffer indicates how full the buffer is.

Figure 6: Level trigger enabled indicator

Trigger mode settings indicator

This indicator shows the status of the trigger operation.

Figure 7: Trigger indicator

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List and recall settings indicator

This indicator shows the specified list number or recall settings.

Figure 8: List and recall settings indicator

Error and event indicator

Move the focus to the error and event indicator using navigation control and press the ENTER key to
see the present error and event messages. With the focus on the Event Log button, press ENTER to
see the Error and Event Log.

Figure 9: Error and event indicator

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This indicator has a different appearance based on the type of event that has been logged.

Icon

Description

A serious error has occurred. These major errors are:

 Overprotection error (overvoltage, overcurrent, or overtemperature protection).
 Reverse sense leads.

A normal error has occurred. All the errors except the serious errors listed above are normal errors,
such as SCPI command errors and data overflow errors.

No new error or event messages have been logged since you last viewed the error log.

Indicator

Status description

Output status

The instrument always has one of the following indicators visible:

 OFF: The output is turned off.
 CV: The output is turned on and the power supply is in constant voltage (CV)

mode.

 CC: The output is turned on and the power supply is in constant current (CC)

mode.

 DISABLE: The output is turned off and pressing the OUTPUT switch does

not turn on the output.

Fault status

The fault status indicator means that an error occurred:

 OVP: Overvoltage protection.
 OCP: Overcurrent protection.
 OTP: Overtemperature protection.
 RVS: Reversed sense leads on rear panel.

Calculation status

CALC: If either math or filter operation is enabled, the CALC indicator is displayed
in the OUTPUT view area. If none of them are enabled, the CALC indicator is
cleared.

Relative offset status

REL: If relative offset is enabled, the REL indicator is displayed.

Remote status

RWLOCK: All of the front-panel keys are disabled. The instrument can only be
controlled using a remote interface.

OUTPUT view area

This area displays the values for the present measurements and instrument status indicators.
The following table lists the indicators shown on the right of the OUTPUT view area.

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Home screen for the power supply function

#

Screen element

Description

1

System status and event
indicators

These indicators provide information about the present state
of the instrument. Some of the indicators open up a dialog
box with more information or a settings menu when
selected. For details, see Status and error indicators (on
page 2-4).

2

OUTPUT view area

The green part of the home screen; displays the value of the
present outputs and status indicators.

3

Setting area

Shows the presently set measure range, voltage, and
current limit.

4

Soft-key areas

Shows the present setting values. You can change these
values by pressing the key below the screen.
By pressing the Next button, you can access additional
screens with more soft keys.

The following default screen is displayed when you choose the power supply function. Descriptions of
the numbered screen areas are in the table following the figure.

Figure 10: Power supply home screen

Soft-key areas for the power supply function

The 2281S display has multiple soft-key areas that you can access by pressing the Next soft key.
The soft-key areas give you front-panel access to some instrument settings so that you can change,
enable, or disable them quickly. The following topics describe the soft-key areas for the power supply
function.

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Soft key area 1 for the power supply function

Setting

Description

V-Set

Configure the voltage setting using the numerical keys, soft keys, and
navigation control.

I-Limit

Configure the current setting using the numerical keys, soft keys, and
navigation control.

Range

Press the up arrow to move up a range; press the down arrow to move
down a range. Press Auto to set autorange.

Measure

Configure the measurement function.

V + I

Press soft key 1 to change the measurement function to concurrent.

V

Press soft key 2 to change the measurement function to voltage.

I

Press soft key 3 to change the measurement function to current.

Next

Switch to home screen 2.

Soft-key area 1 for the power supply function contains the settings shown in the following figure and
explained in the table. To change a setting, press the soft key to open a setting window. After
configuration, close the window by pressing the ENTER or EXIT key.

Figure 11: Soft key area 1 for power supply

If you use the navigation control to adjust the voltage and current settings, the values are applied to
the instrument immediately when output is on.

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Soft key area 2 for the power supply function

Setting

Description

Protect

Configure the safety settings using the numerical keys, soft keys, and
navigation control.

OVP

Edit the voltage threshold for overvoltage protection.

OCP

Edit the current threshold for overcurrent protection.

VMAX

Edit the maximum voltage setting value.

Resolution

Specify the measurement resolution for the selected measurement function.

Calculate

Specify the calculate functions including relative, math, and filter.

Rel

Enable or disable the relative function, and set the current value as the
reference value.

Math

Enable or disable the math function.

Filter

Enable or disable the filter function.

Acquire

Configure the source trigger mode.

Immediate

Set the source to immediate triggering.

External

Set the source to external triggering.

Manual

Set the source to manual triggering.

Next

Switch to home screen 3.

Soft key area 2 for the power supply function contains the settings shown in the following figure and
explained in the table.

Figure 12: Soft key area 2 for power supply

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Soft key area 3 for the power supply function

Setting

Description

List

Configure the list function.

Enable

Run a specified list; On or Off.

Number

Specify the list number. The default setting for list number is Demo. You can
run a predefined list. For more information about Demo, see System

Information menu for the power supply function (on page 2-32).

Hold Time

Set the list running time as Point or Time.

End Zero

Enable or disable setting the voltage to 0 V after the list operation has ended.

Mode

Select Sweep or Step list mode and specify the list cycle.

Graph

View the data plot.

Data Sheet

View the data in a spreadsheet format.

Buffer

Clear the data buffer.

Next

Switch to home screen 1.

Soft key area 3 for the power supply function contains the settings shown in the following figure and
explained in the table. To change a setting, press the soft key to open a settings window. After
configuration, close the window by pressing the ENTER or EXIT key.

Figure 13: Soft key area 3

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Home screen for the battery test function

#

Screen element

Description

1

System status and event
indicators

These indicators provide information about the present state of the
instrument. Some of the indicators open a dialog box with more
information or a settings menu when selected.
If the Measure A-H function is on, its status is indicated in this area as
running or pause.
For more details, see Status and error indicators (on page 2-4).

2

OUTPUT view area

The green part of the home screen; displays the value of the present
outputs and status indicators.

 A-H indicates how much power has been transferred between the

battery and the instrument.

 The + or - indicate the direction of the current. The + means the

instrument is sourcing electricity to the battery, and the - means the
battery is outputting electricity to the instrument.

 ON/OFF indicates whether the instrument is outputting electricity.

For other values and settings in this area, please refer to OUTPUT view

area (on page 2-8).

3

Setting area

Shows the presently set voltage and current limit.

4

Soft-key area

Shows the present setting values. You can change these values by
pressing the key below the screen.
By pressing the Next button, you can access additional screens with more
soft keys.

The following default screen is displayed when you choose the battery test function. Descriptions of
the numbered screen areas are in the table following the figure.

For more information about using the battery test function, see Battery test (on page 3-55).

Figure 14: Battery test home screen 1

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Setting

Description

A-H/Watt

Set how the battery capacity is displayed; you can choose between
ampere-hour, instantaneous watts, instantaneous resistance, and
instantaneous capacitance.

V-Set

Set the value of voltage for charging and discharging.

I-Limit

Set the maximum current value for charging; the maximum current for
discharging is always 1 A.

End

Set the threshold current value for stopping charging and discharging.

Next

Switch to home screen 2.

Soft-key areas for the battery test function

The 2281S display has multiple soft-key areas that you can access by pressing the Next soft key.
The soft-key areas give you front-panel access to some instrument settings so that you can change,
enable, or disable them quickly. The following topics describe the soft-key areas for the battery test
function.

Soft key area 1 for the battery test function

Soft-key area 1 contains the settings shown in the following figure and explained in the table. To
change a setting, press the soft key to open a setting window. After configuration, close the window
by pressing the ENTER or EXIT key.

Figure 15: Soft-key area 1 for battery test

If you use the navigation control to adjust the voltage and current settings, the values are applied to
the instrument immediately when output is on.

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Soft key area 2 for the battery test function

Setting

Description

Measure AH

Specify whether to turn on the measuring A-H function or generate a model
after a battery test is complete.

Measure C

Specify whether to measure capacitance.

Script

Specify whether to run a script; you can select a specific index in the script to
run, how many measurement cycles to make, and you can view the results in
a table that can be saved to a USB flash drive.

Sample Int

Set the sampling intervals (in milliseconds) during the charging and
discharging.

Next

Switch to home screen 3.

Setting

Description

OVP

Set the voltage threshold value for overvoltage protection.

Graph

View the graph of the measurement. You can change the view of the graph
using the soft under the graph.

Data Sheet

View measurements in a spreadsheet format.

Buffer

Clear the data buffer.

Next

Switch to home screen 1.

Soft key area 2 contains the settings shown in the following figure and explained in the table. To
change a setting, press the soft key to open a setting window. After configuration, close the window
by pressing the ENTER or EXIT key.

Figure 16: Soft key area 2 for battery test

Soft key area 3 for the battery test function

Soft key area 3 contains the settings shown in the following figure and explained in the table.

Figure 17: Soft key area 3 for battery test

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Home screen for the battery simulator function

#

Screen element

Description

1

System status and
event indicators

These indicators provide information about the present state of the instrument. Some
of the indicators open a dialog box with more information or a settings menu when
selected.
When the Status icon is partially filled with red, it indicates that the battery is being
discharged.
When the Status icon is filled with a lightning bolt symbol, it indicates that the battery
is being charged.

2

OUTPUT view area

This part of the screen displays the status of the battery simulation.
The battery symbol on the left represents the remaining battery capacity.

 SOC means state of charge, the remaining battery capacity shown as a

percentage.

