Tektronix 2268 DC Power Supply User Manual

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Series 2268

850-Watt Programmable DC Power Supplies

Reference Manual

2268S-901-01 Rev. A / January 2015

*P2268S90101A*

2268S-901-01

A Greater Measure of Condence

A Tektr onix Company

850 Watt DC Power Supplies

Series 2268

Reference Manual

Cleveland, Ohio, U.S.A.

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

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

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

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

Document number: 2268S-901-01 Rev. A / January 2015

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 qualified 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 Instruments 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.

2268S-901-01 Rev. A / January 2015 i

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, as defined in the specifications and operating information, and as shown on the instrument or test fixture panels, or switching card.

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.

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

If a

The user documentation in all cases where the symbol is marked on the instrument.

The contact with these voltages.

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

The

If this properly disposed of according to federal, state, and local laws.

The WARNING heading in the user documentation explains dangers 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.

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 Instruments. Standard fuses with applicable national safety approvals may be used if the rating and type are the same. 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 Instruments to maintain accuracy and functionality of the product). If you are unsure about the applicability of a replacement component, call a Keithley Instruments office for information.

symbol on an instrument means caution, risk of danger. The user must refer to the operating instructions located in the

symbol on an instrument means caution, risk of electric shock. Use standard safety precautions to avoid personal

symbol indicates a connection terminal to the equipment frame.

symbol is on a product, it indicates that mercury is present in the display lamp. Please note that the lamp must be

To clean an instrument, use a damp cloth 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 January 2013.

ii 2268S-901-01 Rev. A / January 2015

Table of Contents

INTRODUCTION ...................................................................................................................... 11

ELCOME ........................................................................................................................... 11

XTENDED WARRANTY ........................................................................................................ 11

E C

ONTACT INFORMATION ....................................................................................................... 11

EATURES AND OPTIONS ..................................................................................................... 12

F U

NPACKING AND INSPECTING ............................................................................................... 12

Inspect for Damage ...................................................................................................................... 12

Shipment Contents ....................................................................................................................... 12

ERIES 2268 850-WATT MODELS ........................................................................................ 13

ACK MOUNT KIT OPTIONS .................................................................................................. 13

R F

RONT PANEL FAMILIARIZATION ........................................................................................... 13

EAR PANEL FAMILIARIZATION ............................................................................................. 15

INSTALLATION ....................................................................................................................... 17

ASIC SETUP PROCEDURE ................................................................................................... 17

TEP 1: INSPECTING AND CLEANING ..................................................................................... 18

Initial Inspection............................................................................................................................ 18

Periodic Cleaning ......................................................................................................................... 18

TEP 2: LOCATION AND MOUNTING ....................................................................................... 19

Rack Mounting ............................................................................................................................. 19

Ventilation ..................................................................................................................................... 19

TEP 3: CONNECTING AC INPUT POWER .............................................................................. 20

AC Input Connector ...................................................................................................................... 20

TEP 4: SELECTING LOAD WIRES ......................................................................................... 21

Load Wiring .................................................................................................................................. 21

Insulation Rating........................................................................................................................... 21

Current Carrying Capacity ............................................................................................................ 21

Maximum Load Wiring Length For Operation With Sense Lines ................................................. 22

Noise and Impedance Effects ...................................................................................................... 22

TEP 5: PERFORMING FUNCTIONAL TESTS ............................................................................ 23

Powering the Power Supply On/Off ............................................................................................. 23

Voltage and Current Mode Operation Checks ............................................................................. 24

TEP 6: CONNECTING LOADS ............................................................................................... 25

DC Output Connectors ................................................................................................................. 25

20 V-40 V Models ......................................................................................................................... 25

60 V-150 V Models ....................................................................................................................... 25

Inductive Loads and Batteries ...................................................................................................... 26

Connecting Single Loads ............................................................................................................. 27

Connecting Multiple Loads ........................................................................................................... 27

TEP 7: CONNECTING REMOTE SENSING .............................................................................. 28

2268S-901-01 Rev. A / January 2015 iii

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LOCAL OPERATION ............................................................................................................... 30

NTRODUCTION .................................................................................................................... 30

I C

ONFIGURING SETTINGS FROM THE FRONT PANEL ................................................................ 30

Using the Rotary Adjust/Enter Control ......................................................................................... 30

Coarse and Fine Adjustment Modes ............................................................................................ 31

AVIGATING THE MENU SYSTEM ........................................................................................... 32

Setting VOLTS and AMPS Modes ............................................................................................... 32

Normal Display Mode and Inactivity Timeout ............................................................................... 33

ISPLAY MESSAGES ON THE FRONT PANEL ........................................................................... 35

TANDARD (LOCAL) OPERATION ........................................................................................... 37

PERATING MODES ............................................................................................................. 37

Constant Voltage (CV) Mode Operation ...................................................................................... 37

Constant Current (CC) Mode Operation ...................................................................................... 38

Constant Power (CP) Mode Operation ........................................................................................ 38

Automatic Mode Crossover .......................................................................................................... 38

HIPPED CONFIGURATION (LOCAL OPERATION) .................................................................... 41

NABLING THE OUTPUT ........................................................................................................ 41

E E

NABLING THE AUXILIARY OUTPUT ....................................................................................... 42

UTPUT AUTO START MODE (AUTO RESTART) ...................................................................... 42

UXILIARY AUTO START MODE ............................................................................................. 43

A C

ONSTANT POWER MODE .................................................................................................... 43

LARMS AND ERRORS.......................................................................................................... 44

A C

LEARING ALARMS .............................................................................................................. 45

Clearing Triggered and Manual Alarms ....................................................................................... 45

Clearing a Flash Failure Alarm ..................................................................................................... 45

Clearing Automatic Alarms ........................................................................................................... 46

Front Panel Alarm LED ................................................................................................................ 46

Alarm Masking .............................................................................................................................. 47

Alarm Output Latching ................................................................................................................. 48

ETTING FOLDBACK MODE ................................................................................................... 49

ESETTING ACTIVATED FOLDBACK PROTECTION ................................................................... 50

R U

SING OVER VOLTAGE PROTECTION (OVP) .......................................................................... 50

Defining the OVP Set Point .......................................................................................................... 50

SING UNDER VOLTAGE PROTECTION (UVP) ........................................................................ 51

Defining the UVP Set Point .......................................................................................................... 51

VER CURRENT PROTECTION (OCP) ................................................................................... 51

SING OVER TEMPERATURE PROTECTION LOCK (OTP) ......................................................... 52

Defining the OTP Mode ................................................................................................................ 52

Resetting in Latch Mode .............................................................................................................. 52

SING THE EXTERNAL SHUTDOWN FUNCTION ....................................................................... 53

Activating the External Shutdown Function ................................................................................. 53

Controlling the External Shutdown Function ................................................................................ 53

Defining the Polarity of the External Shutdown Signal................................................................. 54

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850 Watt DC Power Supplies Reference Manual Table

LOOP PROTECTION .............................................................................................................. 54

Setting up Loop Protection ........................................................................................................... 54

NTERLOCK FUNCTION.......................................................................................................... 56

Defining the Interlock Mode ......................................................................................................... 56

UTPUT PROTECTION .......................................................................................................... 56

Programming Voltage Output Preset ........................................................................................... 56

Programming Current Output Preset ........................................................................................... 57

OWER ON STATUS SIGNAL ................................................................................................. 57

ARDWARE MALFUNCTION ALARMS ...................................................................................... 58

URRENT CONFIGURATION MEMORY SETTINGS .................................................................... 58

SER SETTING MEMORY LOCATIONS .................................................................................... 59

Saving User Setting Memory Locations ....................................................................................... 59

Recalling User Setting Memory Locations ................................................................................... 60

OCAL LOCKOUT ................................................................................................................. 61

Enabling Local Lockout ................................................................................................................ 61

Disabling Local Lockout ............................................................................................................... 61

ESETTING THE POWER SUPPLY .......................................................................................... 62

SING MULTIPLE POWER SUPPLIES ...................................................................................... 63

ONFIGURING MULTIPLE SUPPLIES FOR SERIES OPERATION .................................................. 64

Load Considerations .................................................................................................................... 64

Connecting to the Load in Local Sensing Mode .......................................................................... 65

Connecting to the Load in Remote Sensing Mode ...................................................................... 66

ONFIGURING MULTIPLE SUPPLIES FOR CURRENT SHARING OPERATION (APG METHOD) ....... 67

Setting up the Controller Unit ....................................................................................................... 67

Setting up the Slave Units ............................................................................................................ 68

Setting Over Voltage Protection (OVP) ........................................................................................ 68

Setting Foldback Protection ......................................................................................................... 69

ONNECTING TO THE LOAD IN LOCAL SENSING MODE (PARALLEL CONTROL METHOD) ............ 69

ONNECTING TO THE LOAD IN REMOTE SENSING MODE (PARALLEL CONTROL METHOD) ......... 70

C P

OWER SAVING CONTROL (SLEEP MODE) ............................................................................. 70

ANALOG PROGRAMMING & ISOLATED ANALOG PROGRAMMING .................................. 72

NTRODUCTION .................................................................................................................... 72

I A

NALOG PROGRAMMING (APG) OF OUTPUT VOLTAGE AND OUTPUT CURRENT ....................... 72

EMOTE PROGRAMMING OPTIONS........................................................................................ 73

Analog Monitor Signals ................................................................................................................ 73

Auxiliary Outputs .......................................................................................................................... 73

Analog Programming (APG) Connector J1 .................................................................................. 74

Making Control Connections ........................................................................................................ 75

Wiring ........................................................................................................................................... 76

NALOG PROGRAMMING MODE ............................................................................................ 76

Analog Programming With External Voltage Source ................................................................... 76

Voltage-Controlled Voltage APG Setup ....................................................................................... 77

2268S-901-01 Rev. A / January 2015 v

Table of Contents Series 2268 850 Watt DC Power Supplies Reference Manual

Voltage-Controlled Current APG Setup ....................................................................................... 79

NALOG PROGRAMMING WITH EXTERNAL RESISTOR.............................................................. 81

Resistive-Controlled Voltage APG Setup ..................................................................................... 82

Resistive-Controlled Current APG Setup ..................................................................................... 84

OLTAGE AND CURRENT READBACK ..................................................................................... 86

SOLATED ANALOG PROGRAMMING MODE (ISOL) .................................................................. 87

AUX Output and Isolated Analog Programming (ISOL) Connector ............................................. 87

Making ISOL Control Connections ............................................................................................... 89

ISOL Programming With External Voltage Source ...................................................................... 89

Voltage-Controlled Voltage ISOL Setup ...................................................................................... 90

Voltage-Controlled Current ISOL Setup ....................................................................................... 92

NALOG PROGRAMMING WITH EXTERNAL RESISTOR.............................................................. 94

Resistive-Controlled Voltage ISOL Setup .................................................................................... 95

Resistive-Controlled Current ISOL Setup .................................................................................... 97

OLTAGE AND CURRENT READBACK (ISOLATED) ................................................................... 99

UERY REMOTE CONTROL SOURCE STATE .......................................................................... 99

REMOTE OPERATION .......................................................................................................... 101

NTRODUCTION .................................................................................................................. 101

ARDWARE AND CONNECTION SETUP ................................................................................. 101

H C

ONFIGURING REMOTE CONTROL USING RS-232 ............................................................... 102

RS-232 Communication Cable with RJ-45 to DB-9 ................................................................... 103

RS-232 Communication Cable with RJ-45 to DB-25 ................................................................. 104

ONFIGURING REMOTE CONTROL USING RS-485 ............................................................... 106

RS-485 Communication Cable with RJ-45 to DB-9 ................................................................... 106

RS-485 Communication Cable with Two RJ-45s ....................................................................... 107

ONFIGURING REMOTE CONTROL USING USB .................................................................... 108

Setting Up the PC to Use the USB Connection ......................................................................... 108

ONFIGURING REMOTE CONROL USING GPIB .................................................................... 114

GPIB Pin Description ................................................................................................................. 114

Communication with Your Device .............................................................................................. 115

Selecting a Communication Port ................................................................................................ 115

ONFIGURING REMOTE CONTROL USING ETHERNET/LAN (ENET) ....................................... 117

ULTIPLE POWER SUPPLY CONNECTIONS TO RS-485 BUS .................................................. 118

Multiple Power Supply Setup ..................................................................................................... 118

ERMINAL CONFIGURATION ................................................................................................ 119

Data Format ............................................................................................................................... 119

End of Message ......................................................................................................................... 119

HyperTerminal ............................................................................................................................ 119

ELECTING THE APPROPRIATE COMMUNICATION PORT ........................................................ 122

Data Rate Setting (Kbps) ........................................................................................................... 122

Multichannel Address Setting ..................................................................................................... 123

Remote Interface Addressing ..................................................................................................... 123

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850 Watt DC Power Supplies Reference Manual Table

Multichannel Commands Explained ........................................................................................... 124

TATUS REPORTING IN SCPI ............................................................................................. 125

TATUS REGISTERS MODEL FROM IEEE 488.2 ................................................................... 127

Status Byte ................................................................................................................................. 128

Error/Event Queue (ERR) .......................................................................................................... 128

Questionable Status Register Summary (QSR) ......................................................................... 128

Message Available (MAV) .......................................................................................................... 129

Standard Event Status Summary (ESB) .................................................................................... 129

Master Summary Status (MSS) ................................................................................................. 129

Request Service (RQS) .............................................................................................................. 129

Operation Status Register Summary (OSR) .............................................................................. 130

Standard Event Status Register (SESR) ................................................................................... 131

TANDARD SCPI REGISTER STRUCTURE ............................................................................ 134

OPER

ATION STATUS REGISTER ......................................................................................... 135

Current Share Sub-Register ....................................................................................................... 137

Operation Status Register Commands ...................................................................................... 138

Current Sharing Sub-Register Commands ................................................................................ 139

Shutdown Sub-Register Commands .......................................................................................... 140

Protection Sub-Register Commands.......................................................................................... 141

QUES

TIONABLE STATUS REGISTER ................................................................................... 142

VOLTage Sub-Register .............................................................................................................. 144

TEMPerature Sub-Register ........................................................................................................ 144

Questionable Status Register Commands ................................................................................. 145

Voltage Status Register Commands .......................................................................................... 146

Temperature Status Register Commands ................................................................................. 147

SCPI

ERROR/EVENT QUEUE .............................................................................................. 148

ESET COMMAND .............................................................................................................. 150

LEAR ALL STATUS REGISTERS ......................................................................................... 151

Clear Status Command .............................................................................................................. 151

SCPI Preset Status .................................................................................................................... 151