 A-H indicates the battery capacity in ampere-hours.
 ESR indicates the equivalent battery resistance.

The battery symbol in the right represents the output voltage.

 Voc is the open-circuit voltage, represented in dark blue.
 Vt is the battery voltage when it is connected to a load. It changes depending

on the load. It is represented in light blue.

 I displays the charging/discharging current. When the value is in negative (–),

the battery is being charged.

3

Soft-key area

Shows the present setting values. You can change these values by pressing the key
below the screen.
By pressing the Next button, you can access additional screens with more soft keys.

The following default screen is displayed when you choose the battery simulation function.
Descriptions of the numbered screen areas are in the table following the figure.

For details about how to use the battery simulator function, see Battery simulation (on page 3-69).

Figure 18: Battery simulation home screen 1

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Soft-key areas for the battery simulator function

Setting

Description

Model

Choose the model of the battery.

Method

Choose the mode of the simulation; you can choose between Dynamic and Static.

Voc

Set the initial open-circuit voltage for the battery.

SOC

Set the initial battery capacity in percentage.

Next

Switch to home screen 2.

The 2281S display has multiple soft-key areas that you can access by pressing the Next soft key.
The soft-key areas give you front-panel access to some instrument settings so that you can change,
enable, or disable them quickly. The following topics describe the soft-key areas for the battery
simulator function.

Soft key area 1 for the battery simulator function

Soft-key area 1 contains the settings shown in the following figure and explained in the table. To
change a setting, press the soft key to open a setting window. After configuration, close the window
by pressing the ENTER or EXIT key.

Figure 19: Soft key area 1 for battery simulation

If you use the navigation control to adjust the voltage and current settings, the values are applied to
the instrument immediately when the output is on.

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Soft key area 2 for the battery simulator function

Setting

Description

Full V

Set the voltage value when the battery is fully charged. Charging stops when
the voltage reaches this value.

Empty V

Set the voltage value when the battery is completely discharged. Discharging
stops when the voltage reaches this value.

I-Limit

Set the maximum current value for discharging.

Capacity

Set the battery capacity.

Next

Switch to home screen 3.

Setting

Description

OVP

Set the voltage threshold for overvoltage protection.

Graph

View the graph of the measurement.

Data Sheet

View the data sheet of the measurement.

Buffer

Clear the data buffer.

Next

Switch to home screen 1.

Soft key area 2 contains the settings shown in the following figure and explained in the table.

Figure 20: Soft key area 2 for battery simulation

Soft key area 3 for the battery simulator function

Soft key area 3 contains the settings shown in the following figure and explained in the table. To
change a setting, press the soft key to open a setting window. After configuration, close the window
by pressing the ENTER or EXIT key.

Figure 21: Soft key area 3 for battery simulation

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Power supply menu overview

To access the main menu of the power supply, press the MENU key on the 2281S front panel when
you are in the power supply home screen. The organization of the main menu is shown in the figure
below.

Figure 22: Power supply main menu

The main menu is organized into submenus, which are labeled in green across the top of the display.
The icons in each column open interactive screens.

Source menu for the power supply function

The menus organized under Source in the main menu allow you to select, configure, and perform
source and list operations from the 2281S front panel. The following topics describe the settings that
are available on these interactive screens.

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Source Settings menu for the power supply function

Setting

Description

V-Set

Configure the voltage setting using the numerical keys, soft keys, and
navigation control.

I-Limit

Configure the current setting using the numerical keys, soft keys, and
navigation control.

Output

Turn on or off the output. You can also disable the output. Once output is
disabled, the output is off and the OUTPUT key is ignored.

Output Delay

Enable or disable output delay.

Slew Rise

Set the rising rate for voltage source.

Slew Fall

Set the falling rate for voltage source.

Delay Rise

This menu option is only available if Output Delay is set to On. View the
delay time that the instrument waits before turning on the output.

Delay Fall

This menu option is only available if Output Delay is set to On. View the
delay time that the instrument waits before turning off the output.

Setting

Description

Overvoltage Protection

Set the overvoltage protection limit of the source output to restrict the
maximum voltage level that the instrument can source.

Overcurrent Protection

Set the overcurrent protection limit of the source output to restrict the
maximum current level that the instrument can source.

Maximum Voltage

Set the maximum voltage that can be set. This influences the voltage setting
range.

You can change the following settings by pressing the MENU key, moving focus to the Source
Settings icon, and pressing the Enter key.

Source Protection menu for the power supply function

This menu allows you to configure the protection settings.

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Source List menu for the power supply function

Setting

Description

List

Select a list from nonvolatile memory; import a list from an external USB flash
drive; save a list to an external USB flash drive.

Save

Save the present list to nonvolatile memory.

Delete

Delete the specified points from the list.

Insert

Insert one point with default settings before each specified point. The default
settings are: 0.000 V, 0.100 A, 0.100 s.

Copy

Copy the selected settings of the point and insert a new point with the same
settings before each point.

Points

Shows the number of points in the list (read only).

List table

This table shows all the setting values in the list. You can edit them by
moving focus and pressing the ENTER key.

Setting

Description

Source Delay

Configure the delay time using the numerical keys, navigation wheel, and
soft keys.

State

Enable or disable the delay that occurs when the source is turned on.

This menu allows you to set up a source configuration list.

Source Delay menu for the power supply function

This menu allows you to set a delay for the source. For details, refer to Source delay (on page 3-10).

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Measure menu for the power supply function

Setting

Description

Function

Select which type of measurement is active:

 V + I: Concurrent measurement function. The instrument measures

voltage and current at the same time.

 V: Voltage measurement function. The instrument only measures

voltage.

 I: Current measurement function. The instrument only measures

current.

Range

Set the measurement range for the selected measurement function.

Digits

Select the display digits: 6½, 5½, or 4½ digits.

Auto Zero

Set Auto Zero to On so that the instrument periodically gets new
measurements of its internal ground and voltage reference. This setting
increases measurement accuracy, but may slow measurement time.

NPLC

Set the amount of time that the input signal is measured. A lower number of
power line cycles (NPLCs) results in faster reading rates, but increased
noise. A higher number of NPLCs results in lower reading noise, but slower
reading rates.

Power Line Freq

Shows the present power line frequency setting (read only).

The menus organized under Measure in the main menu allow you to select, configure, and perform
measure operations from the 2281S front panel. The following topics describe the settings that are
available on these interactive screens.

Measure Settings menu for the power supply function

This menu contains settings for the presently selected measurement function, which is identified by
the Type indicator in the upper right corner of the menu. The line frequency is also shown here.

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Measure Rel/Filter menu for the power supply function

Setting

Description

Function

Displays the presently selected function.

Rel State

Use the relative offset feature to subtract a set value or a baseline reading
from measurement readings. When you enable relative offset, all subsequent
measurements are displayed as the difference between the actual measured
value and the relative offset value.

Rel Acquire

Acquire the present reading as a relative value.

Reference

Configure the offset value. You can use Rel Acquire to set the present
reading as the relative offset value. You can also specify the relative offset
using the numerical keys, navigation control, and soft keys. The default value
is 0.

Type

The 2281S only supports moving average filtering. This filter continuously
adds measurements to the stack on a first-in, first-out basis, replacing the
oldest measurement in the stack with a new measurement.

Filter State

Enable or disable filtering of measurements.

Count

Sets the number of measurements that are averaged when filtering is
enabled. The number of measurements can be 2 through 100.

Window

Filtering uses a window to control filter threshold. When the input signal
remains within the selected window, measurements continue to be placed in
the stack. If the input signal changes to a value outside the window, the filter
resets and starts processing again, starting with new measurements.

Setting

Description

Type

Shows the type of math function used (read only). When the Math State is set
to On, the mx+b math operation is performed on measurements.

mx+b: Manipulate normal display readings by adjusting the m and b factors.

State

When the state is set to On, any math operations specified for the present
measurement function are performed before completing the measurement.

m(Gain)

Specify scale factor for mx+b math operation. The valid range is –1e6 to
+1e6.

b(Gain)

Specify the offset for mx+b math operation. The valid range is –1e6 to +1e6.

Function

Shows the presently active function (read only).

Units

Specify the units suffix name for mx+b operation. You can only select one
capital letter for the name from the front panel.

Buffer Data Type

Select Reading to store measurements to the buffer without performing math
operations on them.
Select Calc to store measurements to the buffer after performing specified
math operations.

This menu contains settings that specify the way measurement information is returned.

Measure Math menu for the power supply function

This menu contains settings that configure the math function.

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Measure Data Buffers menu for the power supply function

Setting

Description

Size

Set the maximum number of readings the buffer can store (2 to 2500). Note
that when you resize a buffer, the readings contained in that buffer are
cleared.

Mode

Select Always to have the buffer fill continuously, overwriting old data when
the buffer is filled.
Select Next to have the buffer stop collecting data when it is filled (no data is
overwritten).
Select Never to have the buffer stop collecting data.

Statistics

Select statistics to apply to the readings in the buffer. Available statistics:

 Minimum: Minimum value
 Maximum: Maximum value
 Peak-Peak: Maximum value - minimum value
 Mean: Average
 Std Dev: Standard deviation

Statistics Function

Select whether to apply statistics calculations to current or voltage readings.
You can only specify one of them at a time.

Auto Clear

Enable or disable autoclear for the buffer. When autoclear is enabled, the
buffer will automatically clear when the storage process starts.

Statistics Format

Select the data elements to be shown on the graph and data sheet screen.
Available data elements:

 Value: Voltage and current reading
 Time: The timestamp for the data point
 Number: Reading number

Export To USB

Save the buffer to a .csv file, which can be opened by a spreadsheet
program.