OMMAND LINE HELP SYSTEM ........................................................................................... 152

Querying Help for all Command Headers .................................................................................. 152

Querying Help for Legacy Command Headers .......................................................................... 153

OCKING AND UNLOCKING THE FRONT PANEL ..................................................................... 154

UTO SEQUENCE PROGRAMMING ....................................................................................... 154

A C

ONFIGURE OTHER PROTECTION MECHANISMS .................................................................. 160

Foldback Protection ................................................................................................................... 160

Over Temperature Protection ..................................................................................................... 161

Loop Protection Enable/Disable ................................................................................................. 161

Interlock Enable/Disable ............................................................................................................ 161

AVE AND RECALL ............................................................................................................. 162

ET ANALOG PROGRAMMING LEVEL ................................................................................... 162

ET REMOTE PROGRAMMING INTERFACE ............................................................................ 162

2268S-901-01 Rev. A / January 2015 vii

Table of Contents Series 2268 850 Watt DC Power Supplies Reference Manual

PROTECTION MASK (ENABLE ALARMS) ............................................................................... 163

LAN/ETHERNET SETUP AND COMMUNICATION ............................................................... 164

NTRODUCTION .................................................................................................................. 164

I S

ETTING UP LAN/ETHERNET .............................................................................................. 164

ASICS ............................................................................................................................. 164

Communication Cable Requirements ........................................................................................ 164

ENET Connector ........................................................................................................................ 165

ENET Connector LEDs .............................................................................................................. 166

OCAL AREA NETWORK (LAN) ........................................................................................... 166

Media Access Control (MAC) Address....................................................................................... 166

Communication Configuration .................................................................................................... 166

LAN Connection ......................................................................................................................... 167

Direct-to-PC Connection ............................................................................................................ 167

Private Network Connection ....................................................................................................... 167

ONNECTING TO A NETWORK ............................................................................................. 169

Connecting with PC on Same Side of Router as Power Supply ................................................ 169

Connecting with Power Supply Hidden Behind a Router ........................................................... 170

Socket Port Number ................................................................................................................... 172

Instrument Drivers and Application Software ............................................................................. 173

LXI

DISCOVERY BROWSER SOFTWARE ............................................................................... 173

ETTING LAN PARAMETERS ............................................................................................... 173

Setting LAN Parameters via Serial or USB Port ........................................................................ 173

Setting LAN Parameters via Web Interface ............................................................................... 173

ETTING A STATIC IP ADDRESS THROUGH ETHERNET, USB, AND SERIAL INTERFACES .......... 176

Ethernet ...................................................................................................................................... 176

USB ............................................................................................................................................ 177

RS232 (SERIAL) ........................................................................................................................ 184

SYSTEM

COMMANDS .................................................................................................... 190

Subsystem Syntax...................................................................................................................... 190

CALIBRATION AND TROUBLESHOOTING ......................................................................... 193

NTRODUCTION .................................................................................................................. 193

I M

AIN VOLTAGE AND CURRENT CALIBRATION PRINCIPLE ...................................................... 194

Understanding the Problem ....................................................................................................... 194

Step 1: Gain Calibration ............................................................................................................. 195

Step 2: Offset Calibration ........................................................................................................... 195

Step 3: Recalibrate Gain ............................................................................................................ 196

TORING CALIBRATION DATA ............................................................................................. 196

ALIBRATING THE OUTPUT VOLTAGE .................................................................................. 197

Gain Calibration.......................................................................................................................... 197

Offset Calibration........................................................................................................................ 197

ALIBRATING THE OUTPUT CURRENT.................................................................................. 198

Gain Calibration.......................................................................................................................... 198

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Offset Calibration........................................................................................................................ 198

VER VOLTAGE PROTECTION CALIBRATION ........................................................................ 199

ON-ISOLATED ANALOG PROGRAMMING CALIBRATION ......................................................... 200

Non-isolated Voltage Monitoring Calibration .............................................................................. 200

Non-isolated Current Monitoring Calibration .............................................................................. 201

Non-isolated Voltage Programming of Voltage Calibration ....................................................... 202

Non-isolated Resistive Programming of Voltage Calibration ..................................................... 203

Non-isolated Voltage Programming of Current Calibration ........................................................ 204

Non-isolated Resistive Programming of Current Calibration ..................................................... 205

ALIBRATION PROCEDURE FOR ISOLATED MODES ............................................................... 206

Isolated Voltage Monitoring Calibration ..................................................................................... 206

Isolated Current Monitoring Calibration ..................................................................................... 207

Isolated Voltage Programming of Voltage Calibration ............................................................... 208

Isolated Resistive Programming of Voltage Calibration ............................................................. 209

Isolated Voltage Programming of Current Calibration ............................................................... 210

Isolated Resistive Programming of Current Calibration ............................................................. 211

APG

CALIBRATION ............................................................................................................ 212

Calibrating the Input Voltage APG Signal .................................................................................. 212

Calibrating the Input Current APG Signal .................................................................................. 213

ESTORE FACTORY CALIBRATION ...................................................................................... 214

ESTORE DEFAULT CALIBRATION ....................................................................................... 214

SER DIAGNOSTICS ........................................................................................................... 214

U E

MERGENCY SHUTDOWN ................................................................................................... 215

NUSUAL OR ERRATIC OPERATION ..................................................................................... 215

U T

ROUBLESHOOTING FOR OPERATORS ................................................................................. 215

SCPI COMMAND REFERENCE ............................................................................................ 216

CONFORMANCE INFORMATION ................................................................................... 216

SCPI

Codes and Standards ................................................................................................................ 216

IEEE 488.2/SCPI Syntax and Style............................................................................................ 217

SCPI Command Hierarchy ......................................................................................................... 217

Using SCPI Commands ............................................................................................................. 218

Parameter Types ........................................................................................................................ 221

SCPI

COMMAND TREE ....................................................................................................... 222

COMMAND SUMMARY ................................................................................................ 228

SCPI

IEEE 488.2 Commands .............................................................................................................. 228

Readback Commands ................................................................................................................ 230

SCPI Commands for Output Control .......................................................................................... 231

SCPI Commands for Calibration ................................................................................................ 232

SCPI Commands to Clear All Protection Mechanisms .............................................................. 234

SCPI Commands for Foldback Protection ................................................................................. 234

SCPI Commands for Power ....................................................................................................... 234

SCPI Commands for Triggering ................................................................................................. 235

System Commands .................................................................................................................... 235

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Table of Contents Series 2268 850 Watt DC Power Supplies Reference Manual

Status Commands ...................................................................................................................... 237

Protection Commands ................................................................................................................ 242

Auto Sequence Commands ....................................................................................................... 242

ERROR MESSAGES.............................................................................................................. 243

RROR MESSAGES ............................................................................................................ 243

Command Error List ................................................................................................................... 244

Execution Error List .................................................................................................................... 245

Device-Specific Error List ........................................................................................................... 246

Query Error List .......................................................................................................................... 246

SPECIFICATIONS .................................................................................................................. 247

PECIFICATIONS ................................................................................................................ 247

Output Performance Specifications............................................................................................ 247

Environmental Specifications (Indoor use) ................................................................................ 248

Mechanical Specifications .......................................................................................................... 248

Regulatory Approvals ................................................................................................................. 248

ECHANICAL DIMENSIONS ................................................................................................. 249

x 2268S-901-01 Rev. A / January 2015

Supply.

In this section:

WELCOME

Section 1

Introduction

This section describes the features of the 2268 Series 850 Watt Power

Thank you for choosing a Keithley Instruments product. The Series 2268 850-Watt DC power supply is designed for use in the laboratory and for test applications. It also has excellent regulation and low output voltage ripple. The digital displays provide accurate readings of voltage and current and also provide for easy, precise setting of output values using digital entry of current and voltage values. Output voltage can be set from the front panel, using a remote analog voltage or resistance, or over any of the digital interfa ces: LAN, USB, GPIB, or RS-485. Voltage and current analog outputs are also available for remote monitoring and analog control.

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 th e price o f a repa ir. Exte nded w arranties are av ailable o n new and existing products. Contact your local Keithley Instruments representative for details.

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, or call Ke ithley Instruments corporate headquarters (toll-free inside the U.S. and Canada only) at 1-800-935-5595, or from outside the U.S. at +1-440-248-0400. For worldwide contact numbers, visit the Keithley Instruments website (http://www.keithley.com).

2268S-901-01 Rev. A / January 2015 11

Introduction Series 2268 850 Watt DC Power Supplies Reference Manual

FEATURES AND OPTIONS

The Series 2268 Programmable DC Power Supply provides stable, variable output voltage and current for a broad range of development and system requirements. The power supplies have a high power density, numerous indus try standard interfaces, and a num ber of excellent features:

• RS-232, RS-485, GPIB, Ethernet (ENET), analog programming (APG), and USB

built-in ports

• Seamless switching between front panel and any digital interface (RS-232, RS-485,

USB, GPIB or ENET)

• Simultaneous digital displays for both voltage and current

• Front panel control by rotary Adjust/Enter knob, permitting high resolution output

setting

• Active Power Factor Correction (PFC) reduces input current and input current harmonics

• Automatic crossover system allowing the power supply to switch between Constant

Current, Constant Voltage and Constant Power operating modes

• Parallel or series connection among multiple units to produce greater diversity or to use

in higher power applications

• Short-circuit protection of DC outputs, providing greater operating safety

• Built-in APG and ISOL interface to provide a galvanically isolated analog voltage

control of the output, master/slave output tracking, and remote Enable/Disable for safety and precision

• Remote output voltage sensing to automatically compensate for cable losses.

• Software calibrated

• Three user setting memory locations

UNPACKING AND INSPECTING

Inspect for Damage

Upon receiving the Model 2268, careful ly unpack the unit, and inspec t for any obvious signs of physical damage that might have occurred during shipment. Notify the shipping agent of any damage immediately.

Shipment Contents

The following items are included with every Series 2268 order:

• Series 2268 power supply

• Series 2268 product information CD-ROM

• AC line power cord

• Series 2268 additional accessories, as ordered

12 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Introduction

Model

Output Voltage

Output Current

2268-20-42

0-20 V

0-42 A

2268-40-21

0-40 V

0-21 A

2268-60-14

0-60 V

0-14 A

2268-80-10.5

0-80 V

0-10.5 A

2268-100-8.5

0-100 V

0-8.5 A

2268-150-5.6

0-150 V

0-5.6 A

Important: We recommend that you provide additional rear support to the Series 2268 when mounting it in a rack.

Number of Units

Model Number

Item

Description

Front panel power switch

Front panel display see Figure 2

Air intake vents

SERIES 2268 850-WATT MODELS

RACK MOUNT KIT OPTIONS

Rack-mount kits are available for the Series 2268 instruments. The table below shows the available models. Complete details and installa tion instructions are in cluded in the docum ent that ships with each rack-mount kit.

Single 2268-RMK-1

Dual 2268-RMK-2

FRONT PANEL FAMILIARIZATION

Figure 1: Series 2268 850-Watt Front Panel

2268S-901-01 Rev. A / January 2015 13

Introduction Series 2268 850 Watt DC Power Supplies Reference Manual

Item

Description

Rotary Adjust/Enter control

Constant Voltage (CV) Mode LED (green)

Constant Current (CC) Mode LED (green)

Output Current Display

Model Identification Label

Output Voltage Display

Alarm Indicator LED (red)

OUTPUT ENABLE Main button

OUTPUT ENABLE Aux button

9-Position Mode Control (For detailed information, see

Figure 2: Series 2268 850-Watt Front Panel Display and Controls

“Configuring Settings from the Front Panel” on page 30).

14 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Introduction

REAR PANEL FAMILIARIZATION

Figure 3: Series 2268 850-Watt, 20 V to 40 V Rear Panel

Figure 4: Series 2268 850-Watt, 60 V to 150 V Rear Panel

2268S-901-01 Rev. A / January 2015 15

Introduction Series 2268 850 Watt DC Power Supplies Reference Manual

Item

Description

20 V– 40 V Models: DC Output Terminal Positive (6.5 mm hole diameter) 60 V–150 V Models: DC Output Connectors Positive

20 V– 40 V Models: DC Output Terminal Negative (6.5 mm hole diameter) 60 V–150 V Models: DC Output Connectors Negative

3 (J2)

Ethernet (ENET) or GPIB Connector

4 (J4)

RS-232/RS-485 Connector In Port

AC Input Connector (IEC Type)

Chassis Ground Stud

7 (J1)

Analog Programming (APG) Connector. For pin information, see page 74.

8 (J3)

AUX Output and Isolated Analog Programming (ISOL) Connector. For pin information, see page 87.

9 (J5)

USB Connector

10 (J6)

RS-485 Connector Multichannel Port

Ethernet/LAN Connector

Fan Exhaust Vents

16 2268S-901-01 Rev. A / January 2015

Inspect

Inspect the power supply.

“Step 1: Inspecting and

Install

Install the power supply

“Step 2: Location and Mounting”

Connect Input

Connect AC input power.

“Step 3: Connecting AC

Select Wires

Select wires that are

“Step 4: Selecting Load Wires”

Test

Perform functional tests for

“Step 5: Performing

Connect Loads

Connect the load wires to

“Step 6: Connecting Loads”

Connect

Connect remote sensing

“Step 7: Connecting

In this section:

This section provides information and procedures for inspecting, installing, and testing the power supply.

BASIC SETUP PROCEDURE

Below is a summary of the basic setup procedure with references to the relevant sections in this section. Refer to this table if you are unfamiliar with the installat ion requirements for the power supply. Complete each step in the sequence give

Section 2

Installation

Step Description Action Reference

Cleaning” on page 18.

(benchtop or rack mount). Ensure adequate ventilation.

Power

correctly rated for the maximum DC output current.

voltage mode operation, current mode operation, and front panel controls.

the DC output.

Remote Sensing (if required)

connectors on power supply to load.

on page 19.

Input Power” on page 20.

on page 21.

Functional Tests” on page

23.

on page 25.

Remote Sensing” on page

28.

2268S-901-01 Rev. A / January 2015 17

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

STEP 1: INSPECTING AND CLEANING

Initial Inspection

When you first receive your unit, perform a physical check:

1. Inspect the unit for any scratches and cracks, broken switches, connectors or displays.

2. Ensure that the packing box contains a power cord.

3. If you see external damage or suspect internal damage, contact the carrier immediately.

Periodic Cleaning

The power supply only requires periodic cleaning, not routine servicing. Whenever a unit is removed from operation, clean the metal surfaces with naphtha or an equivalent solvent, and clean the front panel with a weak solution of soap and water. Use low-pressure compressed air to blow dust from components on the printed circuit boards.