Clear Buffer

Clear all the data in the buffer.

From this screen you can save, resize, and clear buffers. You also can set buffer fill mode and
statistics functions.

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Views menu for the power supply function

Setting

Description

Graph

View the readings in a graphical representation.

Statistics

Turn the statistics function On or Off. You can view statistics results on the
graph screen when this function is on.

Window

Fine-tune the output on the graph view screen.

Position

Set the center point of the graph for buffer data. For example, if the buffer
size is 100, a position of 30% means the 30th reading in the buffer is at the
middle point in the plot.

Zoom

Specify the number of readings that are displayed on the screen.

Y-Axis

Select the data that is plotted on the Y-axis. You can select Voltage,
Current, or Both.

I Auto Adjust

Enable or disable the automatic adjustment of the current scale and offset of
the Y-axis. When automatic adjustment is disabled, you can adjust the scale
and offset manually.

V Auto Adjust

Enable or disable the automatic adjustment of the voltage scale and offset of
the Y-axis. When automatic adjustment is disabled, you can adjust the scale
and offset manually.

I Manual Adjust

This menu option is only available when the I Auto Adjust function is set to
Off. Manually adjust the current scale and offset of the Y-axis.

 Scale is the volts/division, or amps/division. A plot has 7 divisions.
 Offset is the value of the lowest division displayed.

V Manual Adjust

This menu option is only available when the V Auto Adjust function is set to
Off. Manually adjust the voltage scale and offset of the Y-axis.

 Scale is the volts/division, or amps/division. A plot has 7 divisions.
 Offset is the value of the lowest division displayed.

Setting

Description

Data Sheet

Show the data in the reading buffer.

Statistics

Turn On or Off the statistics function. You can view statistics results in the
data sheet when this function is on.

The menus organized under View in the main menu allow you to view the data plot, sheet, and
statistics results on the 2281S front panel. The following topics describe the settings that are available
on these interactive screens.

Views Graph menu for the power supply function

Selecting the Graph menu opens a screen that allows you set up and see the measurements in a
graphical format.

Views Sheet menu for the power supply function

This menu allows you to view data in the selected reading buffer.

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Trigger menu for the power supply function

Setting

Description

List type

Shows the list type when the list function is enabled. The 2281S supports
the following types of lists:

 Step: One trigger signal outputs one list step.
 Sweep: One trigger signal outputs the entire list.
 Disable: The list is disabled.

Idle

 Cont:On: Continuous trigger is on.
 Cont:Off: Continuous trigger is off and no readings are taken.

Arm Source

Select the control source for the arm layer.

Arm Count

Set the number of times to repeat the arm event.

Trigger Source

Select the control source for the trigger layer.

Trigger Count

Set the number of times to repeat the trigger event.

Reset Configuration

Reset the trigger settings to factory default, including trigger source and
trigger count.

Sample Count

Set the number of measurements to be performed when a measurement is
requested.

This menus organized under Trigger in the main menu allow you to configure triggering operations
from the 2281S front panel. The following topics describe the settings that are available on these
interactive screens.

Trigger Configure menu for the power supply function

This menu allows you to view and configure the triggering settings. The 2281S has two trigger layers:
Arm layer and trigger layer.

When List is set to On using the front-panel soft keys, this menu is read only.

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Trigger Digital In/Out menu for the Power Supply Function

Setting

Description

Line 1

Specify one of the following line modes for digital I/O line 1:

 Trigger In
 Output HI
 Output LO
 Manual In

Line 2

Specify one of the following line modes for digital I/O line 2:

 Meter Out
 Output HI
 Output LO
 Manual In

Line 3

Specify one of the following line modes for digital I/O line 3:

 Fault Out
 Output HI
 Output LO
 Manual In

Line 4

Specify one of the following line modes for digital I/O line 4 to line 6:

 Output HI
 Output LO
 Manual In

Line 5

Line 6

This menu allows you to configure the mode for each digital I/O line. The 2281S has 6 digital I/O lines
(line 1 to line 6). For details, refer to Digital I/O (on page 3-22).

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Trigger Level menu for the power supply function

Setting

Description

Voltage

 If you set this as On, the triggering point is based on the value of voltage.
 If you set this as Off, the triggering point is not based on the value of voltage.

Current

 If you set this as On, the triggering point is based on the value of current.
 If you set this as Off, the triggering point is not based on the value of current.

Voltage Level

Set the value of the voltage that will trigger the data logging in the data buffer.

Current Level

Set the value of the current that will trigger the data logging in the data buffer.

Voltage
Direction

 If you set this as Rise, the trigger will be activated when the voltage rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the voltage falls below the

triggering point.

Current
Direction

 If you set this as Rise, the trigger will be activated when the current rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the current falls below the

triggering point.

Offset

Set how many points will be saved before the trigger is activated.

This menu allows you to configure a triggering condition to start to log the data in the data buffer
during the test. You can set the triggering point based on the voltage or current. The triggering
condition is based on whether the current or voltage rises or falls.

When the level trigger function is enabled, it clears all the data in the buffer and the buffer mode is
set to Always.

When the level trigger is activated, it clears the data in the buffer (except the points set by the Offset
parameter) and the buffer mode is set to Next.

When the level trigger is enabled, a solid white rectangle is visible at the top of the display screen, as
shown in the following figure.

Figure 23: Level trigger enabled indicator

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You can use the following SCPI commands to configure the level trigger:

Setting

Description

Save

Save the present instrument settings as a user-saved setup. The 2281S
supports up to five setups.

Recall

Return the instrument to the specified setup.

Auto Load Setup1

 If you choose On, the instrument will load setup1 after it is powered

on.

 If you choose Off, the instrument will not load setup1 after it is

powered on.

:TRACe[n]:TRIGger:VOLTage:STATe
:TRACe[n]:TRIGger:VOLTage[:LEVel]
:TRACe[n]:TRIGger:VOLTage:DIRection
:TRACe[n]:TRIGger:CURRent:STATe
:TRACe[n]:TRIGger:CURRent[:LEVel]
:TRACe[n]:TRIGger:CURRent:DIRection
:TRACe[n]:TRIGger:OFFSet

In addition, you can query whether any level trigger has been activated using the following SCPI
command:

:TRACe[n]:TRIGger:OCCUR?

System menu for the power supply function

This menu allows you to configure general instrument operations from the 2281S front panel.

System Save/Recall menu for the Power Supply Function

This menu allows you to save the present settings and any source or measure configuration lists to
internal memory or external USB flash drive. You can also run a setup from internal memory or USB
flash drive.

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System Settings menu for the power supply function

Setting

Description

Interface

Select GPIB, USB, or LAN.

LXI LCI

Reset the LAN configuration

GPIB settings

Description

Address

The default GPIB address is 5. You can set the address to any address from 1 to
30, if it is unique in the system. This address cannot conflict with an address that is

assigned to another instrument or to the GPIB controller.

LAN settings*

Description

TCP/IP Mode

Select Manual to manually set the Local IP, gateway, and subnet mask values.
Select Auto to set the instrument to automatically obtain an IP address.

Gateway

When TCP/IP Mode is set to Manual, you can see the present gateway address.
To change the address, select the button next to Gateway and enter a new
address.

IP Address

When TCP/IP Mode is set to Manual, you can see the present local IP address. To
change the address, select the button next to Local IP and enter a new address.

Subnet

When TCP/IP Mode is set to Manual, you can see the present subnet mask
address. To change the address, select the button next to Subnet and enter a new
address.

MAC Address

Read-only text that shows the present MAC address of the instrument.

Apply Settings

To save any changes you made on the LAN tab, select Apply Settings.

* You must select Apply Settings after changing any of the LAN settings to save your settings.

This menu contains general instrument settings.

Communication settings for the power supply function

This menu allows you to configure GPIB, LAN, and USB communications settings.

To access the System Communication settings screen:

1. Move focus to the communication indicator at the top left of the home screen and press the
ENTER key. A dialog box opens that shows current communication settings.

2. Select Change Settings. The System Communication screen is displayed.

3. Select an interface by moving focus to the Interface button and pressing the ENTER key.

You can also access this menu through the main menu by pressing MENU on the front panel and
selecting Settings (under System) > Communications.

There are no additional settings for the USB interface.

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The 2281S powers up using the last remote interface used.

Setting

Description

Key Click

Turn the instrument key-click sound on or off from this menu.

Backlight Timer

You can set the front-panel display to dim after a period of time, or
you can set it so that it will never dim.

Backlight Brightness

You can adjust the brightness of the front-panel display. Selecting
this setting opens a sliding adjustment scale that adjusts the
brightness as a percent of total brightness.

Time and Date

Set the instrument month, day, year, and time from this menu.

Error Beeper

Turn the error beeper on or off.

System Password

Change the remote connection or calibration passwords. You need
the remote connection password to open the LXI virtual front panel
and send SCPI commands. You need the calibration password
before you can calibrate the 2281S.

Reset
System Reset

Selecting this option resets many of the instrument commands to
their default values. For more information about what commands get
reset, see Reset default values (on page 2-110).

Password Reset

Selecting this option reverts the passwords to their default values.

Settings

Description

Export to USB

Saves the event log to a .csv file on the USB flash drive. The file name is
eventlog.csv.

Clear Event Log

Clears all entries from the event log.

Other system settings for the power supply function

System Event Log menu for the power supply function

The System Event Log menu allows you to view, save, and clear the event log. The event log entries
are error messages, which may indicate that a command was sent incorrectly.

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System Information menu for the power supply function

Demo

When you select Demo mode, you can choose List Mode or Pulse.

Upgrade

Selecting this option initiates a firmware upgrade from a file on a USB flash
drive (the flash drive must be less than or equal to 2 GB and formatted in
the FAT file format).

New

Update the firmware to the latest version. During the upgrade process, the
instrument verifies that the version you are loading is newer than what is on
the instrument. If the version is older or at the same revision level, no
changes are made.

Previous

Selecting this option returns the 2281S to a previous version of the firmware
from a file on a USB flash drive. When you return to a previous version, the
instrument verifies that the version you are loading is earlier than what is on
the instrument.
If there are several versions on the USB flash drive that are older than what
is on the instrument, the newest one is selected.

Calibrate

Start to calibrate the instrument.

The System Information menu shows the serial number, firmware version, and the calibration adjust
date and count. It also allows you to upgrade the firmware and calibrate the instrument.

Battery test menu overview

To access the main menu for the battery test function, press the MENU key on the 2281S front panel
when you are in the battery test home screen. The organization of the main menu is shown in the
figure below.

Figure 24: Battery test main menu

The main menu is organized into submenus, which are labeled in green across the top of the display.
The icons in each column open interactive screens.

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Source menu for the battery test function

Setting

Description

V-Set

Configure the target voltage value for charging and discharging using the
numerical keys, soft keys, and navigation control.

Charge Limit

Configure the maximum current value during charging using the numerical
keys, soft keys, and navigation control.

End Condition

Configure the threshold current value for stopping battery charging and
discharging using the numerical keys, soft keys, and navigation control.

Discharge Limit

Nonconfigurable maximum current value during discharging, normally
around 1 A.

Setting

Description

Overvoltage Protection

Set the overvoltage protection limit of the source output to restrict the
maximum voltage level that the instrument can source.

Overcurrent Protection

Set the overcurrent protection limit of the source output to restrict the
maximum current level that the instrument can source.

Maximum Voltage

Set the maximum voltage that can be set. This setting influences the voltage
range.

Discharge Protection

Set a discharge current at which the 2281S output will turn off to prevent
battery damage.

Setting

Description

Script

Select or import an existing script, or select the script position to save a new
script.

Steps

A read-only field that shows how many steps there are in the script.

Save

Save an existing script or a new script with a name you specify.

Insert

Insert a step in the script before the selected step.

Delete

Delete the selected step or steps.

Copy

Copy the selected step or steps; the steps are copied below the selected
steps.

The menus organized under Source in the main menu allow you to configure the settings for the
battery test from the 2281S front panel. The following topics describe the settings that are available
on these interactive screens.

Source (Dis)charge menu for the battery test function

This menu allows you to configure the stop conditions for the battery test.

Source Protect menu for the battery test function

This menu allows you to configure the protection settings.

Source Script menu for the battery test function

This menu allows you to select, import, save, or edit a script for the battery test.

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Measure menu for the battery test function

Setting

Description

Sample Interval

Configure the measurement time.
The range of value is:

 8.00000e-5 to 0.48 s (if the instrument is supplied by 50 Hz power)
 6.66667e-5 to 0.5 s (if the instrument is supplied by 60 Hz power)

Setting

Description

Voc

The displayed value of the open-circuit voltage of the battery under test.

ESR

The displayed value of the battery resistance.

Delay

Configure the time for the power supply to stay in the high-resistance state
before it resumes the test.

Measure

Get the Voc and ESR value of the battery displayed on this page.

Setting

Description

V-Full

Configure the end voltage for charging.

End Condition

Configure the end current for charging.

V1 (Low Voltage)

Set Ultra-C low voltage.

Source I-Limit

Configure the maximum charging current.

ESR Interval

Configure the ESR sampling frequency.

V2 (High Voltage)

Set Ultra-C high voltage.

The menus organized under Measure in the main menu for battery test allow you to select, configure,
and perform measure operations from the 2281S front panel. The following topics describe the
settings of measure menu that are available on these interactive screens.

Measure V & I menu for the battery test function

This menu contains settings for the V & I measurement. You can only set the sampling interval. The
line frequency is also shown here.

Measure Voc/ESR menu for the battery test function

This menu allows you to configure the Voc and ESR measurement settings to be used during the
battery test. It also allows you to make a single Voc and ESR measurement.

Measure A-H menu for the battery test function

This menu allows you to configure settings for the charging battery test.

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Measure Data Buffers menu for the battery test function

Setting

Description

Size

Displays how many points can be saved in the buffer. For the 2281S, it is
2500 points.

Export to USB

Configures the settings for exporting data saved in the buffer to a USB
flash drive.

Clear Buffer

Clears the data in the buffer.

Setting

Description

Display

Select the view of the graph in terms of time:

 Part: Only the data in the buffer (up to 2500 points) is displayed
 Overall: The data from the whole test period is displayed with the

waveform compressed

Y-Axis

Select the data that is plotted on the Y-axis. You can select Voc, Current,

AH, or ESR.

Waveform

Select the data to be represented in separate waveforms. You can select
Voc, Current, AH, and ESR.

This menu allows you to configure settings for the measurement data buffer.

Views menu for the battery test function

The menus organized under View in the main menu allow you to view the data plot, sheet, and
statistics results on the 2281S front panel. The following topics describe the settings that are available
on these interactive screens.

Views Graph menu for the battery test function

You can access this menu by pressing the MENU key, moving focus to the Graph icon, and pressing
the ENTER key. On the page displayed, you can view the graphic data in the buffer, including Voc,
current, capacity in Amp-Hours, and equivalent series resistance. The values are represented in
different colors.

You can also access this page by selecting Graph in soft key area 3 of the battery test home screen.

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Views Sheet menu for the battery test function

Setting

Description

Model

Choose and open a saved model for battery simulation.

Capacity

Set the capacity of the battery.

Fine/Coarse

Choose the way the battery model is displayed:

 Fine model: The SOC is displayed in 101 rows by every 1%.
 Coarse model: The SOC is displayed in 11 rows by every 10%.

Save

You can edit the battery model and then select Save to store it in internal
memory. You can save up to nine battery models.

You can access this menu by pressing the MENU key, moving focus to the Sheet icon, and pressing
the Enter key. On the page displayed, you can view the raw data in the buffer, including voltage,
current, equivalent resistance, and capacity.

You can also access this page by selecting Data Sheet in soft key area 3 of the battery test home
screen.

Views Model menu for the battery test function

You can access this menu by pressing the MENU key, moving focus to the Model icon, and pressing
the Enter key. On the page displayed, you can view the model of the battery under test.

Trigger menu for the battery test function

This menus organized under Trigger in the main menu allow you to configure triggering operations
from the 2281S front panel.

Trigger Configure menu for the battery test function

The trigger model is not configurable in the battery test and battery simulation modes; all options are
controlled by the instrument. For details about the information visible on this menu screen, see

Trigger Configure menu for the power supply function (on page 2-26).

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Trigger Digital In/Out menu for the battery test function

Setting

Description

Line 1

Specify one of the following line modes for digital I/O line 1:

 Trigger In
 Output HI
 Output LO
 Manual In

Line 2

Specify one of the following line modes for digital I/O line 2:

 Digital Out
 Digital In
 Output HI
 Output LO
 Manual In

Line 3

Specify one of the following line modes for digital I/O line 3:

 Fault Out
 Output HI
 Output LO
 Manual In

Line 4

Specify one of the following line modes for digital I/O line 4 to line 6:

 Digital Out
 Digital In
 Output HI
 Output LO
 Manual In

Line 5

Line 6

This menu allows you to configure the mode for each digital I/O line. The 2281S has six digital I/O
lines (line 1 to line 6). For details, refer to Digital I/O (on page 3-22).

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Trigger Level menu for the battery test function

Setting

Description

Voltage

 If you set this as On, the triggering point is based on the value of voltage.
 If you set this as Off, the triggering point is not based on the value of voltage.

Current

 If you set this as On, the triggering point is based on the value of current.
 If you set this as Off, the triggering point is not based on the value of current.

Voltage Level

Set the value of the voltage that will trigger the data logging in the data buffer.

Current Level

Set the value of the current that will trigger the data logging in the data buffer.

Voltage
Direction

 If you set this as Rise, the trigger will be activated when the voltage rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the voltage falls below the

triggering point.

Current
Direction

 If you set this as Rise, the trigger will be activated when the current rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the current falls below the

triggering point.

Offset

Set how many points will be saved before the trigger is activated.

This menu allows you to configure a triggering condition to start to log the data in the data buffer
during the test. You can set the triggering point based on the voltage or current. The triggering
condition is based on whether the current or voltage rises or falls.

When the level trigger function is enabled, it clears all the data in the buffer and the buffer mode is
set to Always.

When the level trigger is activated, it clears the data in the buffer (except the points set by the Offset
parameter) and the buffer mode is set to Next.

When the level trigger is enabled, a solid white rectangle is visible at the top of the display screen, as
shown in the following figure.

Figure 25: Level trigger enabled indicator

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You can use the following SCPI commands to configure the level trigger:

Setting

Description

High Voltage

Sets the high-voltage (HV) value. When the output voltage reaches this
value, the digital I/O pin, which is set as Digital Out and HV action, outputs
a level signal.

Low Voltage

Sets the low-voltage (LV) value. When the output voltage reaches this
value, the digital I/O pin, which is set as Digital Out and LV action, outputs
a level signal.

Setting

Description

Save

Save the present instrument settings as a user-saved setup. The 2281S
supports up to five setups.

Recall

Return the instrument to the specified setup.

Auto Load Setup1

 If you choose On, the instrument will load setup1 after it is powered

on.