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Series 2268 850 Watt DC Power Supplies Reference Manual Installation

STEP 2: LOCATION AND MOUNTING

The power supply may be rack-mounted or used in benchtop applications.

Rack Mounting

Keithley offers a Single and a Dual Rack Kit (2268-RMK-1 and 2268-RMK-2). See "Rack Mount Kit Options" on page 13 for information about available rack mount kits. To purchase a rack mount kit, contact your local Keithley Instruments off ice, sales partner, or distributor, or call Keithley Instruments corporate headquarters (toll-free inside the U.S. and Canada only) at 1-800-935-5595, or from outside the U.S. at +1-440-248-0400. For worldwide contact numbers, visit the Keithley Instruments website (http://www.keithley.com).

Ventilation

Whether operating the pow er supply in a ra ck or on a bench, allow ai r to re ach the ventilatio n inlets on the front and rear of the unit for cooling. The direction of airflow is from the front of the unit to the back of the unit. Ventilat ion space is not required at the top, bottom or sides of the power supply.

2268S-901-01 Rev. A / January 2015 19

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

The AC input cord is the disconn ect device f or the power su pply . The plug must

STEP 3: CONNECTING AC INPUT POWER

WARNING: Shock hazard

Disconnect AC power from the unit before re moving the cover. E ven with the front panel power switch in the Off position, live line voltages are exposed when the cover is removed. Repairs must be made by an Authorized Service Center.

WARNING: Shock hazard

There is a potential shock hazard if the power supply chassis and cover are not connected to an electrical ground via the safety ground in the AC input connector. Ensure that the power supply is connected to a grounded AC outlet with the recommended AC input cord configured for the available line voltage as described in this section.

WARNING: Shock hazard

be a non-locking plug which is readily identifiable by and accessible to the operator. The input cord must be no longer than 9.84 feet (3 m).

AC Input Connector

The AC input connector is a standard IEC 16 A 250 V male connector located on the rear panel of the power supply. The AC input cord provided is rated for 30 A, 300 V.

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Series 2268 850 Watt DC Power Supplies Reference Manual Installation

Wire Size (AWG)

Maximum Current (Amps)

Wire Size (AWG)

Maximum Current (Amps)

2.5 6 61

18 4 4

16 6 2

155

10 1 192

1/0

247

2/0

303 8 36

n/a

STEP 4: SELECTING LOAD WIRES

This section provides recommendations for selecting minimum load wire sizes.

Load Wiring

To select the wiring for connecting the load to the power supply, consider the following factors:

• Insulation rating of the wire. Current carrying capacity of the wire.

• Maximum load wiring length for operation with remote sense lines.

• Electrical noise and impedance effects of the load lines.

Insulation Rating

Use load wiring with a minim um insulation rating equiv alent to the m aximum output voltage of the power supply.

Current Carrying Capaci ty

The load wiring must have a current carrying capacity greater than the output rating of the power supply to ensure that the load wiring will not be damaged if the load is shorted. The table that follo ws shows the maxim um current ra ting for v arious gaug es of wir e rated for 10 5 °C operation, based on a maximum current density of 450 A/cm

Operating at the maximum current rating shown in the table below resu lts in an approximately 30 °C temperature rise for an appropriately-sized load wire operating in free air. Where load wiring must operate in areas with elevated ambient temperatures or bundles with other wiring, use larger gauges or wiring rated for higher temperatures.

Current Carrying Capacity for Load Wi ring

2268S-901-01 Rev. A / January 2015 21

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

WIRE GAUGE (AW G)

LOAD CURRENT (AMPS)

Maximum Load Wiring Length For Operation With Sense Lines

Figure 5: Maximum Load Wire Length for 1 V Line Drop

WIRE LENGTH (FEET)

Noise and Impedance Effects

To minimize noise pickup or radiation, use shielded twisted pair wiring of the shortest possible length for load sense wires. Connect the shield to the power supply chassis. Where shielding is impossible or impractical, simply twisting the wires together will offer some noise immunity.

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Series 2268 850 Watt DC Power Supplies Reference Manual Installation

STEP 5: PERFORMING FUNCTIONAL TESTS

The functional test procedures include:

• Power-on and front panel functional checks

• Voltage mode operation and current mode operation checks.

For information on local operation, see the section on “Local Operation” on page 30 for adjusting front panel controls and settings.

Powering the Power Supply On/Off

To power on the power supply:

1. Ensure that the front panel power switch is in the Off position.

2. Ensure that the AC line voltage is within operating range.

3. Connect the line cord to a grounded AC outlet.

4. Turn the front panel power switch to the On position. After a short power-on delay, illuminates on the output voltage and curren t

displays, followed by

After approximately 1 second, the display returns to normal status.

To power off the power supply:

 Turn the front panel power switch to the Off position.

will blink on the display. The ALARM LED illuminates. After a short delay,

all lights on the display will not be illuminated.

2268S-901-01 Rev. A / January 2015 23

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

Voltage and Current Mode Oper a ti on Check s

To perform the voltage and current mode operation checks:

1. Ensure that the front panel power switch is in the On position and the output is disconnected.

2. If the OUTPUT ENABLE Main button is illuminated, press the button to turn off the output.

3. To check voltage mode operation, turn the 9-position mode control to the VOLTS position.

The voltage set point will blink dimming and then return to full brightness. For more information, see the section on “Local Operation” starting on page 30.

4. Adjust the voltage to 5 V.

5. To check current mode operation, turn the 9-position mode control to AMPS position.

Verify that the current set point is blinking in the output current display.

6. Adjust the current to 1 A.

7. Press the OUTPUT ENABLE Main button to turn On.

8. Turn the front panel power switch to the Off position.

9. Turn the front panel power switch to the On position.

10. Connect a short circuit across the output terminals. Use leads of sufficient current carrying capacity. (See “Step 4: Selecting Load Wires” on page 21.)

11. Press the OUTPUT ENABLE Main bu tton to enable th e output. The button will be illuminated when the output is enabled.

CC Mode LED illuminates and the voltage and current are displayed. CC Mode LED illuminates and the preset load current is displayed.

12. Turn the front panel power switch to the Off position.

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Series 2268 850 Watt DC Power Supplies Reference Manual Installation

operating at an output

hazardous voltages, ensure that the load and its connections have no accessible

inals, ensure terminals of opposite

STEP 6: CONNECTING LOADS

This section describes how to connect loads to the power supply for both single and m ultiple loads.

WARNING: Shock hazard

There is a shock hazard at the power supply output when greater than 40 V. To protect personnel against accidental contact with

live parts.

CAUTION: Cable damage

When making connections to the output term polarity do not touch. Load cables and sense wires should be provided with strain relief.

DC Output Connectors

WARNING: Shock hazard

Disconnect the AC input before making any connections. A shock hazard may be present at the output terminals. Allow 15 second s after the AC power has been removed before making any connections.

20 V-40 V Models

The 20 V-40 V models are equipped with output terminals, as shown in Figure 3.

60 V-150 V Models

The 60 V-150 V models are equipped with output connectors, as shown in Figure 4. These models have output currents that may require users to use wire diameters that would not fit into a single output connector, so there are two output connectors in pa rallel to increase the potential current carrying capacity of load wiring.

2268S-901-01 Rev. A / January 2015 25

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

The power supply requires freewheeling and blocking diodes across the

supply from damage caused by power being fed back into the supply and

Selecting

The diode must have a voltage rating at least 20% greater than the power

power supply's output rating. C onnect the cathode to th e positive output and th e

or a varistor ac ross the output t o

protect the power supply. The breakdown voltage rating for the TVS or varistor

Inductive Loads and Batterie s

CAUTION

output while driving inductive loads or batteries to protect the power

from high voltage transients.

Diodes

supply's output voltage and have a current rating greater than or equal to the

anode to the return. Where positive load transients such as back EMF from a motor may occur,

connect a Transient Voltage Suppressor (TVS)

must be approximately 10% higher than the rated supply output.

Figure 6: Diode Placement

26 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Installation

Terminal

Power Supply

Terminal

Load

– Local Sense

+ Output

+ Local Sense

– Output

Connecting Single Loads

Figure 7 shows the recommended load connections for a single load which is sensing its voltage locally. Loca l sens e li nes show n ar e the d efaul t connec tions at the r ear pan el A PG J1 connector. The load lines should use the largest gauge and shortest leng th of w ire p ossible to ensure optimal performance.

You do not need remote sensing for basic operation of your power supply. However, if you wish to correct any small drops in your load lines, then use the remote sensing feature. See “Step 7: Connecting Remote Sensing” on page 28for more inform ation.

Figure 7: Connecting Single Loads

Connecting Multiple Loads

The proper connection of distributed loads is an important aspect of power supply use. The common method of connection is a radial load connection. Power is connected to each load individually from a single pair of terminals designated as the positive and negative distribution terminals. This pair of terminals may be the power supply output terminals, the load terminals, or a dis tinct set of term inals especia lly estab lished f or di stribu tion u se. I n this scheme, there are no ground loops and the effect of one load upon another is minimized.

2268S-901-01 Rev. A / January 2015 27

Installation Series 2268 850 Watt DC Power Supplies Reference Manual

Output +

Load

Pin J1.1 on APG connector

Output terminals on power supply

Output –

Chassis ground stud +SNS

-SNS

Pin J1.6 on APG connector

STEP 7: CONNECTING REMOTE SENSING

WARNING: Shock hazard

There is a potential shock hazard at the sense connectors when using a power supply at an output greater than 40 V. Select wiring with a minimum insulation rating equivalent to the maximum output voltage of the power supply for use as local sense jumpers or for remote sense wires. Ensure that connections at the load end are shielded to prevent contact with hazardous voltages.

Remote sen sing pe rm its y ou to sh if t th e r egu latio n po int of the power supply from the outpu t terminals to the load or other distribution terminals.

Use shielded twisted pair wiring of 20 to 26 AWG for best noise performance. Make sure that the shielded twisted pair wiring insulation is rated higher than the maximum output voltage of the power supply. If possible, one end of the shield of the sense lines shoul d be attached to the chassis ground of the power supply.

Figure 8: Remote Sense Connection

To connect the remote sense wires:

1. Ensure that the front panel power switch is in the Off position.

2. Using a small flat blad e screw driver, rem ove the two sense jumpers from pins J1.1 and J1.2, and from pins J1.5 and J1.6 on the APG Connector.

28 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Installation

e load without

connected to the negative load terminal. Do not reverse these connect ions or the

Important: Long load leads with large capacitance at the load and remote

Measures to reduce inductance and/or capacitance (raising resonant frequency) or using local sense can be beneficial in stabilizing the system.

3. Connect one end of the shield of the twisted pair wire to the chassis ground point on the power supply.

4. Connect the positive sense line (+SNS) from the positiv e regulation po int as close as possible to the load termin a ls to pin J1-1.

5. Connect the negative sense line (-SNS) from the return of the load to pin J1-6. To compensate for losses in power leads connected to the output, the power supply

provides sense connections beside the output terminals. With remote sense leads in place, the power supply regulates to the displayed voltage at the point where the sense lines are connected to the output leads. With the sense lines disconnected, the power supply regulates the voltage at the output terminals.

CAUTION: Equipment damage

Do not operate the power supply with sense lines connected to th also connecting the load po wer lea ds to the output terminals.

CAUTION: Reverse polarity

Avoid reversing positive (+) and negative (-) sense connections. When using remote sense to compensate for load line losses, ensure that the positive sense line is connected to the positive load terminal and the negative sense line is

power supply may be damaged.

sensing can cause voltage instability due to inductance of the load leads.

2268S-901-01 Rev. A / January 2015 29

In this section:

This section provides the procedures for local (front panel) operation such as:

• Configuring settings.

• Operating in constant voltage mode, constant current mode, and constant power

mode).

• Using the protection features.

• Using multiple power supplies

INTRODUCTION

Once you have installed the power supply and connected both the AC input power and the load (covered in “Installation” on page 17), the power supply is ready for local operation. To turn the power supply on, see “Powering the Power Supply On/Off” on page 23

Section 3

Local Operatio n

CONFIGURING SETTINGS FROM THE FRONT PANEL

The 9-position mode control is used with the rotary Adjust/Enter control to configure settings in local operation. See Figure 2 for location of the front panel features.

Using the 9-position mode control, select one of nine modes: VOLTS, AMPS, FLD, PRT, SAV, RCL, CAP, and VAP. See Figure 9 below and the table that follows for detailed information on the nine modes.

Figure 9: 9-Position Mode Control

Using the Rotary Adjust/Enter Control

The rotary Adjust/Enter control is used to change settings and set the value selected. The front panel displays information on the output voltage and output current displays. Each display has a maximum of four characters that are made up of 7 segments.

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Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Coarse adjustment mode

When using local operation to set the current and voltage set

Fine adjustment mode

Pressing the rotary Adjust/Enter control to change the mode to fine adjustment mode, provides the abi lity to manipulate the la st significant digit. Once the exact de sired value fo r the setting ha s

9 Positions on the Mode

Turning the rotary Adjust/Enter

Pressing the rotary Adjust/

VOLTS (Voltage

Select the voltage set point in coarse

Set the value selected and cycle

AMPS (Current Programming)

Select the current set point in coarse

Set the value selected and cycle

FLD (Foldback)

Select Foldback option: CC, CV or

Set the value selected and cycle

PRT (Protection)

Select the OVP set point (see page

Set the value selected and cycle

SAV (Save User Preset)

Select the user setting memory

Save user setting memory

RCL (Recall User Preset)

Select the user setting memory

Recalling User Setting

Load user setting memory

CAP (Current Analog

Select the programming source and

Set the value selected and cycle

VAP (Voltage Analog

Select the programming source and

Set the value selected and cycle

PGM (Programming Options)

Select the remote interface to be used

Select interface/Option and

Coarse and Fine Adjustment Modes

The coarse and fine ad jus tment modes are used for s et ting th e voltage and current set po int s, OVP and UVP settings.

points, use the coarse adjustment mode (default) followed by the fine adjustment mode (described next). The coarse adjustment mode quickly adjusts the settings in large increments to reach the desired value.

been selected, press the rotary Adjust/Enter control to commit the value to the unit.

Control Knob

Programming)

control lets you...

or fine adjustment modes. See “Automatic Mode Crossover” on page 38.

or fine adjustment modes. See “Constant Curr e nt (CC) Mode Operation” on page 38.

none. See “Setting Foldback Mode” on page 49.

50). Select the UVP set point (see page 51.) Select OTP temperature and Shutdown (see page 52.)

location. See “Saving Us er Setting Memory Locations” on page 59.

location. See “ Memory Locations” on page 60.