 If you choose Off, the instrument will not load setup1 after it is

powered on.

:TRACe[n]:TRIGger:VOLTage:STATe
:TRACe[n]:TRIGger:VOLTage[:LEVel]
:TRACe[n]:TRIGger:VOLTage:DIRection
:TRACe[n]:TRIGger:CURRent:STATe
:TRACe[n]:TRIGger:CURRent[:LEVel]
:TRACe[n]:TRIGger:CURRent:DIRection
:TRACe[n]:TRIGger:OFFSet

In addition, you can query whether any level trigger has been activated using the following SCPI
command:

:TRACe[n]:TRIGger:OCCUR?

Trigger Limit menu for the battery test function

This menu allows you to configure the voltage limit that triggers the digital I/O pin to output level
signal in the battery test function.

System menu for the battery test function

This menu allows you to configure general instrument operations from the 2281S front panel.

System Save/Recall menu for the battery test function

This menu allows you to save the present settings and any source or measure configuration lists to
internal memory or external USB flash drive. You can also run a setup from internal memory or USB
flash drive.

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System Settings menu for the battery test function

Setting

Description

Interface

Select GPIB, USB, or LAN.

LXI LCI

Reset the LAN configuration

GPIB settings

Description

Address

The default GPIB address is 5. You can set the address to any address from 1 to
30, if it is unique in the system. This address cannot conflict with an address that is

assigned to another instrument or to the GPIB controller.

LAN settings*

Description

TCP/IP Mode

Select Manual to manually set the Local IP, gateway, and subnet mask values.
Select Auto to set the instrument to automatically obtain an IP address.

Gateway

When TCP/IP Mode is set to Manual, you can see the present gateway address.
To change the address, select the button next to Gateway and enter a new
address.

IP Address

When TCP/IP Mode is set to Manual, you can see the present local IP address. To
change the address, select the button next to Local IP and enter a new address.

Subnet

When TCP/IP Mode is set to Manual, you can see the present subnet mask
address. To change the address, select the button next to Subnet and enter a new
address.

MAC Address

Read-only text that shows the present MAC address of the instrument.

Apply Settings

To save any changes you made on the LAN tab, select Apply Settings.

* You must select Apply Settings after changing any of the LAN settings to save your settings.

This menu contains general instrument settings.

System Communication settings for the battery test function

This menu allows you to configure GPIB, LAN, and USB communications settings.

To access the System Communication settings screen:

1. Move focus to the communication indicator at the top left of the home screen and press the
ENTER key. A dialog box opens that shows current communication settings.

2. Select Change Settings. The System Communication screen is displayed.

3. Select an interface by moving focus to the Interface button and pressing the ENTER key.

You can also access this menu through the main menu by pressing MENU on the front panel and
selecting Settings (under System) > Communications.

There are no additional settings for the USB interface.

The 2281S powers up using the last remote interface used.

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Other system submenus for the battery test function

Setting

Description

Key Click

Turn the instrument key-click sound on or off from this menu.

Backlight Timer

You can set the front-panel display to dim after a period of time, or
you can set it so that it will never dim.

Backlight Brightness

You can adjust the brightness of the front-panel display. Selecting
this setting opens a sliding adjustment scale that adjusts the
brightness as a percent of total brightness.

Time and Date

Set the instrument month, day, year, and time from this menu.

Error Beeper

Turn the error beeper on or off.

System Password

Change the remote connection or calibration passwords. You need
the remote connection password to open the LXI virtual front panel
and send SCPI commands. You need the calibration password
before you can calibrate the 2281S.

Reset
System Reset

Selecting this option resets many of the instrument commands to
their default values. For more information about what commands get
reset, see Reset default values (on page 2-110).

Password Reset

Selecting this option reverts the passwords to their default values.

Settings

Description

Export to USB

Saves the event log to a .csv file on the USB flash drive. The file name is
eventlog.csv.

Clear Event Log

Clears all entries from the event log.

System Event Log menu for the battery test function

The System Event Log menu allows you to view, save, and clear the event log. The event log entries
are error messages, which may indicate that a command was sent incorrectly.

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System Information menu for the battery test function

Demo

When you select Demo mode, you can choose List Mode or Pulse.

Upgrade

Selecting this option initiates a firmware upgrade from a file on a USB flash
drive (the flash drive must be less than or equal to 2 GB and formatted in
the FAT file format).

New

Update the firmware to the latest version. During the upgrade process, the
instrument verifies that the version you are loading is newer than what is on
the instrument. If the version is older or at the same revision level, no
changes are made.

Previous

Selecting this option returns the 2281S to a previous version of the firmware
from a file on a USB flash drive. When you return to a previous version, the
instrument verifies that the version you are loading is earlier than what is on
the instrument.
If there are several versions on the USB flash drive that are older than what
is on the instrument, the newest one is selected.

Calibrate

Start to calibrate the instrument.

The System Information menu shows the serial number, firmware version, and the calibration adjust
date and count. It also allows you to upgrade the firmware and calibrate the instrument.

Battery simulator menu overview

To access the main menu for the battery simulator function, press the MENU key on the 2281S front
panel when you are in the battery simulator home screen. The organization of the main menu is
shown in the figure below.

Figure 26: Battery simulator main menu

The main menu is organized into submenus, which are labeled in green across the top of the display.
The icons in each column open interactive screens.

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Battery menu for the battery simulator function

Setting

Description

Model

Choose a battery model from the internal memory to run the battery
simulation. The name of the battery models end with an .mdl extension.
Up to nine models can be saved in the internal memory.

Method

Choose the method of the battery simulation.
If you choose Dynamic, the Voc and SoC of the simulated battery will
change as the simulation charges and discharges, like a real battery.
If you choose Static, the Voc and SoC of the simulated battery will stay the
same.

Voc

Configure the initial battery voltage.

SOC

Configure the initial battery capacity in percentage.

Full V

Configure the end voltage value for charging. The default value is the
maximum Voc value in the battery model

Empty V

Configure the end voltage value for discharging. The default value is
minimum Voc value in the battery model

Resistance Offset

Set the resistance offset, which will increase the resistance value to offset
the resistance caused by connecting wires and other testing equipment.

Setting

Description

Overvoltage Protection

Set the overvoltage protection limit of the source output to restrict the
maximum voltage level that the instrument can source.

Overcurrent Protection

Set the overcurrent protection limit of the source output to restrict the
maximum current level that the instrument can source.

The menus organized under Battery in the main menu allow you to configure the settings for the
battery simulation from the 2281S front panel. The following topics describe the settings that are
available on these interactive screens.

Battery Settings menu for the battery simulator function

You can change the following settings by pressing the MENU key, moving focus to the Settings icon
under Battery menu, and pressing the Enter key.

Battery Protect menu for the battery simulator function

This menu allows you to configure the protection settings.

Measure menu for the battery simulator function

The menus organized under Measure in the main menu allow you to select, configure, and perform
measure operations from the 2281S front panel. The following topics describe the settings that are
available on these interactive screens.

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Measure Settings menu for the battery simulator function

Setting

Description

Sample Interval

Configure the measurement time.
The range of value is:

 8.00000e-5 to 0.48 s (if the instrument is supplied by 50 Hz power)
 6.66667e-5 to 0.5 s (if the instrument is supplied by 60 Hz power)

Setting

Description

Size

Displays how many points can be saved in the buffer. For the 2281S, it is
2500 points.

Export to USB

Configures the settings for exporting data saved in the buffer to a USB
flash drive.

Clear Buffer

Clears the data in the buffer.

Setting

Description

Display

Select the view of the graph in terms of time:

 Part: Only the data in the buffer (up to 2500 points) is displayed
 Overall: The data from the whole test period is displayed with the

waveform compressed

Y-Axis

Select the data that is plotted on the Y-axis. You can select Voc or ESR.

Waveform

Select the data to be represented in separate waveforms. You can select
Voc or ESR.

This menu contains settings for the measurement. You can only set the sampling interval. The line
frequency is also shown here.

Measure Data Buffers menu for the battery simulator function

This menu allows you to configure settings for the measurement data buffer.

Views menu for the battery simulator function

The menus organized under View in the main menu allow you to view the data plot, sheet, and
statistics results on the 2281S front panel. The following topics describe the settings that are available
on these interactive screens.

Views Graph menu for the battery simulator function

You can access this menu by pressing the MENU key, moving focus to the Graph icon, and pressing
the ENTER key. On the page displayed, you can view the graphic data in the buffer, including voltage
and current. The values are represented in different colors.

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You can also access this page by selecting Graph in soft key area 3 of the battery simulator home

Setting

Description

Model

Choose and open a saved model for battery simulation.

Capacity

Set the capacity of the battery.

Fine/Coarse

Choose the way the battery model is displayed:

 Fine model: The SOC is displayed in 101 rows by every 1%.
 Coarse model: The SOC is displayed in 11 rows by every 10%.

Save

You can edit the battery model and then select Save to store it in internal
memory. You can save up to nine battery models.

screen.

Views Data Sheet menu for the battery simulator function

You can access this menu by pressing the MENU key, moving focus to the Sheet icon, and pressing
the Enter key. On the page displayed, you can view the raw data in the buffer, including voltage,
current, equivalent resistance, and capacity.

You can also access this page by selecting Data Sheet in soft key area 3 of the battery simulator
home screen.

Views Model menu for the battery simulator function

You can access this menu by pressing the MENU key, moving focus to the Model icon, and pressing
the Enter key. On the page displayed, you can view the model of the battery under test.

Trigger menu for the battery simulator function

This menus organized under Trigger in the main menu allow you to configure triggering operations
from the 2281S front panel.

Trigger Configure menu for the battery simulator function

The trigger model is not configurable in the battery test and battery simulation modes; all options are controlled by the
instrument. For details about the information visible on this menu screen, see Trigger Configure menu for the power supply

function (on page 2-26).

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Trigger Digital In/Out menu for the battery simulator function

Setting

Description

Line 1

Specify one of the following line modes for digital I/O line 1:

 Trigger In
 Output HI
 Output LO
 Manual In

Line 2

Specify one of the following line modes for digital I/O line 2:

 Digital Out
 Digital In
 Output HI
 Output LO
 Manual In

Line 3

Specify one of the following line modes for digital I/O line 3:

 Fault Out
 Output HI
 Output LO
 Manual In

Line 4

Specify one of the following line modes for digital I/O line 4 to line 6:

 Digital Out
 Digital In
 Output HI
 Output LO
 Manual In

Line 5

Line 6

This menu allows you to configure the mode for each digital I/O line. The 2281S has six digital I/O
lines (line 1 to line 6). For details, refer to Digital I/O (on page 3-22).

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Trigger Level menu for the battery simulator function

Setting

Description

Voltage

 If you set this as On, the triggering point is based on the value of voltage.
 If you set this as Off, the triggering point is not based on the value of voltage.

Current

 If you set this as On, the triggering point is based on the value of current.
 If you set this as Off, the triggering point is not based on the value of current.

Voltage Level

Set the value of the voltage that will trigger the data logging in the data buffer.

Current Level

Set the value of the current that will trigger the data logging in the data buffer.

Voltage
Direction

 If you set this as Rise, the trigger will be activated when the voltage rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the voltage falls below the

triggering point.

Current
Direction

 If you set this as Rise, the trigger will be activated when the current rises above the

triggering point.

 If you set this as Fall, the trigger will be activated when the current falls below the

triggering point.

Offset

Set how many points will be saved before the trigger is activated.

This menu allows you to configure a triggering condition to start to log the data in the data buffer
during the test. You can set the triggering point based on the voltage or current. The triggering
condition is based on whether the current or voltage rises or falls.

When the level trigger function is enabled, it clears all the data in the buffer and the buffer mode is
set to Always.

When the level trigger is activated, it clears the data in the buffer (except the points set by the Offset
parameter) and the buffer mode is set to Next.

When the level trigger is enabled, a solid white rectangle is visible at the top of the display screen, as
shown in the following figure.

Figure 27: Level trigger enabled indicator

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You can use the following SCPI commands to configure the level trigger:

Setting

Description

High Voltage

Sets the high-voltage (HV) value. When the output voltage reaches this
value, the digital I/O pin, which is set as Digital Out and HV action, outputs
a level signal.

Low Voltage

Sets the low-voltage (LV) value. When the output voltage reaches this
value, the digital I/O pin, which is set as Digital Out and LV action, outputs
a level signal.

Setting

Description

Save

Save the present instrument settings as a user-saved setup. The 2281S
supports up to five setups.

Recall

Return the instrument to the specified setup.

Auto Load Setup1

 If you choose On, the instrument will load setup1 after it is powered

on.

 If you choose Off, the instrument will not load setup1 after it is

powered on.

:TRACe[n]:TRIGger:VOLTage:STATe
:TRACe[n]:TRIGger:VOLTage[:LEVel]
:TRACe[n]:TRIGger:VOLTage:DIRection
:TRACe[n]:TRIGger:CURRent:STATe
:TRACe[n]:TRIGger:CURRent[:LEVel]
:TRACe[n]:TRIGger:CURRent:DIRection
:TRACe[n]:TRIGger:OFFSet

In addition, you can query whether any level trigger has been activated using the following SCPI
command:

:TRACe[n]:TRIGger:OCCUR?

Trigger Limit menu for the battery simulator function

This menu allows you to configure the voltage limit that triggers the digital I/O pin to output level
signal in the battery test function.

System menu for the battery simulator function

This menu allows you to configure general instrument operations from the 2281S front panel.

System Save/Recall menu for the battery simulator function

This menu allows you to save the present settings and any source or measure configuration lists to
internal memory or external USB flash drive. You can also run a setup from internal memory or USB
flash drive.

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System Settings menu for the battery simulator function

Setting

Description

Interface

Select GPIB, USB, or LAN.

LXI LCI

Reset the LAN configuration

GPIB settings

Description

Address

The default GPIB address is 5. You can set the address to any address from 1 to
30, if it is unique in the system. This address cannot conflict with an address that is

assigned to another instrument or to the GPIB controller.

LAN settings*

Description

TCP/IP Mode

Select Manual to manually set the Local IP, gateway, and subnet mask values.
Select Auto to set the instrument to automatically obtain an IP address.

Gateway

When TCP/IP Mode is set to Manual, you can see the present gateway address.
To change the address, select the button next to Gateway and enter a new
address.

IP Address

When TCP/IP Mode is set to Manual, you can see the present local IP address. To
change the address, select the button next to Local IP and enter a new address.

Subnet

When TCP/IP Mode is set to Manual, you can see the present subnet mask
address. To change the address, select the button next to Subnet and enter a new
address.

MAC Address

Read-only text that shows the present MAC address of the instrument.

Apply Settings

To save any changes you made on the LAN tab, select Apply Settings.

* You must select Apply Settings after changing any of the LAN settings to save your settings.

This menu contains general instrument settings.

System Communication settings for the battery simulator function

This menu allows you to configure GPIB, LAN, and USB communications settings.

To access the System Communication settings screen:

1. Move focus to the communication indicator at the top left of the home screen and press the
ENTER key. A dialog box opens that shows current communication settings.

2. Select Change Settings. The System Communication screen is displayed.

3. Select an interface by moving focus to the Interface button and pressing the ENTER key.

You can also access this menu through the main menu by pressing MENU on the front panel and
selecting Settings (under System) > Communications.

There are no additional settings for the USB interface.

The 2281S powers up using the last remote interface used.

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Setting

Description

Key Click

Turn the instrument key-click sound on or off from this menu.

Backlight Timer

You can set the front-panel display to dim after a period of time, or
you can set it so that it will never dim.

Backlight Brightness

You can adjust the brightness of the front-panel display. Selecting
this setting opens a sliding adjustment scale that adjusts the
brightness as a percent of total brightness.

Time and Date

Set the instrument month, day, year, and time from this menu.

Error Beeper

Turn the error beeper on or off.

System Password

Change the remote connection or calibration passwords. You need
the remote connection password to open the LXI virtual front panel
and send SCPI commands. You need the calibration password
before you can calibrate the 2281S.

Reset
System Reset

Selecting this option resets many of the instrument commands to
their default values. For more information about what commands get
reset, see Reset default values (on page 2-110).

Password Reset

Selecting this option reverts the passwords to their default values.

Settings

Description

Export to USB

Saves the event log to a .csv file on the USB flash drive. The file name is
eventlog.csv.

Clear Event Log

Clears all entries from the event log.

Other system settings for the battery simulator function

System Event Log menu for the battery simulator function

The System Event Log menu allows you to view, save, and clear the event log. The event log entries
are error messages, which may indicate that a command was sent incorrectly.

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System Information menu for the battery simulator function

Demo

When you select Demo mode, you can choose List Mode or Pulse.

Upgrade

Selecting this option initiates a firmware upgrade from a file on a USB flash
drive (the flash drive must be less than or equal to 2 GB and formatted in
the FAT file format).

New

Update the firmware to the latest version. During the upgrade process, the
instrument verifies that the version you are loading is newer than what is on
the instrument. If the version is older or at the same revision level, no
changes are made.

Previous

Selecting this option returns the 2281S to a previous version of the firmware
from a file on a USB flash drive. When you return to a previous version, the
instrument verifies that the version you are loading is earlier than what is on
the instrument.
If there are several versions on the USB flash drive that are older than what
is on the instrument, the newest one is selected.

Calibrate

Start to calibrate the instrument.

The System Information menu shows the serial number, firmware version, and the calibration adjust
date and count. It also allows you to upgrade the firmware and calibrate the instrument.

Adjusting the backlight brightness and timer

You can adjust the brightness of the 2281S display from the front panel or over a remote interface.
You can also set the backlight to dim after a specified period of time has passed with no front-panel
activity (available for the front-panel display only). The backlight settings are not affected by reset.

Screen life is affected by how long the screen is on at full brightness. The higher the brightness
setting and the longer the screen is bright, the shorter the screen life.

To adjust the backlight brightness from the front panel:

1. Press the MENU key.

2. Under System, select Settings.

3. Highlight the button next to Backlight Brightness and press ENTER. The Backlight Brightness
dialog box opens.

4. Enter a value and press ENTER.

To set the backlight timer from the front panel:

1. Press the MENU key.

2. Under System, select Settings.

3. Select the button next to Backlight Timer and press ENTER. The Backlight Timer dialog box
opens.

4. Select a timer setting and press ENTER.

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To adjust the brightness using the SCPI remote interface:

Send the following command:

:DISPlay:BRIGhtness <brightness>

Where <brightness> is from 1 to 100. For example, 75 represents 75 percent brightness and 100
represents full brightness.

Installing the system

This section contains information on how to install your 2281S power supply.

Bumpers

The 2281S has front and rear bumpers for using the instrument on a benchtop.

Removing bumpers

You can remove the bumpers on the 2281S if you want to mount the instrument in a rack.

If you remove the bumpers, be sure to store them for future benchtop use.

To remove the bumpers:

1. Grasp the front bumper on each side of the 2281S and gently pull it toward you until the bumper
comes off of the instrument.