Enter control lets you...

to the next setting.

values.

values into the power supply.

Programming)

2268S-901-01 Rev. A / January 2015 31

select the range.

for control, local lockout or current sharing.

to the next setting.

cycle to the next setting.

Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

NAVIGATING THE MENU SYSTEM

The menu system follows a select and set model with the exception of the VOLTS and AMPS modes. See “Setting VOLTS and AMPS Modes” next.

The general procedure for setting up the features in the select and set model is:

1. To select a mode, rotate the 9-position Mode control to the desired mode or press the rotary Adjust/Enter control once to activate the current selection on the mode control knob. See Figure 9.

2. To select the feature or setting, rotate the rotary Adjust/Enter control to scroll through the different available settings of that mode.

The settings appear on the output current display.

3. Press the rotary Adjust/Enter control to select the feature or setting.

4. Set each value using the rotary Adjust/Enter control. When the value has been selected, press the rotary Adjust/Enter control to commit the updated value. Additional values may become available, depending on the setting that is being configured.

Setting VOLTS and AMPS Modes

The only exceptions to the select and set model are the VOLTS and AMPS modes which do not allow the selection of tracking and select and set mode by turning the rotary Adjust/Enter control. In VOLTS and AMPS modes, the default entry mode setting is automatically selected as either voltage or current tracking, respectively.

Voltage and current values can be set in tracking mo de or select and set mode u sing the rotary Adjust/Enter control:

• Tracking mode—the new values take effe ct as the rotary Adjust/Enter contro l is rotated.

• Select and set mode—the new values do not take effect until the rotary Adjust/Enter

control is pressed. See “Normal Display Mode and Inactivity Timeout” on page 33.

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Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Important: Each user memory setting location stor e s the timeout so that

beginning users and expert users are not required to use the same timeout

To access the tracking mode for entering voltage and current:

1. Select the VOLTS or AMPS position on the 9-position mode control. If the set point is blinking, the unit is in coarse tracking mode.

• When the VOLTS mode is selected, the voltage set point will blink in the output

voltage display.

• When the AMPS mode is selected, the current set point will blink in the output

current display.

2. Use the rotary Adjust/Enter control to adjust the set point. Not e th at there is an activity tim e out (see “Normal Display Mode and Inactivity T imeout” on page 33).

The adjustments you make to the set point affect the opposing output value (voltage when in AMPS mode or current when in VOLTS mode), which will update in the non-blinking display.

3. Press the rotary Adjust/Enter control to enter fine adjust tracking mode. The set point blinks faster when the unit is in fine adjust tracking mode.

4. Use the rotary Adjust/Enter control to fine tune the set point.

5. Once the set point has been selected, press the rotary Adjust/Enter control to exit tracking mode and return to normal display mode.

To access the select and set entry mode for the voltage and current set points:

1. Select VOLTS or AMPS position on the 9-position mode control.

2. Press the rotary Adjust/Enter control three times in succession to enter coarse Pre-Set Adjustment.

3. Press the rotary Adjust/Enter control one more time to enter fine Pre-Set Adjustment.

4. Press the rotary Adjust/Enter control once again to set the value. The units can also timeout (adjustable) to exit the menu. O nce Pre-Set Mode is entered,

CrPU or FnPU will appear in the voltage display.

Normal Display Mode and Inac ti vi ty Timeout

Normal display mode appears on the output voltage and current displays when the configuration changes from the front panel have been completed or when the inactivity timeout occurs (default is 3 seconds). Normal display mode shows the output voltage and current values.

If a timeout occurs before the changes made to the value have been set, the changes will not be saved and you will have to re-enter the chang es. The inactiv ity tim eout i s v ariable from 1 to 20 seconds and can only be changed using the SCPI command.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel>]:FPANel[:TIMeout]

2268S-901-01 Rev. A / January 2015 33

Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Figure 10: Front Panel Menu System

34 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Display Text

Text Description

Negative Polarity

RS 232

RS 485

RS 485L

All segments On, Power Up

Positive Polarity

Alternating Current

RS 485 Address

Analog Programming

Power On Autostart

Auxiliary Autostart

Current Anal og Programming

Clear

Constant Curr e nt

Controller

Constant Power

Constant Voltage

Coarse Current Pre-set Mode

Coarse Voltage Pre-set Mode

Current Share (same as CUrrShAr)

Current

Current Share (same as CShr)

Fold Delay

Done

Error (debug)

Foldback

Fail

Fan Flash

Fine Current Preset Mode

Fine Voltage Preset Mode

Foldback

Data rate (kbps)

GPIB Interface

DISPLAY MESSAGES ON THE FRONT PANEL

The front panel displays on the power supply will use text as shown in the table that fol lows to indicate the status or mode.

2268S-901-01 Rev. A / January 2015 35

Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Display Text

Text Description

Interlock

ENET Interface

Current APG Level

Voltage APG Level

Lock

Local

Loop Protection

Off On

Output Protection

Over Current Protection

Over Temperature Protection

Over Voltage Protection

Over Voltage Protection fine adjustment

OVP Calibration

Polarity

Protection mode

Power Supply Unit

Isolated Resistive Analog Programming

Recall Preset

Remote Programming/Interface

Non-Isolated Resistive Analog Programming

Controller (current share contr oller)

Share (current share)

Multichannel Remote Interface

Soft reset

Save Preset

Shutdown

Slave (current share slave)

Sleep Mode

Isolated Analog Voltage Pro gramming

Non-Isolated Ana lo g Vol ta ge P ro gr ammi ng

USB Interface

Under Voltage protection coarse adjustment

Under Voltage protection fine adjustment

Voltage Analog Programming

Voltage

A blinking numeric value is either a voltage or current set point in tracking mode. The display in which the set point appears, either output voltage or output current displays, indicating the type of set point: voltage or current.

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Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Output enabled

When the output is turned on, both the voltag e and current rise as quick ly

the CC mode LED or the CV mode LED, one of whi ch will illuminate on the front panel.

Output disabled

The mode of operation is not determined until the output is enabled. The

disabled.

STANDARD (LOCAL) OPERATION

The power supply can be controlled by two m ethods, either from the front panel o r from any of the remote interfaces. Fr ont pane l control is referred to as local opera tion (de fau lt se tting ) while contr ol v ia a ny of the rem ote inte rf aces is calle d r emote operation. To se t up the powe r supply for remote operation, see the section on “Remote Operation” starting on page 101. Once the remote connection has been established , the pow er supply can switch se amlessly between local operation and any digital interface (RS-232, RS-485, GPIB, USB and Ethernet).

Local lockout (page 61) is a feature that allows the fron t panel to be locked so that accidental button presses are ignored. This feature is often u sed to lock ou t the front panel whi le a user is controlling the power supply from a remote location.

The output of the power supply has three modes of operation: Constant Voltage, Constant Current, and Constant Power. All three of the operating modes are available regardless of which control method (local or remote) is used.

OPERATING MODES

The output mode in which the power supply operates at any given time depends on the following factors:

• Output voltage set point V

• Output current set point I

• Impedance of the attached load R

SET

The three output modes of operation are Constant Voltage (CV) mode (see page 37), Constant Current (CC) mode (see page 38), and Constant Power (CP) mode (see page 38).

as possible to try and reach the set points (V

SET

and I

) that were

SET

configured prior to enabling the output. Initially the unit will operate in CV mode, which is the default mode. As the voltage and current rise to meet the requirements of the load, the set point that is reached first (based on the R

, either V

SET

or I

) will determine which mode the

SET

power supply will remain in. The operating mode is indicated by either

CV and CC mode LEDs will not indicate the mode while the output is

Constant Voltage (CV) Mode Operat ion

If the output is enabled and the configured current set point is much higher than the requirements for the attached load, then the voltage will rise until it reaches the voltage set point. When the output voltage reaches the voltage set point, it stops rising. The unit will continue to operate in CV mode. The load current will still vary to meet any changes in required load current draw resulting from a change in the attached load.

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Constant Current (CC) Mode Operation

If the output is enabled, the v oltage and cu rrent st art to rise. A t t his t im e the un it is opera ting in CV mode (default operational mode). As the load current drawn reaches the value of the output current setting, the unit will switch to CC mode and not allow any additional current to be drawn above the value of I

. The unit is now operating in CC mode. The voltage will

SET

still vary to meet any changes in required output voltage resulting from a change in the attached load.

Constant Power (CP) Mode Operation

If the output is enabled, the voltage and current start to rise. The unit will con tinue to increase the current until one of the following occurs:

• The programmable power set point has been reached.

• The voltage set point has been reached, in which case the unit will regulate the voltage

in order to maintain the voltage set point.

• The current s et point has be en reached, in wh ich case the unit will regu late the current in order to maintain the current set point.

Figure 11: Voltage:Current:Constant Power Set Point

Automatic Mode Crossover

Mode crossover oc curs wh en th e unit m ak es the sw itch betwee n op erating m odes. Crossover can occur from CV to CC or vice versa, depending on how the attached load resistance changes. Figure 12 shows the relationships between the variables.

For example, if the unit was initially operating in CV mode with the output voltage at the voltage set point and the loa d current below the I

and the attached load resistanc e began to

SET

decrease, the current would rise to meet this change in the load. The load current will increase in proportion to the decrease in the load resistance until the load current drawn reaches the current set poin t. At this p oint fur ther decr eases in load res istance (inc reased loa d current requirements) will cause the unit to cross over into CC mode where the output voltage will vary with changing load resistance and the load current will remain at the I

value.

38 2268S-901-01 Rev. A / January 2015

SET

Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Important: If you can't get the set point to the desired level, you may need to change the set points for OVP.

Important: The control circuits have been designed to allow you to set the

specification is not guaranteed.

Quick Ti p: Remote

The SCPI command (s) for these instructions are:

[:AMPLitude]

The reverse operating mode change can also occur if the load resistance is increased to the point that the required load current drops below the I

value. At that point the power

SET

supply would crossover to CV mode and the load current would be free to vary as the load resistance changed.

Figure 12: Operating Modes

To set the voltage set point (V

1. Turn the 9-position mode control to the VOLTS position or press the rotary Adjust/Ente r con tro l if th e 9 -position mode control is already at the VOLTS position.

The voltage set point is blinking in the output voltag e display. The output current will be displayed in the output current display.

2. Set the desired voltage value using the rotary Adjust/Enter control.

3. Press the rotary Adjust/Enter control to transition to Fine Adjust mode. The set point will blink faster to indicate fine adjust tracking mode.

4. Set the desired voltage value using the rotary Adjust/Enter control.

5. Once the desired value has been set, press the rotary Adjust/Enter control to commit the setting.

output voltage up to 105% over the model-rated maximum value. The power supply will operate within these extended ranges, but full performance to

SET

operation uses these SCPI commands. See page 101.

2268S-901-01 Rev. A / January 2015 39

[[:]SOURce[<channel>]]:VOLTage[:LEVel][:IMMediate]

Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Important: The maximum and minimum setting values of the output voltage settings.

Important: The control circuits have been d esigned so that output current can

will operate within these extended ranges, but full performance to specification is not guaranteed.

are limited by the Over Voltage Protection and Under Voltage Protection

To set the current set point (I

SET

)

1. Turn the 9-position mode control to the AMPS position or press the rotary Adjust/Ente r con tro l if th e 9 -position mode control is already at the AMPS position.

The voltage set point is blinking in the output voltage display. The output current will be displayed in the output current display.

2. Set the desired current value using the rotary Adjust/Enter control.

3. Press the rotary Adjust/Enter control to transition to Fine Adjust mode. The set point blinks faster to indicate fine adjust tracking mode.

4. Set the desired current value using the rotary Adjust/Enter control.

5. Once the desired value has been set, press the rotary Adjust/Enter control to commit the setting.

be set up to 105% over the model-rated maximum values. The power supply

The SCPI command (s) for these instructions are:

[[:]SOURce[<channel>]]:CURRent[:LEVel][:IMMediate] [:AMPLitude]

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Series 2268 850 Watt DC Power Supplies Reference Manual Local Operation

Local Control Configuration

Additional References

Use the front panel controls to

See section on “Local Operation” on page 30

programming procedures.

The OVP set point is adjusted at

voltage.

See “Using Over Voltage Protecti on (OVP)” Important: The main output will not turn on i f the shutdown fu nction is

activated. See “Using the External Shutdown Function” on page 53.

Quick Ti p: Remote

101.

SHIPPED CONFIGURATION (LOCAL OPERATION)

The power supply is configured for local operation at the factory. See the table that follows for a summary of this configuration.

adjust the output voltage and current set point settings.

the front panel to 105% above the maximum rated output

ENABLING THE OUTPUT

Enabling the output on will also turn off the ALARM LED if the ALARM LED has been latched on due to an alarm triggering and au tomatically clea ring. See “Al arms and E rrors” on page 44.

To enable the output power:

♦ Press the OUTPUT ENABLE Main button on the front panel or enter the SCPI

To disable the output power:

♦ Press the OUTPUT ENABLE Main button when the OUTPUT ENABLE Main button

command. The OUTPUT ENABLE Main button will illuminate.

is illuminated.

for front panel operation. See section on, “Analog Programming & Isolated Analog Programming” on page 72 for analog

on page 50 for the adjustment procedure.

The output will be disabled and the LEDs will not be illuminated.

operation uses these commands. See page

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>][:POWer][:STATe]

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Important: The auxiliary output will not be enabled if the external

87.

ENABLING THE AUXILIARY OUTPUT

To enable on the auxiliary output:

♦ Press the OUTPUT ENABLE Aux butto n on the front panel .

The OUTPUT ENABLE Aux button will illuminate.

AUX_ON_OFF signal line is be ing used to disable the auxiliary outputs. See “AUX Output and Isolated Analog Programming (ISOL) Connector” on page

To disable the auxiliary output:

♦ Press the OUTPUT ENABLE Aux button on the front panel again. The OUTPUT

ENABLE Aux button will not be illuminated.

If the auxiliary output is activated, +5 V on J3.9 (+AUX1) and +15 V on J3.11 (AUX2) will be present with respect to Pin J3.2 or Pin J3.6 (COM ISOLATED). (See also “

Output and Isolated Analog Programming (ISOL) Connector

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:AUXiliary[:STATe]

AUX

” on page 87 for more details.)

OUTPUT AUTO START MODE (AUTO RESTART)

The Auto Start mode establishes the state of the output of the power supply after recovery from a complete power cycle (all front panel LEDs are not illuminated).

If Auto Start mode is set to On, the power supply output will return to its previous value when the power supply is powered up again.