Figure 28: Removing the front bumper

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Remove all connections to the rear panel of the 2281S before removing the rear bumper.

2. To remove the rear bumper, repeat the procedure in step 1.

Dimensions

The following figures show the mounting screw locations and the dimensions of the instrument with
and without the bumpers.

The instrument weighs 10.67 kg (23.53 lb) with the bumpers and 10.40 kg (22.95 lb) without them.

The following figure shows the mounting screw locations and dimensions. Mounting screws must be
#6-32 with a maximum screw length of 11.13 mm (0.438 in.). The dimensions shown are typical for
both sides of the instrument.

Figure 29: 2281S mounting screw locations and dimensions

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The following figures show the dimensions when the bumpers are installed.

Figure 30: 2281S front and rear panel dimensions with bumpers

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Figure 31: 2281S top and side dimensions with bumpers

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The following figures show the dimensions when the bumpers have been removed.

Figure 32: 2281S front and rear panel dimensions with bumpers removed

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Figure 33: 2281S top and side dimensions with bumpers removed

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Power the instrument on and off

Follow the procedure below to connect the 2281S to line power and turn on the instrument. The
2281S operates on the following ranges: 100 V, 120 V, 220 V, or 240 V at a frequency of 50 Hz or
60 Hz. You need to select the line voltage and frequency on the rear panel. Make sure the line
voltage setting is compatible with the line voltage in your area.

The 2281S must be turned on and allowed to warm up for at least one hour to achieve rated
accuracies.

The power cord supplied with the Model 2281S-20-6 contains a separate protective earth
(safety ground) wire for use with grounded outlets. When proper connections are made, the
instrument chassis is connected to power-line ground through the ground wire in the power
cord. In addition, a redundant protective earth connection is provided through a screw on the
rear panel. This terminal should be connected to a known protective earth. In the event of a
failure, not using a properly grounded protective earth and grounded outlet may result in
personal injury or death due to electric shock.

Do not replace detachable mains supply cords with inadequately rated cords. Failure to use
properly rated cords may result in personal injury or death due to electric shock.

Operating the instrument on an incorrect line voltage may cause damage to the instrument,
possibly voiding the warranty.

Figure 34: 2281S rear panel

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To connect the power cord:

1. Make sure that the front panel POWER switch is in the off (O) position.

2. Properly set the 100 V/120 V or 220 V/240 V selector switch located on the rear panel.

3. Connect the female end of the supplied power cord to the AC receptacle on the rear panel.

4. Connect the other end of the power cord to a grounded AC outlet.

To turn a Model 2281S-20-6 on and off:

On some sensitive or easily damaged devices under test (DUTs), the instrument power-up
sequence can apply transient signals to the DUT that may affect or damage it. When testing
this type of DUT, do not make final connections to it until the instrument has completed its
power-up sequence and is in a known operating state.

1. Disconnect any devices under test (DUTs) from the 2281S before turning the instrument on.

2. To turn your instrument on, press the front-panel POWER switch to place it in the on (I) position.
A status bar is displayed as the instrument powers up. The home screen is displayed when power
up is complete.

3. To turn your instrument off, press the front-panel POWER switch to place it in the off (O) position.

On some sensitive or easily damaged devices under test (DUTs), the instrument power-down
sequence can apply transient signals to the DUT that may affect or damage it. When testing
this type of DUT, disconnect it from the instrument before turning the instrument off.

Turning the 2281S output on

You can turn the 2281S output on from the front panel or by sending remote commands.

To turn the output on using the front panel:

Press the OUTPUT switch. The instrument is in the output-on state when the switch is illuminated.
The instrument is in the output-off state when the switch is not illuminated.

For the power supply function only, you can also turn on the output from the Source Setting screen.
Select the button next to Output and press the State soft key. The output state screen is displayed.
You can enable the output by pressing the On soft key.

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To turn the output on using a SCPI command:

:OUTPut:STATe ON

When you are using a remote interface to control the instrument and the output is turned off,
pressing the OUTPUT switch cannot turn the output on. However, if the output is turned on, you can
press the OUTPUT switch to turn the output off.

Turning the 2281S output off

Turning the 2281S output off does not place the instrument in a safe state.

Hazardous voltages may be present on all output and guard terminals. To prevent electrical
shock that could cause injury or death, never make or break connections to the 2281S while
the instrument is powered on. Turn off the equipment from the front panel or disconnect the
main power cord from the rear of the 2281S before handling cables. Putting the equipment
into an output-off state does not guarantee that the outputs are powered off if a hardware or
software fault occurs.

Using the front panel:

Press the OUTPUT switch. The instrument is in the output-on state when the switch is illuminated.
The instrument is in the output-off state when the switch is not illuminated.

You can also turn off the output from the Source Setting screen. Select the button next to Output
and press the State soft key. The output state screen is displayed. You can turn off the output by
pressing the Off soft key.

Using SCPI commands:

To turn the output off, send the command:

:OUTPut[:STATe] OFF

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Disable the 2281S output

You can disable the 2281S output from the front panel and by sending remote commands. If disabled,
pressing the OUTPUT switch on the front panel does not turn on the output.

Using the front panel:

1. From the home screen, press MENU.

2. Under Source, select Settings.

3. Select the button next to Output and press ENTER. The Output window is displayed.

4. Select Status. The Status window is displayed.

5. Select the box below Disable.

Using a SCPI command:

To disable the output, send the command:

:OUTPut[:STATe] DISable

Test connections

You can use either the front-panel or rear-panel terminals to make connections to the device under
test (DUT). You must use either the front or rear terminals. You cannot use connections to both the
front panel and rear panel for the same test setup; you must choose one or the other.

Hazardous voltages may be present on all output and guard terminals. To prevent electrical
shock that could cause injury or death, never make or break connections to the Model
2281S-20-6 while output is on.

To prevent electric shock, test connections must be configured such that the user cannot
come in contact with conductors or any device under test (DUT) that is in contact with the
conductors. It is good practice to disconnect DUTs from the instrument before powering the
instrument. Safe installation requires proper shields, barriers, and grounding to prevent
contact with conductors.

The basic connection configurations for the 2281S include:

Two-wire sense connection
Four-wire remote sense connection

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Front-panel connector

Front-panel connectors are available to connect load wires for bench operation. A chassis ground
binding post is also provided on the front panel.

There are two locations on the binding post to connect the wire. See the picture above. You can use
one of the methods below to connect the outputs from the front panel:

Insert standard banana plugs into the front connectors as shown in location 1.
Insert safety test leads into the front connectors as shown in location 1. For details, see the

following figure.

Figure 35: Front-panel binding post

Insert the wires into the hole as shown in location 2, and fasten the wires by hand-tightening the

binding posts. The wire size should be from American wire gage (AWG) 20 to AWG 12.

Figure 36: Safety test lead connection

The wire must be heavy enough not to overheat while carrying the short-circuit output
current of the unit. You must meet the wiring requirements described above. Make sure the
wire you use is enclosed inside a safety cover.

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Rear-panel output mating connector

Available connections on the rear output mating connector include the output high (+), output low (-),
sense high (+), and sense low (-) terminals. The rear output terminals accept wire sizes from AWG 20
to AWG 12.

Two-wire local sense connection

You can connect a device to the instrument in a two-wire sense connection as shown in the following
figure.

Figure 37: Two-wire connection

If you use a two-wire sense connection, you can use the offset function of 2281S to cancel out the
wire resistance. For details, refer to Relative offset (on page 4-13).

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Four-wire sense connection

Using four-wire remote sensing connections ensures that the programmed voltage is applied to the
load and compensates for the voltage drop in the leads between the power supply and the load. The
maximum voltage drop is 1 V per lead.

As shipped, the sense terminals are connected to the output terminals by shorting jumpers. Before
connecting the wire, make sure the shorting jumpers have been removed. When you connect the
power supply for remote sensing, the overvoltage protection (OVP) circuit senses the voltage at the
sensing points (load) and not the output terminals.

Figure 38: Four-wire (remote sensing) DUT connection to rear panel

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To reduce the environmental noise, load wires and sense wires must be twisted. For more
information, refer to the following figure.

Figure 39: Four-wire connection with twisted-pair wires

Make sure you make the connections correctly. Incorrect connections between output and
sense terminals will result in a serious error and may damage the device under test (DUT).
For more information, see Open leads detection (on page 2-66) and Reverse sense leads (on
page 2-67).

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Open leads detection

When using four-wire sense connections, a missing or faulty connection with Sense HI, Sense LO,
Output HI, or Output LO results in improperly regulated voltage and inaccurate voltage measurements.
The voltage readback shown on the front panel is not equal to the real output voltage. The open leads
clamp circuit can limit the output voltage between Output HI and Output LO to less than V

V

= V

total

set

+ V

clamp

total

.

Where V
V

clamp

is the voltage setting.

set

is introduced from a clamp circuit, typically less than 7 V. Without the clamp circuit, the

instrument could output its maximum voltage when the open lead occurs.
Example

1. Connect a 300 Ω resistor to the rear-panel mating connector. For details, refer to Four-wire sense

connections (on page 2-64).

2. Set the voltage to 3 V and current limit to 1 A.

3. Turn on the output.
The following figure shows the voltage readback and output voltage when you make a correct

four-wire sense connection.

Figure 40: Correct four-wire connections

4. Power off the instrument and remove one of the test leads.

To avoid damage to the device under test (DUT), you must power off the instrument before
making any changes on the connections. Otherwise, it may damage the device under test
(DUT).

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5. Power on the instrument and repeat steps 1 through 3.
The following figure shows the error that is displayed on the front panel.