If Auto Start mode is set to Off, the power supply output will remain off after the power supply is powered up again.

To change the Auto Start mode:

1. Press and hold the OUTPUT ENABLE Main button for 1 second. or

is displayed.

2. Switch the Auto Start mode.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>][:POWer][:STATe]:PowerON[:STATe]

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AUXILIARY AUTO START MODE

The Auxiliary Auto Start mode determines the state of the auxiliary output after a complete power cycle (all front panel LEDS are not illuminated). With Auxiliary Auto Start mode turned to On, the auxiliary output will be activated after the power supply is powered up again.

To define the Auxiliary Auto Start mode:

1. Press and hold the OUTPUT ENABLE Aux button for 1 second. or

is displayed.

2. To change to status to On or Off, press the OUTPUT ENABLE Aux button.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:AUXiliary:PowerON[:STATe]

CONSTANT POWER MODE

In Constant Power Mode the power supply will continually adjust the current levels to maintain a constant power set point. T his mod e is inten ded pr imarily fo r loads w ith respons e time greater than approximately 100m s. In order to p rovide additional pro tection for the load, voltage and current limits may be set while in the constant power mode. If the unit cannot regulate to the Constant Power setting due to load conditions, it will regulate at either the voltage or the current limit depending on the load demand.

Example, CP Mode:

Constant Power set 500W Voltage limit 61V Current limit 20A

To activate Constant Power mode and set the value:

1. Turn the 9-position mode control to the FLD position or press the rotary Adjust/Ente r cont rol if the 9 -position mode cont rol is already at the FLD position.

2. Turn the rotary Adjust/Enter control until “CP” is displayed.

3. Press the rotary Adjust/Enter control.

4. Turn the Adjust/Enter control to the desired set point.

5. Press the rotary Adjust/Enter control.

6. Turn the Adjust/Enter control for fine adjustment.

7. Press the rotary Adjust/Enter control to commit the Constant Power operation.

To disable Constant Power operation:

1. Turn the 9-position mode control to the FLD position or press the rotary Adjust/Ente r cont rol if the 9 -position mode control is already at the FLD position.

2. “FLD” is displayed on the output voltage display and the output current display shows the Constant Power mode “CP”.

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Alarm

Precedence

Output

Maskable

Display

AC Fail

1 (Highest)

Yes

Over Temperature Protection (OTP)

Yes

OtP

Fan 4 No

Yes

Interlock

In Loc

Over Voltage Protection (OV P)

Always

No Over Current Protection (OCP)

Always

No Foldback

Yes

Yes External Shutdown

Yes Under Voltage Protection (UVP)

11 (Lowest)

Yes

Current Loop Protection

12 (Lowest)

Loop Pro

Flash Checksum Failure

N/A

3. Turn the rotary Adjust/Enter control until “NONE” is display ed in the ou tp u t current display.

4. Press the rotary Adjust/Enter control to commit the setting once the desired value has been set.

5. The green FLD LED wi ll turn o ff and the display w ill return t o the norm al disp lay mode.

The SCPI command (s) for these instructions are:

[:]SOURce[<channel>]:POWer:MODe[:STATe] [:]SOURce[<channel>]:POWer:LEVel

ALARMS AND ERRORS

Several conditions can cause alarms in the POWER SUPPLY. Some conditions are:

• From user configurable features.

• Controlled in hardware and will trigger regardless of configuration.

All alarms, w ith the exception of the Fan alarm, will result in the output of the po wer supp ly being disabled. The Fan alarm does not affect the output.

When an alarm is triggered, the approp riate alarm messag e will begin blinking on t he display and the Alarm LED will be il luminate d. I t is poss ible th at m ore tha n one a larm will tr igg er at the same time. When this occurs, the alarm with the highest precedence will blink on the display.

The table that follows lists the precedence of alarms. If the alarm is cleared and the

event which caused the alarm has not been corrected, then the alarm may trigger again immediately. Fix the reason for the alarm before you clear it.

Latch

The Flash Checksum Failure alarms are an exception as they can only occur during boot up or recalling a user setting slot. If a check sum error is detected wh en recalling a user s lot, no m odif ication of settings will occur, and an error will be pushed to the SCPI error queue. If a checksum occurs at boot-up, then this checksum error can be cleared by doing a soft reset or by power cycling the unit.

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Important: When an alarm is cleared by using this method, only the current

now become the highest precedence alarm and will begin blinking on

the display.

CLEARING ALARMS

Clearing Triggered and Manual Alarms

To clear a triggered alarm, use one of the following methods:

• Turn the power supply Off and then On.

• Press and hold the rotary Adjust/Enter control for 3 seconds.

To clear a manual alarm:

1. Press and hold the rotary Adjust/Enter control for 3 seconds. The message will be displayed on the front panel for a few seconds.

highest precedence alarm is cleared. If another alarm has occurred, then this alarm will

2. Repeat the alarm clearing until you have cleared all alarms.

Clearing a Flash Failure Alarm

The Flash Failure alarm is the only exception for clearing alarms. If a flash failure occurs at boot time, it can only be cleared by a soft reset key combination press (see “Resetting the Power Supply” on page 62) or by power cycling the unit. If a checksum error is detected when recalling a user slot, no modification of sett ings will occur, and an error will b e pushed to the SCPI error queue. The alarm will clear after a duration per the currently configured front panel timeout setting.

To clear a triggered alarm, use one of the following methods:

• Turn the power supply Off and then On.

• For failures that occur during a recall of user memory settings, wait the duration of the

currently configured front panel timeout.

• Press and hold the res et key combination (Flash Fail ONLY). See “Resetting the Power

Supply” on page 62.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:PROTection:CLEar

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Clearing Automatic Alarms

Some alarms will clear automatically when the condition that caused the alarm is no longer present. When an alarm automatically clears, the output voltage and current displays will return to normal, but the ALA R M L E D w ill remain illum inate d to indicate that an alarm has occurred. If an automatic alarm is triggered, the normal alarm clearing procedure still applies.

To clear the ALARM LED after an automatic alarm has cleared, use one of the following methods:

• Send the SCPI Clear Alarm command.

• Press the OUTPUT ENABLE Main button to reenable the output. The ALARM LED

For example, if one of the fans was temporarily blocked, causing a Fan alarm, then the blockage was cleared and the fans restarted, the alarm would clear. The output voltage and current displays would be in normal mode, but the ALARM LED would be illuminated. See “Front Panel Alarm LED” on page 46 for information on other ev ents that affect the A LARM LED.

Alarms status is tracked in the SCPI status registers. For more details on how and where the alarms are tracked, see “Standard SCPI Register Structure” on page 134.

will no longer be illuminated.

Front Panel Alarm LED

The Alarm LED will illuminate due to one or more of the following events occurring:

• OTP has been tripped.

• A fan has stopped.

• OVP has tripped.

• OCP has tripped.

• UVP has tripped

• Interlock is open circuit.

• AC power falls out of range.

• Foldback has tripped.

• Persistent storage checksum is wrong (Flash Fail alarm).

• Internal malfunction of power supply.

• Any alarm has tripped and been cleared automatically.

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Alarm

Bit Position

Value

Over Temperature Protection (OTP)

2 2

Not used

3 4

Fan 3 8

Foldback

256 External Shutdown

512 Under Voltage Protection (UVP)

1024

The alarm LED will remain illuminated until the alarm is manually cleared (see “Clearing Triggered and M anual A larm s” on pag e 45) or by turning the m ain output on if the al arm has automatically been cleared.

Alarm Masking

It is possible to completely disable some alarms through the use of the alarm mask. If an alarm is masked then this masking will prevent it from registering in the SCPI conditions registers as well as not triggering the alarm. The alarms that can be masked are identified in the table on page 44. Setting the bit position (1) of an alarm will result in the alarm being enabled. Clearing the bit position (0) of an alarm will result in the alarm being masked/disabled.

For Example: If you wanted to enable the OTP, Foldback and UVP alarms, you would take the foldback value of 256 and the UVP value of 1024 to get a mask of 1280. This is the value you would send with the SCPI command.

Control of the alarm mask is only available using the SCPI command.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel>]:PROTection:MASK

The mask command tak es a single param eter made u p of the sum of the values for the ala rms that are to be masked. See the table that follows for the alarm values associated with each maskable alarm.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel>]:PROTection:MASK

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Alarm

Bit Position

Value

AC Fail

Over Temperature Protection (OTP)

Foldback

256

Alarm Output Latching

When an alarm is triggered, the output will be disabled with the exception of the Fan alarm. When an alarm is cleared, the alarm output latch determines if the output should be re-enabled to the state before the alarm occurred or if the output should remain in the off state.

Where setting the bit position (1) of an alarm latch will result in output latching to the off state when the alarm is c lea red an d if c le a red (0) output w il l b e re-enabled to the state b e fore the alarm triggered.

To define the values for the bit position you determine which alarms y ou want to latch. Read the value for this bit position from the table th at follo w s and sum them together. The result is the alarm last mask, which you should send with the SCPI command.

For Example: If you wanted to enable latching for OTP and Foldback you would take the OTP value of 2 and add it to the foldback value of 256 to get a m ask of 258. This is the v alue you would send with the SCPI command.

The output latches are accessible through the SCPI command.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel>]:PROTection:LATCh

The latch comm and take a s ingle d ecim al param eter m ade up of the sum of the valu es for the alarms to determine if they are to be latched in the off state on clearing. See the following table for the values associated with each latchable alarm.

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Important: If you set f ol dback whi l e th e ou t put is en abl ed a n d t h e t rig g er you counting immediately after the delay time has been set.

SETTING FOLDBACK MODE

Foldback mode is used to disable the output when a tran sition is m ade between the operati ng modes. The power supply will turn off/disable the output and lock in foldback mode after a specified delay if the power supply t ransitions into C V m ode or into C C m ode, depending on the foldback mode settings. This feature is particularly useful for protecting current or voltage sensitive loads. Fold back can be set to trigger a switch w hen transitioning from CV to CC mode or from CC to CV mode.

To set the foldback protection and foldback delay time:

1. Turn the 9-position mode control to the FLD position or press the rotary Adjust/Ente r cont rol if the 9 -position mode cont rol is already at the FLD posi tion .

2. Select the type of crossover that will cause foldback to trigger by using the rotary Adjust/Enter control.

If the mode selected is CC or CV mode, the foldback delay timer will start on a transition into the selected mode. If the mode selected is none, foldback is not enabled.

3. Press the rotary Adjust/Enter control when the desired mode has been selected. The FLD LED will illuminate and will be disp layed in the o utput v oltag e disp lay.

4. Adjust the desired delay time using the rotary Adjust/Enter control. The range can be set from 0.50 seconds to a maxim um of 50 seconds. The s tep size is in

increments of 0.05 seconds when setting from 0.50 to 5 seconds and then in 1 second increments from 5 seconds to 50 seconds.

5. Once the desired foldback delay time has been selected, press the rotary Adjust/Enter control to commit the foldback delay setting.

To disable foldback protection:

1. Turn the 9-position mode control to the FLD position or press the rotary Adjust/Enter control if the control knob is already at the FLD position.

2. is displayed on the output voltage display and the output current display shows the current foldback trigger mode.

3. Turn the rotary Adjust/Enter control until is displayed in the output current display.

4. Press the rotary Adjust/Enter control to commit the setting once the desired value has been set.

5. The green FLD LED wi ll turn o ff and the display w ill return t o the norm al disp lay mode.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:PROTection:FOLDback[:MODE] [:]OUTPut[<channel>]:PROTection:FOLDback:LATCh

select is the same as the current operating mode, the foldback timer will begin

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Local Operation Series 2268 850 Watt DC Power Supplies Reference Manual

Important: The OVP range is variable from V

SET

+5% to V

MAX

+25%.

RESETTING ACTIVATED FOLDBACK PROTECTION

To reset activated and latched foldback protection, press and hold the rotary Adjust/Enter control for approximately 3 seconds.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:PROTection:CLEar

USING OVER VOLTAGE PROTECTION (OVP)

The OVP circuit protects the load in the event of an analog programming error, an incorrect voltage control adjustment, or a power supply failure. The OVP circuit monitors the output voltage at the output of the power supply and will disable the output whenever a preset voltage set point is exceeded. You can set the preset voltage trip point by using the 9-position mode control on the front panel or via one of the remote programming interfaces.

To prevent accidental tripping of the OVP while setting up, the firmware will prevent the OVP set point from being less than 105% of the voltage set point when in local set point control mode. When the power supply is in VAP mode for defining voltage set point the set point limitation will be based on the VAP input signal level. The user should note it is possible to trip OVP in this mode if the OVP is configured when the analog programming source is off.

When the user attempts to configure an OVP setpoint that is less than 105% of the voltag e set point via the front panel the set point will stop allowing the value to decrement. If the user attempts to configure an OVP set point that is less than 105% of the voltage set point via SCPI a -221, “settings conflict error” will be pushed onto the error queue.

Defining the OVP Set Point

To define the OVP set point:

1. Turn the power supply On. Ensure the voltage is lower than the desired set point.

2. Set the output to the desired voltage. OVP can be set without setting desired output voltage first.

3. Turn the 9-position mode control to the PRT position. Προ ΟΥΠ is displayed.

4. Press the rotary Adjust/Enter control.

5. Turn the rotary Adjust/Enter control to set the upper limit protection. See “Coarse and Fine Adjustment Modes” on page 31.

6. Once the desired value has been set, press the rotary Adjust/Enter control to commit the setting.

The SCPI command (s) for these instructions are:

[[:]SOURce[<channel>]]:VOLTage:PROTection[:OVERvoltage] [:LEVel]

If the output is between OVP APG mode.

and -5%, an OVP warning message is possible when in

set

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Important: UVP will not be active for voltage set points that are less than 1% of model voltage.

Important:

The UVP range is variable from 0 volts to OVP

SET

-10%.

USING UNDER VOLTAGE PROTECTION (UVP)

The UVP prevents voltage settings below a set value. The UVP lets you create a voltage window of operation when used in conjunction with the OVP setting. The UVP range is variable from 0 V to OVP

The UVP is a protection that becomes active after the output is enabled and a period of time has passed to allow the output to reach its set point value before the UVP protection begins monitoring. As with OVP if the v oltag e se t poin t is dete rm ined by ana log con trol ( VAP) an d the voltage strays to within 5% of the UVP set point then UVP Safe will trigger to warn the user that they are about to trigger the UVP alarm.

The period of time before the UVP monitoring is active after the output is enabled is determined by the rise-time delay for the model. Since the rise time is based on a purely resistive load the use r shou ld be awar e that U VP trigg ering m ight be possib le in cap acitive or rectifier lo ads due to the ris e time being longer. I n these cases it is recomm ended that the user mask the UVP alarm until the r ise tim e has elapse d and then unm ask the alarm to allow U VP protection to be enabled during operation.

-10%.

SET

Defining the UVP Set Point

To define the UVP set point:

1. Turn the power supply On.

2. Set the output to the desired voltage.

3. Turn the 9-position mode control to the PRT position. is displayed.

4. Turn the rotary Adjust/Enter control until is displayed.

5. Press the rotary Adjust/Enter control to select the UVP for setting up.

6. Set up the lower limit protection using the rotary Adjust/Enter control.

7. Once the desired value has been set, press the rotary Adjust/Enter control to commit the setting.

See “Coarse and Fine Adjustment Modes” on page 31.

The SCPI command (s) for these instructions are:

[[:]SOURce[<channel>]]:VOLTage:PROTection:UNDer[:LEVel]

OVER CURRENT PROTECTION (OCP)

The OCP alarm is a firmware alarm that is only configurable using the SCPI interface. The OCP triggers if the output current exceeds the OCP set point. Because the OCP alarm is a firmware based alarm it has a latency before detection of the condition can occur. The user should be aware of this latency and take this into consideration when relying on OCP to protect a sensitive load. The maximum period for detecting an OCP condition is 300 ms.

OCP is fixed at 110% of rated current.

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USING OVER TEMPERATURE PROTECTION LOCK (OTP)

The OTP lock protects the power supply in the event of an over temperature alarm. This alarm could be caused by ventilation restriction or overheating due to fan failure.

Two modes are available:

• Auto recovery (OTP OFF) where the power supply turns on again after cooling down.

• Latch mode (OTP ON) where you will need to reset the unit by turning the front panel

power switch to Off and then On again.

If the OTP is activated, the main output will turn off and protection) will blink on the display. The OTP a larm is an alarm that will auto recov er w hen the temperature falls back into normal bounds.

Defining the OTP Mode

To define the OTP lock:

1. Turn the 9-position mode control to the PRT position. PrO OUP is displayed.

2. Turn the rotary Adjust/Enter control until is displayed.

3. Press the rotary Adjust/Enter control to display .

4. Turn the rotary Adjust/Enter control to change to On or Off.

5. Press the rotary Adjust/Enter control.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel(s)>]:PROTection:LATCh

Resetting in Latch Mode

To reset the powe r supply if the OTP alarm is t ripped and th e OTP m ode is set to On ( latching enabled), press and hold the rotary Adjust/Enter control for approximately 3 seconds.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel(s)>]:PROTection:CLEar [:]SYSTem[<channel(s)>]:PROTection:LATCh

(over temperature

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USING THE EXTERNAL SHUTDOWN FUNCTION

Use the external shutdown function to enable or disable the outpu t of the pow er su pply v ia a logic level signal. Wh en the external shutdown is triggered, the power supply will display SD POL on the output voltage and current displays. The external shutdown is useful for making adjustments to either the load or the power supply without shutting off the power supply or for using the power supp ly as pa rt of a larg er tes t syste m in which dig ital or ana log control is required.

Activating the External Shut down Function

To activate the external shutdown function, use the AUX output supply provided on the Analog Programming Connector J3. This input has a user selectable polarity with logic low input from 0.0V to 1.2V and logic high from 2.0V to 15V. The control signal for this input must be capable of sinking 10mA minimum. This input is also compatible with the use of dry contacts, where a short is logic low and an open is logic high. The input lines of the shutd own circuit are fully optically isolated.

Once the External Shutdown has been triggered, the display will blink the .

Controlling the Exter na l S hut down Function

The external shutdown circuit accepts a voltage or dry contact control (high or low logic level) to enable or disable the power supply output. Make connections for the signals at the AUX Output and Isolated Analog Programming Connector on the rear panel. (See “AUX Output and Isolated Analog Programming (ISOL) Connector” on page 87 for more information.)

To activate the shutdown function:

Connect the control signal source to the Shutdown pin (J3.12) on the Aux Output and Isolated Analog Programming Connector with the control circuit ground connected to Isolated Ground pin (J3.6).

The External Shutdown pin is pulled high internally (normally high). Therefore, if this feature is not used, the polarity should be set to 1 to avoid false triggering. (See “D efining the Polarity of the External Shutdown Signal” on page 54 for instructions.)

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Important:

There is an internal pullup resistor inside the shutdown circuit so

the shutdown polarity should be set to 0 if it is not being used.

Important:

While Loop Protection is enabled (ON), the external shutdown

setting.

Defining the Polarit y of the Exter na l Shutdown Signal

1. Turn the 9-position mode control to the PRT position or press the rotary Adjust/Enter control if the control knob is already at the PRT position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control until is displayed.

3. Press the ro tary Adjust/En ter con trol to d isplay (shutdown on logic 0) or (shutdown on logic 1).

4. Press the rotary Adjust/Enter control to commit the desired polarity setting. For example: If you set the shutdown logic to 1 ( ) and apply a logic high (greater

than 1.2 Vdc) to pin J3.12 relative to pin J3.6 on the ISOL connector, the power supply will shut down. Conversely, if you se t the shutdown lo g ic to 0 ( will only operate when you have a logic high (greater than 1.2 Vdc) to pin J3.2 relative to pin J3.6.

The SCPI command (s) for these instructions are:

[:]OUTPut[<channel>]:POLarity

), the power supply

LOOP PROTECTION

The Loop Protection feature can be used to enable or disable multiple units in daisy chain configuration through the AUX Output and Isolated An alog Programming Connector, J3. Up to four units (example, Units #1 through #4) can be configured in Loop Protection; if one of the units is experiencing a fault condition, other units in the same loop will disable their output simultaneously. This is achieved by connecting Unit #1’s MAIN_PS_GOOD to Unit #2’s SD (Shutdown Main O/P) and continues until Unit #4’s MAIN_PS_GOOD is fed to Unit #1’s SD (Shutdown Main O/P). Common applications include s ingle master controlling multiple slave units as a sy stem O n/Off. In addition, any fault from either o peratin g unit wil l cause the system to disable.

The Loop Protection can be enabled o r disabled locally using the front panel 9-position m ode control, or remotely using a SCPI command.

function will be automatically set to low active. When Loop Protection is disabled (OFF), the external shutdown function will be set to the user’s last

Setting up Loop Protecti on

To set up Loop Protection:

With the AC powered OFF, connect the first unit’s pin J13.13 to the next unit’s J 13.12 on the AUX Output and Isolated Analog Programming Connector. Do this for up to four units. An example of a 3-unit loop protection is illustrated as follows:

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Figure 13: Loop Protection Setup

To enable or disable Loop Protection:

1. Turn the 9-position mode control to the PRT position. PRO OVP is displayed.

2. Turn the rotary Adjust/Enter control until LOOP PRO is displayed.

3. Press the rotary Adjust control to display LOOP ON or OFF.

4. Press the rotary Adjust control to change the setting to ON or OFF.

5. Press the rota ry Adjust con trol to accep t the chang e.

The SCPI command (s) for these instructions are:

[:]OUTPut [<channel>]:PROTection:Loop[:STATe]

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INTERLOCK FUNCTION

The Interlock function can be used to wire an external shutoff switch that can be used to enable or disable the power supply output. When the switch is closed, the power supply will operate normally. If the switch is opened, the power supply will trigger the interlock alarm. The output will be disabled, the display will blink illuminate. This alarm will automatically clear when the switch closes again, and the output will autom atically be res tored to its pr e-alarm state (either en abled or di sabled). Th e interlock function can only be enabled or disabled (defined) using a SCPI command (cannot be masked or latched through the alarm protection mechanisms.). C ommon applications include an emergency shutoff switch or a door switch.

Connect the switch between pins J3.14 and J3.15 on the AUX Output and Isolated Analog Programming Connector.

Defining the Interlock Mode

The Interlock mode is controlled via SCPI commands. There is no front panel access for enabling or disabling the Interlock functionality. See “Interlock Enable/Disable” on page

161.

The SCPI command for setting the Interlock mode to On or Off is:

[:]SENSe[<channel>]:PROTection:INTerlock[:STATe]

, and the ALARM LED will

OUTPUT PROTECTION

The output voltage and the output current can be programmed (preset) to automatically start at zero Volts and zero Amps upon power-up and upon output enable. Also, each can be reprogrammed to disable the automatic reset to zero.

Programming Voltage Output Pre s e t

To Enable/Disable automatic reset to 0 Volts:

1. Turn the rotary Adjust/Enter control to PRT and press.

2. Turn again until is display ed.

3. Press to display .

4. Turn to display or .

5. Press to commit the selected setting.

Important: This single front panel operation affects both power on and output enable. However, when using SCPI, there is a separate command for each.

The SCPI command to query or enable/disable the 0 Voltage Output Preset at power-on is:

[:]SYSTem[<channel>]:PON:VOLTage {?|ON|OFF}

The SCPI command to query or enable/disable the 0 Voltage Output Preset upon output enable is:

[:]SYSTem[<channel>] :PON:ENAble:VOLTage {? |ON|OFF}

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Programming Current O ut put Pr e set

To Enable/Disable automatic reset to 0 Amps:

1. Turn the rotary Adjust/Enter control to PRT and press.

2. Turn again until is displayed.

3. Press to display .

4. Turn to display or .

5. Press to commit the selected setting.

Important: This single front panel operation affects both power on and output enable. However, when using SCPI, there is a separate command for each.

The SCPI command to query or enable/disable the 0 Current Output Preset at power-on is:

[:]SYSTem[<channel>]:PON:CURRent {?|ON|OFF}

The SCPI command to query or enable/disable the 0 Current Output Preset upon output enable is:

[:]SYSTem[<c hannel>] :PON:ENAbl e:CURRent {? |ON|OFF}

POWER ON STATUS SIGNAL

Power On Status signal indicates a fault condition in the power supply. Power On Status signal is a TTL output signa l at Pin J2.13 wi th reference to CO M ISOLATED (Pin J2.2 or Pin J2.6).

During normal operation, the Power On Status signal will be high. If the output is disabled for any reason, the Power On Status signal will go low.

The following conditions will set the Power On Status to a low level:

• AC fail

• Current Loop Protection

• Over Voltage Protection (OVP)

• Under Voltage Protection (UVP)

• Over Current Protection (OCP)

• Over Temperature Protection (OTP)

• Foldback Protection

• Interlock

• Output Off

• Shutdown activated (rear panel shutdown).

• Internal hardware malfunction Fan failure

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Voltage Setpoint

Current Setpoint

Voltage Output Protection

Current Output Protection

Over Voltage Protection (OV P)

Under Voltage Protection (UVP)

Over Temperature Protection (OTP)

Autostart OUTPUT ENABLE Main

Autostart OUTPUT ENABLE Aux

Foldback Mode

Foldback Delay

Shutdown Logic

Voltage Analog Programming (VAP) Mode

Voltage Analog Programming (VAP) Level

Current Analog Programming (CAP) Mode

Current Anal og Programming (CAP) Level

Remote Programming Interface

Local Lock

PSU (Power Supply) Address

Data Rate (BPS)

Alarm Latches

Front Panel Timeout

Constant Power Mode

Constant Power Level

Loop Protection Enable

Line Drop Mode Settings

HARDWARE MALFUNCTION ALARMS

The power supply will turn off the output. An error message will be displayed in the event that:

• OVP trips

• Voltage deviation in CV mode reaches more than ±5% from the set level.

• Current deviation in CC mode reaches more than ±5% from the set level.

__________________________

1. These two forms of hardware malfunction are only monitored in the corresponding APG mode.

CURRENT CONFIGURATION MEMORY SETTINGS

The power supply will save the u nit settings at the tim e of power down. These settings will be loaded when the power is restored to the unit or the power supply is powered up again. The table that follows lists the settings that are saved and recalled on a power cycle event.

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Voltage Setpoint

Current Setpoint

Voltage Output Protection

Current Output Protection

Over Voltage Protection (OVP)

Over Temperature Protection (OTP)

Autostart OUTPUT ENABLE Main

Autostart OUTPUT ENABLE Aux

Foldback Mode

Foldback Delay

Shutdown Logic

Voltage Analog Programming (VAP) Mode

Voltage Analog Programming (VAP) Level

Current Analog Pro gramming (CAP) Mode

Current Anal og Programming (CAP) Level

Current Sharing Mode

Alarm Latches

Front Panel Timeout

USER SETTING MEMORY LOCATIONS

There are three user setting memory locations available for storing frequently used configurations. These user setting memory locations help to facilitate multiple users of a Series 2268 power supply who have different setups or when multiple loads are used that have different requirem ents. The table that f ollows list s the valu es that a re stored in each user setting memory location.

Saving User Setting Memory Locations

To save user setting memory locations:

1. Turn the 9-position mode control to the SAV position.

is displayed on the output voltage display with a number indicating a preset

position which is displayed on the output current display.

2. Turn the rotary Adjust/Enter control to select a preset position from 1 to 3.

3. Press the rotary Adjust/Enter control.

done is displayed on the output voltage display.

4. The setting has now been saved to the selected user setting memory location.

The SCPI command (s) for these instructions are:

*SAV <setting_location>

[:]SYSTem[<channel>]:SAVE <setting_location>

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Recalling User Setting Me m ory Locations

This feature recalls settings that were previously saved.

To load user setting memory locations:

1. Turn the 9-position mode control to the RCL position.

is displayed on the output voltage display w ith a number indicating a preset position

on the output current display.

2. Turn the rotary Adjust/Enter control to select a preset position from 1 to 3.

3. Press the rotary Adjust/Enter control.

is displayed on the output voltage display.

The settings in the s el ected user se tting m em ory locatio ns have now been app lied to the power supply.

The SCPI command (s) for these instructions are:

*RCL <setting_location>

[:]SYSTem[<channel>]:RECall <setting_location>

Three user setting memo ry locations a re avai lable and one u ser set ting m em ory loca tion is saved automatically before AC power shutdown. This user setting memory location will be loaded after AC power is restored.

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LOCAL LOCKOUT

Local lockout is a feature that allows the front panel to be locked so that accidental button presses are ignored. This feature is often used to lockout the front panel when you are controlling the power supply from a remote location. When in local lockout mode, the front panel will display

Enabling Local Lockout

To enable local lockout:

1. Turn the 9-position mode control to the PGM position or press the rotary Adjust/Enter control if the control knob is already at the PGM position.

The display will show in the output voltage disp lay and the select ed remote in terface in the output current display.