Figure 41: Open lead error

You can retrieve the error number and message through a remote interface by sending
the :SYSTem:ERRor? command.

Reversed sense leads

When the following connections occur, the instrument generates a reversed sense leads error.

Sense HI is connected to Output LO
Sense HI is connected to Sense LO
Sense LO is connected to Output HI

When a reverse sense leads error occurs, the instrument:

Generates an overprotection error message.
Displays an error dialog box on the screen.
Turns off the output.
Resets the voltage setting value and current limit to defaults.
Sets the digital I/O line 3 to logic high.

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Figure 42: Reversed sense leads error

To clear the error, you need to clear the Questionable Instrument Summary Event Register bit and
initiate the trigger model using the front panel or SCPI commands. For more information on registers,
refer to Questionable Instrument Summary Event Register (on page D-16).

To clear an overprotection error using the front panel:

When the overprotection error dialog box is displayed, you can press the ENTER key to initiate the
trigger model.

To clear an overprotection error using a SCPI command:

When an overprotection error occurs, send the following command to clear the register and initiate
the trigger model:

:OUTPut:PROTection:CLEar

Remote communications interfaces

You can choose from one of several communication interfaces to send commands to and receive
responses from the 2281S.

The 2281S can be controlled from only one communication interface at a time. The first interface from
which it receives a message takes control of the instrument. To remove control from the present
interface, send the following command:

:SYSTem:COMMunication:ABORt

The 2281S powers up using the last remote interface used.

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Supported remote interfaces

The 2281S supports the following remote interfaces:

GPIB: IEEE-488 instrumentation general purpose interface bus
USB: Type B USB connection

GPIB communications

This topic contains information about GPIB standards, bus connections, and primary address
selection.

The 2281S GPIB interface is IEEE Std 488.1 compliant and supports IEEE Std 488.2 common
commands and status model topology.

You can have up to 15 devices connected to a GPIB interface, including the controller. The maximum
cable length is the lesser of either:

The number of devices multiplied by 2 m (6.5 ft)
20 m (65.6 ft)

You may see erratic bus operation if you ignore these limits.

Install the GPIB driver software

Check the documentation for your GPIB controller for information about where to acquire drivers.
Keithley Instruments also recommends that you check the vendor's website for the latest version of
drivers or software.

Ethernet: Local area network ethernet communications

It is important that you install the drivers before you connect the hardware to prevent associating the
incorrect driver with the hardware.

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Connect GPIB cables to your instrument

To connect an instrument to the GPIB interface, use a cable equipped with standard GPIB connectors,
as shown below.

Figure 43: GPIB connector

To allow many parallel connections to one instrument, stack the connectors. Each connector has two
screws to ensure that connections remain secure. The figure below shows a typical connection
diagram for a test system with multiple instruments.

To avoid possible mechanical damage, stack no more than three connectors on any one
instrument. To minimize interference caused by electromagnetic radiation, use only shielded
GPIB cables. Contact Keithley Instruments for shielded cables.

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Figure 44: IEEE-488 connection to 2281S

.

To connect the instrument to GPIB:

1. Align the cable connector with the connector on the 2281S rear panel. The location of the
connector is shown in the following figure.

2. Attach the connector. Tighten the screws securely but do not overtighten them.

Figure 45: GPIB interface on rear panel

3. Connect any additional connectors from other instruments, as required for your application.

4. Make sure the other end of the cable is properly connected to the controller.

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Set the GPIB address

The default GPIB address is 5. You can set the address to any number from 1 to 30 if it is unique in
the system. This address cannot conflict with an address that is assigned to another instrument or to
the GPIB controller.

GPIB controllers are usually set to 0 or 21. To be safe, do not configure any instrument to have an
address of 21. To change the controller address, see the documentation for the controller.

The address is saved in nonvolatile memory, so it does not change when a reset is done or when the
instrument power is turned off and then turned on again.

To set the GPIB address from the front panel:

1. Press the MENU key.

2. Under System, select Communication. The SYSTEM COMMUNICATION window opens.

3. Select the GPIB interface.

4. Next to Address, select the number. The Set GPIB Address dialog box is displayed.

5. Enter the address.

6. Select OK.

If you are using a 2281S with no front panel, you can set the GPIB address with the SCPI
command :SYSTem:GPIB:ADDRess.

LAN communications

The Model 2281S-20-6 comes with one standard LAN crossover cable for LAN communication.
However, you can use any standard LAN crossover cable (RJ-45, male-to-male) or straight-through
cable to connect your equipment. The instrument automatically senses which cable you have
connected.

The following figure shows the location of the LAN connection on the rear panel of the instrument.
Connect the LAN cable between this connection and the LAN connector on the computer.

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Figure 46: 2281S LAN connection

You can connect the instrument to the LAN in a one-to-one, one-to-many, two-network card, or
enterprise configuration, as described in the following topics.

One-to-one connection

With most instruments, a one-to-one connection is done only when you are connecting a single
instrument to a single network interface card.

A one-to-one connection using a network crossover cable connection is similar to a typical RS-232
hookup using a null modem cable. The crossover cable has its receive (RX) and transmit (TX) lines
crossed to allow the receive line input to be connected to the transmit line output on the network
interfaces.

Figure 47: One-to-one connection with a crossover cable

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One-to-many connection

With a LAN hub, a single network interface card can be connected to as many instruments as the hub
can support. This requires straight-through network (not crossover) cables for hub connections.

The advantage of this method is easy expansion of measurement channels when the test
requirements exceed the capacity of a single instrument. With only the instruments connected to the
hub, this is an isolated instrumentation network. However, with a corporate network attached to the
hub, the instruments become part of the larger network.

Figure 48: One-to-many connection using a network hub or switch

Two network card connection

If you need to connect independent corporate and instrumentation networks, two network interface
cards are required in the computer controller. Though the two networks are independent, stations on
the corporate network can access the instruments, and the instruments can access the corporate
network, using the same computer.

This configuration resembles a GPIB setup in which the computer is connected to a corporate
network, but also has a GPIB card in the computer to communicate with instruments.

Figure 49: Two network card connection

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Instrumentation connection to enterprise routers or servers

This connection uses an existing network infrastructure to connect instruments to the computer
controller. In this case, you must get the network resources from the network administrator.

Usually, the instruments are kept inside the corporate firewall, but the network administrator can
assign resources that allow them to be outside the firewall. This allows instruments to be connected
to the Internet using appropriate security methods. Data collection and distribution can be controlled
from virtually any location.

Figure 50: Instrumentation connection to enterprise routers or servers

Raw socket connection

All Keithley instruments with LAN connections support raw socket communication. This means that
you can connect your computer to the TCP/IP port on the instrument and send and receive
commands. A programmer can easily communicate with the instrument using the Winsock API on
computers with the Microsoft® Windows® operating system or using the Berkeley Sockets API on
Linux® or Apple® computers.

Beginning with firmware version 1.06 and later, the raw socket port number changed to 5025. For
firmware versions 1.06 and earlier, the raw socket port number is 5050.

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Set up LAN communications on the instrument

This section describes how to set up manual or automatic LAN communications on the instrument.

Check communication settings

Before setting up the LAN configuration, you can check the communication settings on the instrument
without making any changes.

To check communication settings on the instrument:

1. Press the MENU key.

2. Under System, select SETTINGS. The SYSTEM SETTINGS window opens.

3. Select COMMUNICATION. The SYSTEM COMMUNICATION window opens.

4. Select one of the three interfaces (GPIB, USB, or LAN) to see the settings for that interface.

5. Press the EXIT key to leave the SYSTEM COMMUNICATION window without making any
changes.

You can also check the settings with the SCPI command:
:SYSTem:COMMunication:LAN:CONFigure

Set up automatic LAN configuration

If you are connecting to a LAN that has a DHCP server or if you have a direct connection between the
instrument and a host computer, you can use automatic IP address selection.

If you select Auto, the instrument attempts to get an IP address from a DHCP server. If this fails, it
reverts to an IP address in the range of 169.254.1.0 through 169.254.254.255.

Both the host computer and the instrument should be set to use automatic LAN configuration.
Though it is possible to have one set to manual configuration, it is more complicated to set up.

To set up automatic IP address selection using the front panel:

1. From the home screen, press MENU.

2. Under System, select SETTINGS. Then select COMMUNICATION.

3. Select the LAN interface.

4. For TCP/IP Mode, select Auto.

5. Select Apply Settings to save your settings.

The 2281S powers up using the last remote interface used.

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If you are using a 2281S with no front panel, you can configure the LAN using SCPI commands. For
details, see the SCPI command :SYSTem:COMMunication:LAN:CONFigure (on page 7-164).

Set up manual LAN configuration

If necessary, you can set the IP address on the instrument manually.
You can also enable or disable the DNS settings and assign a host name to the DNS server.

Contact your corporate information technology (IT) department to secure a valid IP address for the
instrument when placing the instrument on a corporate network.

The instrument IP address has leading zeros, but the computer IP address does not.

To set up manual IP address selection on the instrument:

1. From the home screen, press MENU.

2. Under System, select SETTINGS. Then select COMMUNICATION.

3. Select the LAN interface.

4. For TCP/IP Mode, select Manual.

5. Select the button next to IP Address and enter the LAN IP address using the numerical or soft
keys.

6. Select the button next to Gateway and enter the gateway address.

7. Select the button next to Subnet and enter the subnet mask.

8. Select Apply Settings to save your settings.

If you are using a 2281S with no front panel, you can configure the LAN using SCPI commands. For
details, see the SCPI command :SYSTem:COMMunication:LAN:CONFigure (on page 7-164).