2. Turn the rotary Adjust/Enter control until the display shows .

3. Press the rotary Adjust/Enter control.

4. Turn the rotary Adjust/Enter control until the display shows .

5. Press the rotary Adjust/Enter control. Local lockout has been enabled.

Loc whenever a button is pressed or a knob is turned.

The SCPI command (s) for these instructions are:

[:]SYSTem:REMote:STATe

Disabling Local Lockout

To disable local lockout:

1. Turn the 9-position mode control to the PGM position or press the rotary Adjust/Ente r con tro l if the control knob is already at the PGM position.

The display will show in the outp ut voltage d isplay and the selected r emote in terface in the output current display.

2. Turn the rotary Adjust/Enter control until the display shows .

3. Press the rotary Adjust/Enter control. Local lockout will be disabled after power-cycling the power supply.

The SCPI command (s) for these instructions are:

[:]SYSTem[<channel(s)>]:REMote:STATe

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The reset is used to clear the parameters to the factory defau lt values.

Soft Reset

The soft reset is used to set the parameters (see table below) to the

Parameter

Setting

Address

Data rate (Kbps)

9.6

Communication mode

RS-232

Vout setting

0 V

Iout setting

0 A

Output

Off

AUX Out

Off

Trigger

Off

Ext. On/Off Polarity

Negative

Auto start mode

Off

AUX Auto start mode

Off

OVP

Maximum

UVP

0 V

Foldback trigger

None

Foldback delay

0.5 s

Current Share Mode

Controller

Alarm Output Latches

263 (0 x 107, all latches enabled)

Alarms Mask

2047 (0 x 7FF, all enabled)

Interlock

Disabled

Voltage Analog Programming

Off

RESETTING THE POWER SUPPLY

default values, but it does not reset the calibration constants

To perform a soft reset:

1. Turn the power supply to Off then On. When the unit is powering on, is displayed on the output v oltage and current

displays.

2. Press the key com bination of both OUTP UT ENABLE Main bu tton and OUTPU T ENABLE Aux button and hold continuously for 3 seconds in order to execute.

If the flash fail alarm triggers, it is also possible to reset the power supply. The front panel should display

3. Once a reset has been triggered, the output voltage display shows for 1 second.

The model number will be displayed for 1 second and then return to normal mode.

After executing a reset, the power supply's settings are restored to the default settings but retain the calib ra tio n da ta . F ollo w in g lis ts the default settings.

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Parameter

Setting

Voltage APG Scale

10 V

Current Anal og Programming

Off

Current APG Scale

10 V

Voltage Output Protection

Off

Current Output Protection

Off

greater than 40V or a combin ed output of greater th an 40V. To protec t person nel

The remote programming inputs are internally referenced to the power supply's

utput. Do not con nect re m ote prog ramm ing ground li nes to th e pow er

USING MULTIPLE POWER SUPPLIES

WARNING: Shock hazard

There is a shock hazard at the load when using a power supply at an output of

against accidental contact with hazardous voltages created by a series connection, ensure that the load, including connections, has no live parts which are accessible. Also ensure that the insulation rating of the load wiring and circuitry is greater than or equal to the maximum or combined output voltage the power supply.

CAUTION: Equipment damage

Do not connect power supplies from different manufacturers in parallel or in series.

CAUTION: Equipment damage

negative o supply's positive output.

You can operate power supplies of the same model with the outputs in series to obtain increased load voltage or with the outputs in parallel to obtain increased current, also called current sharing. Bipolar supply operation gives you two positive outputs, or a positive and a negative output. When using multiple supplies in series or parallel, they will not meet the single unit specifications in this Manual.

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Figure 14: Bipolar Supply Operation

CONFIGURING MULTIPLE SUPPLIES FOR SERIES OPERATION

A maximum of two power supplies of the same rating can be connected in series to increase the output voltage.

CAUTION: Equipment damage

When two power supplies are connected in series, they should be programmed to the same output voltage to pre vent damage to the lower voltage supply at short circuit condition.

Load Considerations

CAUTION: Equipment damage

Use properly rated diodes to protect the power supply from damage while driving inductive loads..

INDUCTIVE LOADS: To prevent damage to the power supply from inductive kickback, connect a diode (rated at

greater than the supply’s output voltage and current) across the output. Connect the cathode to the positive output and the anode to return. Where positive load transients m ay occur, such as back EMF from a motor, a second diode in series with the output is recommended to protect the power supply.

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BLOCKING and FREE WHEELING DIODES: The Peak Reverse Voltage ratings should be a minimum of 2-3 times the power supply

maximum output voltage. The Continuous Forward Current rating should be a minimum of

1.5 times the power supply maximum output current. Heatsink may be required. There also

may be a need for hi gher vol tage rat ed pa rts , depe nde nt o n loa d cir cuit desi gn a nd in duct or values.

Connecting to the Load in Local Sensing Mode

Connect the negative (-) output terminal of one power supply to the positive (+) output terminal of the next power supply. See Figure 15 for a representation of series operation.

Figure 15: Series Operation

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Connecting to the Load in Rem ot e Sensing Mode

Connect the negative (-) output terminal of one power supply to the positive (+) output terminal of the next power supply. The more positive su pply's positive sense line should connect to the positive terminal of the load (or distribution point). Its return sense line should connect to the connection between the two units at the same spot as the negative supply's positive sense line. The return sense line of the negative supply should be connected to the return of the load. See Figure 16.

CAUTION: Equipment damage

Do not connect sense lines through relays.

Figure 16: Load Connections in Remote Sensing Mode

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Important: If current sharing is not being used, the unit must be configured as

a controller. Failure to do so will result in unpredictable operation.

CONFIGURING MULTIPLE SUPPLIES FOR CURRENT SHARING OPERATION (APG METHOD)

Up to four power supplies can be conne cted in para llel to incr ease t he outpu t curr ent. One of the units will operate as the master unit and the remaining units will operate as slave units controlled by the master unit. The master unit uses the analog programming lines to set the output voltages and currents of the slave units to match its output.

In remote digital operation, only the master unit can be programmed remotely while the s lave units that are connected remotely will only provide voltage, current and status readback information.

In APG current sharing topologies, only the master unit can be prog rammed using any of the input methods (front panel, remote digital, or analog prog ramming control). The slave unit(s) voltage and current output(s) are determined by the master unit through the REF_I input to each slave unit. The read back using any of the monitoring m ethods (front panel display, us er monitor lines or SCPI measure commands) of each unit (master or slave) will provide individual unit status, not system status.

Setting up the Controll er Uni t

Set the output voltag e of th e master unit to the desired v oltag e. Prog ram the current set point of the master unit to the desired load current set point divided by the number of p arallel units. During operation, the master unit operates in Constant Voltage mode, regulating the load voltage at the programm ed outpu t voltag e. Send the C urren t share SC PI comman d or use the following instructions to program front panel current share setup:

1. With the 9-position mode control at the PGM position, press the rotary Adjust/Enter control.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select and press the Adjust/Enter control.

is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select in the output current display.

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Important: The slave unit discussed here is not the same as the remote

interface slave described in section 5.

4. Press the rotary Adjust/Enter control to commit the setting.

The SCPI command (s) for these instructions are:

[[:]SOURce[<channel>]]:COMBine:CSHare[:MODE]

Setting up the Slave Units

The output voltage and current of the slave units should be programmed to maximum value. During parallel operation, the slave un its operate as a c ontrolled curren t source following th e controller unit's output current.

All slave units must be configured with the SCPI command to enable current sharing, or use the following instructions to program front panel current share setup:

1. With the 9-position mode control at the PGM position, press the rotary Adjust/Enter control.

is displayed on the output voltage display.

2. Turn the Adjust/Enter control to select “ ” and press the Adjust/Enter control.

is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select in the output current display.

4. Press the rotary Adjust/Enter control to commit the setting.

The SCPI command (s) for these instructions are:

[[:]SOURce[<channel>]]:COMBine:CSHare[:MODE]

Setting Over Voltage Protection (OVP)

The master unit's OVP should be programmed to the desired OVP level. The OVP of the slave units should be programmed to a higher value than the master OVP. When the controller unit shuts down, it will program the outputs of the slave units to zero volts. If a slave unit shuts down, only that unit would shut down and the remaining slave units would supply all the load current if possible.

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MASTER PSU

To other slaves

SLAVE PSU

Shielded Twisted Pair Out

Out

LOAD

Setting Foldback Protection

Foldback protection is only available on the master units as the slaves operate in constant current mode. They should never crossover into constant voltage mode. If foldback is triggered on the master unit, when its out put shuts dow n, it will p rogram the slave unit's output to zero volts.

CONNECTING TO THE LOAD IN LOCAL SENSING MODE (PARALLEL CONTROL METHOD)

Connect the power supplies in parallel to obtain a single output supply with a higher output current set point. Set al l of the ou tpu ts to the sa m e v oltage before conn ecting the positive (+) and negative (-) terminals in parallel. The total current available is the sum of the maximum currents of each power supply.

Figure 17: Load Connections in Local Sensi n g Mode

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MASTER PSU

To other slaves

SLAVE PSU

Shielded Twisted Pair

Out

LOAD

CONNECTING TO THE LOAD IN REMOTE SENSING MODE (PARALLEL CONTROL METHOD)

Figure 18: Load Connections in Remote Sensing Mode (Par allel Control Method)

POWER SAVING CONTROL (SLEEP MODE)

The Sleep Mode, supported by Series 2268 p ower supplies, is an effective way to reduce overall power consumption when the power supply is not in use fo r a specified period of time. If Sleep Mode is enabled, the power supply will revert to a low power consumption mode with the followi ng characteristics :

• Display will be blank.

• The internal cooling fans will run at the lowest possible speed for whisper-quiet

operation.

• Touching any button or one of the rotary knobs will immediately wake up the power

supply to normal mode of operation.

• All settings wil l be pre se rved during sleep m ode and the power supply will return to the

previously set state when it wakes up.

The following conditions must be met in order for Sleep Mode to engage:

• The output of the power supply and auxiliary outputs must be off (standby).

• The Sleep Mode must be enabled (on).

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Important: Sleep Mode is controlled only from the front panel.

To enable Sleep Mode: Set a time delay for the d uration of in activity to ela pse before enter ing Sleep Mod e. This tim e

(sleep hold-off delay) can be set from the Protection menu, under the SLP entry. The sleep hold off delay can be set from 1 to 9 hours.

To disable the Sleep Mode: Set the sleep hold off delay v alue to zero (0). Th is is also the def ault state for the Sleep Mode

feature. Thus, unless set from the front panel, Sleep Mode is of f. Once enabled (set to a valu e from 1 to 9), it will be enabled. If the set time elapses without any activity on the power supply, it will enter Sleep Mode.

Note that after issuing a *RST command, the power supply will revert to factory default settings, which means Sleep Mode will be turned off.

To set up Sleep Mode:

1. Turn the 9-position Mode Control switch to the PRT (protect) position.

2. Turn the Rotary Adjust/Enter k nob until the Output Current Display show s "SLP."

3. Press the Adjust/Enter button. The most recent setting for the Sleep Mode is displayed (a number from 1 to 9).

4. Turn the Rotary Adjust/Enter knob until the desired inactivity delay time is displayed.

5. Press the Adjust/Enter button.

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Analog Programming & Isolated Analog Programming

In this section:

This section provides information and procedures for analog and isolated analog programming of the power supply.

INTRODUCTION

The rear panel connectors J1 and J3 provide an option to control and monitor the output of the power supply with analog signals. Connector J1 pr ov ides a non-isol at ed an alo g inter face where all signals are referenced to the negative output terminal of the power supply. Connector J3 is an iso lated int erface and a lso p rovides an isolated auxiliary voltage output to aid analog programming.

Section 4

ANALOG PROGRAMMING (APG) OF OUTPUT VOLTAGE AND OUTPUT CURRENT

Analog programming allows control of the power supply's output voltage, output current or both to be controlled from analog input sources. As the prog ramm ing so urce is vari ed within the configured analog programming range (2-10 volts/kΩ max), the power supply's output varies proportionally over its output range. For example, if you set the program m ing scale to 10 V voltage source and apply 5 V to the programming pins, the power supply will be programmed to 50% of the output capability for your power supply.

While analog programming mode is conf igured, y ou wi ll not be a ble to make adjustments to the set points from the front panel or through the remote interfaces.

The front panel will display AnPr in the output current display when the 9-position mode control is turned to VOLTS or AMPS pos itions for the param eter(s) that are config ured to b e controlled by analog programming. If an adjustment of a parameter controlled by APG is attempted using a SCPI command, a “-221 Settings Conflict” error will be pushed onto the error queue.

Using analog programming requires that you make connections to the Isolated Analog Programming Connector or Analog Programming Connector on the rear panel of the power supply.

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Related APG Mode

Reference Line

Connector

Non-Isolated Volt a ge Ana lo g P ro gr ammi ng

VOL_MON

J1.13

Isolated Voltage Analog Pro gramming

IS_MON_VOL

J3.5

Non-Isolated Curr e nt Analog Programming

CUR_MON

J1.14

Isolated Current Analog Programming

IS_MON_CUR

J3.10

Important: Analog control monitor lines will re flect the output of the power

supply even when the unit is not set to operate in analog programming mode.

Important: Isolated monitor lines are only valid when isolated analog

isolated APG is used, these values will

APG is used, the non-isolated monitor lines will b e inaccurate.

Control of...

Programming Scale1

For more info…

Output voltage

2-10 V Voltage source (adjustable)

See page 77.

Current set point

2-10 V Voltage source (adjustable)

See page 79.

Output voltage

2-10 kΩ Resistive source (adjustable)

See page 82.

Current set point

2-10 kΩ Resistive source (adjustable)

See page 84.

REMOTE PROGRAMMING OPTIONS

Analog Monitor Signals

There are four monitor lines for analog programming the pin name and the related APG mode, which are listed in the table that follows. All of these l ines are prov ided to give analog feedback. The output from these monitor lines is a value scaled to the Analog Programming level set for the corresponding analog programming type. For example, the voltage monitor and isolated voltage monitor lines are both sca led to the analog programm ing level that is s et in the VAP mode.

Name

programming modes are used for the respective voltage and current control. If local (front pan el) cont rol is used or n on be inaccurate and should not be used for monitoring. Conversely, if isolated

Auxiliary Outputs

The auxiliary outputs are an add itional isolated source. The auxiliary output ha s two output s: +5 V output on J3.9 and a +15 V output on J3.11. The auxiliary output operates independently of the main output. It is enabled or disabled from the front panel by pressing the OUTPUT ENABLE Aux button. When the Aux output is enabled, the OUTPUT ENABLE Aux button is illuminated. Like the main output of the power supply, the A ux also has the ability to Autostart at power up. See “Output Auto Start Mode (Auto Restart)” on page 42 and “Auxiliary Auto Start Mode” on page 43 for details on controlling this feature.

The table that follows provides a summary of the options available for programming output voltage and current set point using an analog source.

1. The resolution c an be adjusted in inc rements of 0.1 volts.

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Reference

Function

J1.1

+SNS Positive (+)

Sense

J1.2

+LS Positive (+)

Local Sense

J1.3

-NC J1.4

-NC

J1.5

-LS Negative (-)

Local Sense

J1.6

-SNS Negative (-)

Sense

J1.7

COM Analog Common

Same as power supply negative sense (-SNS)

J1.8

COM Analog Common

Same as power supply negative sense (-SNS)

J1.9

VOL_PR

Analog Voltage Programming Input

J1.10

CUR_PR

Analog Curre nt P ro gr a mmin g I np ut

J1.11

VOL_RES_PR

Voltage Re s i s tive Programming Input

J1.12

CUR_RES_PR

Current Resistive Programming Input

J1.13

VOL_MON

Voltage Monitor. The scale of this output is set by the APG voltage

J1.14

CUR_MON

Current Monitor. The scale of this output is set by the APG current

Jumper. Factory default condition.

Analog Programming (APG) Connector J 1

The APG connector is an 18-pin connector. See Figure 19. The APG connector provides access to the following functions:

• Sense control

• Analog programming and monitoring.

Figure 19: APG Connector Terminals

(Pins 1 and 2 are jumpered; Pins 5 and 6 are jumpered).

input range selected (see Important note at foot of this table).

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Reference

Function

J1.15

EXT_CC_CV

External CC/CV. Indicates the state of the operate mode. When in

J1.16

CSH

Current Share. Used to hook up units for current shari ng. Output

J1.17

REF_I

Current Re ference Input. Slave input from current share output on

J1.18

CV mode, logic high is output and when in CC mode, logi c low is output. Logic is TTL/CMOS compatible.

from master unit. Slave units should be le ft open.

the master unit.

Important: Non-isolated monito r lines are only valid in local control, digital remote and non-isolated analog

programming modes for the respective voltage and current control. If isolated analog programming is used, the isolated monitor lines should be used as the non-isolated monitoring lines will not accurately reflect the output state of the power supply.

Making Control Connections

CAUTION: Equipment damage

Before making connections from external cir cuits to the Anal og Programming Connector, turn the front panel power switch to Off and wait until the front panel displays are not illuminated.

CAUTION: Equipment damage

Program/monitor signal and return are internally connected to the power supply negative output (-S). Do not attempt to bias these a wa y from that potential.

To connect the output wires to the APG and DC output connector:

1. Insert a 3/32 inch slot-head screwdriver into the orange-colored box of the connector until the end of the spring is reached.

2. Hold the connector open and insert the applicable output wire.

3. Remove the screwdriver.

Figure 20: Inserting Screwdriver into Spring Terminal Block

Figure 21: APG and DC Output Connector

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ith a

Use load wires that match the maximum voltag e,

Type TE W

105 °C and 600 V is su itabl e for use with all t he Seri es 2268

Wiring

WARNING: Shock hazard

There is a potential shock hazard at the output when using a power supply w rated output greater than 60 V. current, and temperature ranges that you expect in your application. wire with ratings of power supplies.

For most connectors and jump ers, use any suitab le wire such a s 20 to 26 AWG stranded wire. For lowest noise performance, use shielded twisted pair wiring of 20 to 26 AWG of the shortest length possible. Ground the shield to pin J1.7 (analog common) on the Analog Programming Connector or to the chassis via one of the Analog Programming Connector screws.

ANALOG PROGRAMMING MODE

For more details about connections for your particular m odel, see “Rear Panel ” on page

15.

CAUTION: Equipment damage

The program/monitor signal and return are internally connected to the power supply's negative output. Do not attempt to bias these away from that potential. See “Making Control Connections” on page 75.

Analog Programming With External Volt a ge S ourc e

Figure 22: Programming Output Voltage using an Ex ter n al Voltage Source

Figure 23: Programming Output Current using an Exter n al Voltage Source

76 2268S-901-01 Rev. A / January 2015

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Voltage-Controlled Vol t a ge APG Setup

Activating APG Voltage Mode

To activate APG voltage mode using an external voltage source:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select (voltage source from non-isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Once the desired level has been selected, press the rotary Adjust/Enter control to commit the change.

The display will return to the normal display.

Deactivating APG Voltage Mode

To deactivate the APG voltage mode:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Ente r control to commit the change. The display will return to the normal display.

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Quick Ti p: Remote

page 101.

The SCPI commands for these instructions are:

|AVOLtage|IAVoltage|ARESistive|IAResistive>

Query for Analog Voltage Input Level

To query for analog voltage input level from non-isolated input:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

is displayed on the output voltage display.

2. If the m ode is cur rently then select any other APG mode. I f this step is done, be sure to restore the APG setting to when the operation is complete. Otherwise, do not rotate the rotary Adjust/Enter control to keep the current APG mode.

3. Press the rotary Adjust/Enter control to select the APG mode. The output voltage display should r ead and the output current display will display

APG level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the APG mode was modified in step 2, execute the procedure to deactivate the APG voltage mode.

Operation uses these SCPI commands. See

[:]SYSTem[<channel>]:REMote:SOURce[:VOLTage] <?|LOCal

[:]SYSTem[<channel>]:COMMunicate:APRogram:LEVel[:VOLTage] [:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram[:VOLTage][:DC]?

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Voltage-Controlled Current APG Setup

Activating APG Current Mode

To activate APG current mode using an external voltage source:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the mode control is already at the CAP position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select source (Voltage source from non-isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select the input source level using the rotary Adjust/Enter control.

5. Once the desired level has been selected, press the rotary Adjust/ Enter control to commit the change.

The display will return to the normal display.

Deactivating APG Current Mode

To deactivate the APG current mode:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the mode control is already at the CAP position.

2. ΧΑΠρ is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Enter control to commit the change. The display will return to the normal display.

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Quick Ti p: Remote

page 101.

The SCPI commands for these instructions are:

|AVOLtage|IAVoltage|ARESistive|IAResistive>

Query for Analog Current Input Level

To query for analog current input level from non-isolated input:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the mode control is already at the CAP position.

is displayed on the output voltage display.

3. Press the rotary Adjust/Enter control to select the APG mode. The output voltage display should r ead and the ou tpu t cu rrent d isp lay w ill d isp lay

APG level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the APG mode was modified in step 2, execute the procedure to deactivate the APG voltage mode.

Operation uses these SCPI commands. See

[:]SYSTem[<channel>]:REMote:SOURce[:VOLTage] <?|LOCal

[:]SYSTem[<channel>]:COMMunicate:APRogram: LEVel:CURRent [:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram:CURRent[:DC]?

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ANALOG PROGRAMMING WITH EXTERNAL RESISTOR

Figure 24: Programming Output Voltage using an External Resistor

Figure 25: Programming Output Current using an External Resistor

APG Connector

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Resistive-Controlled Voltage APG Setup

Activating APG Voltage Mode

To activate APG voltage mode using an external resistor:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select (resistor source from non-isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select the input source level using the rotary Adjust/Enter control.

5. Once the desired level has been selected, press the rotary Adjust/Enter control to commit the change.

The display will return to the normal display.

Deactivating APG Voltage Mode

To deactivate the APG voltage mode:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Ente r control to commit the change. The disp lay will return to the normal display.

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Quick Ti p: Remote

The SCPI commands for these instructions are:

Query for Analog Voltage Input Level

To query for analog voltage input level from non-isolated input:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Ente r con tro l if th e mode control is already at the VAP position.

is displayed on the output voltage display.

3. Press the rotary Adjust/Enter control to select the APG mode. The output voltage display should r ead and the output current display will display

APG level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the APG mode was modified in step 2, execute the procedure to deactivate the APG voltage mode.

operation uses these SCPI commands. See page 101.

[:]SYSTem[<channel>]:COMMunicate:APRogram:LEVel[:VOLTage] [ :ISOlated] [:]MEASure[<channel>][:SCALar]:APRogram[:VOLTage][:DC]?

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Resistive-Controlled Current APG Setup

Activating APG Current Mode

To activate APG current mode using an external resistor source:

1. Turn the 9-position mode control to the CAP position to press the rotary Adjust/Enter control if the control knob is already at CAP position.

is displayed on the output voltage display.

2. Turn rotary Adjust/Enter control to select (voltage source from non-isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Once the desired level has been selected, press the rotary Adjust/Enter control to commit the change.

The display will return to the normal display.

Deactivating APG Current Mode

To deactivate the APG current mode:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the mode control is already at the CAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Ente r control to commit the change. The display will return to the normal display.

84 2268S-901-01 Rev. A / January 2015

Series 2268 850 Watt DC Power Supplies Reference Manual Analog Programming & Isolated Analog Programming

Quick Ti p: Remote

The SCPI commands for these instructions are:

Query for Analog Current Input Level

To query for analog current input level from non-isolated input:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Ente r con tro l if th e mode control is already at the CAP position.

is displayed on the output voltage display.

3. Press the rotary Adjust/Enter control to select the APG mode. The output voltage display should r ead and the ou tpu t cu rrent d isp lay w ill d isp lay

APG level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the APG mode was modified in step 2, execute the procedure to deactivate the APG voltage mode.

Operation uses these SCPI commands. See page 101.

[:]SYSTem[<channel>]:COMMunicate:APRogram: LEVel:CURRent [:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram:CURRent[:DC]?

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VOLTAGE AND CURRENT READBACK

Figure 26: Voltage Readback using APG Connector J1

Figure 27: Current Readback using APG Connector J1

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Function

850 W

Auxiliary +5 V and +15 V outputs

standard

OUTPUT ENABLE Aux

standard

Power On Status (output)

standard

SD—Shutdown (input)

standard

Interlock

standard

ISOL programming and monitoring

standard

IS_VOL_PR_V

IS_VOL_PR_C

IS_MON_VOL

AUX1 (+5V)

S_MON_CUR

INTER_LOCK_1

INTER_LOCK_2

MAIN_PS_GOO

SD (Shutdown Main O/P)

AUX2 (+15V)

ISO_VOL_RES

COM_ISOLATE

ISO_CUR_RES_P

AUX1 _&_AUX2

COM_ISOLATE

ISOLATED ANALOG PROGRAMMING MODE (ISOL)

See “Rear Panel Familiarization” on page 15 for more details about connections.

AUX Output and Isolated Analog Progr am m ing (ISOL) Connector

The AUX Output and Isolated Analog Programming (ISOL) Connector is a 15-pin female DSUB connector. See Figure 28. All pins on this connector are electrically isolated from the output of the power supply.

The AUX Output and ISOL Connector provide access to the following functions:

Figure 28: AUX Output and ISOL Connector Pinout

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Reference

Function

J3.1

AUX_ON_OFF

Auxiliary enable/disable

J3.2

COM_ISOLATED

Isolated Common (Isolated from Main Output and Communication. Return wire for

J3.3

IS_VOL_PR_VOL

Isolated Analog Voltage Pro gr amming Input

J3.4

IS_VOL_PR_CUR

Isolated Analog Current Programming Input

J3.5

IS_MON_VOL

Isolated Voltage Monitor. Scaled to the value of the Voltage Analog Programming

J3.6

COM_ISOLATED

Isolated Common (Isolated from Main Output and Communication. Ret urn wir e for

J3.7

ISO_CUR_RES_PR

Isolated Current Resistive Programming

J3.8

ISO_VOL_RES_PR

Isolated Voltage Resistive Programming

J3.9

+AUX 1

+5 V Isolated Output

J3.10

IS_MON_CUR

Isolated Current Monitor. Sc aled to the value of t he Voltage Analog Programming

J3.11

+AUX 2

+15 V Isolated Output

J3.12

Shutdown. Input to power supp ly to disab le output. This input has user selectable

J3.13

PS_GOOD

PS_GOOD. Power supply output enabled.

J3.14

INTER_LOCK 1

Interlock. Dry contact type. Shorting pins J3.14 and J3.15 while the interlock

J3.15

INTER_LOCK 2

Interlock

+5 V, +15 V Auxiliary Voltage.

Level.

control signals, monitoring and programming.

Level.

negative logic operation via front panel or remote digital input/output.

functionality is enabled, will enable the o utput of the power supply.

1. Important: Isolated monitor lines are only valid when Isolated analog programming modes are used for the respective voltage and current control. If local control, digital control or non-isolated APG is used, the non-isolated monitor lines should be used as the isolated monitor lines will not accurately reflect the output state of the power supply.

2. Use unshielded cable u p to 9.84 fe et (3 m) l ength wit h high-density D-Sub type connector and a ferrite bead (Fair-Rite part number 0443164251).

CAUTION: Equipment damage

Do not drive or apply a voltage to pins J3.14 (Inter_Lock 1) or to pins J3.15 (Inter_Lock 2).

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Making ISOL Control Connec t ions

CAUTION: Equipment damage

Before making connections from external circuits to the Isolated Analog Programming Connector, turn the front panel power switch to off and wait until the front panel displays have gone out.

For most connectors and jumpers, use any suitable wire such as 22 AWG stranded wire. For lowest noise performance, use shielded twisted pair wiring of 22 AWG. Use the shortest leads possible. +5 V and +15 V Auxiliary Output reference to pin 2 and 6 (isolated common) on the ISOL Connector.

ISOL Programming With Exte rnal Voltage Source

Figure 29: Programming Output Voltage using an Isolated External Voltage Source

ISOL Connector

Figure 30: Programming Output Current using an Isolated External Voltage Source

ISOL Connector

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Voltage-Controlled Vol t a ge IS O L Setup

Activating ISOL Programming Voltage Mode

To activate ISOL programming voltage mode with an external voltage source:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

is displayed on the output voltage display.

2. Turn rotary Adjust/Enter control to select (voltage source from isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select th e in pu t source level using the rotary Adjust/Enter control.

5. Once the desired level has been selected, press the rotary Adjust/ Enter control to commit the change.

The display will return to the normal display.

Deactivating ISOL Voltage Mode

To deactivate the ISOL voltage mode:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the mode control is already at the VAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Ente r control to commit the change. The display will return to the normal display.

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Quick Ti p: Remote

The SCPI command for these instructions are:

|LOCal

Query for ISOL Voltage Input Level

To query for ISOL voltage input level from non-isolated input:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the control knob is already at the VAP position.

is displayed on the output voltage display.

2. If the mo de is currently then select any other ISOL mode. If this step is done, be sure to restore the ISOL setting to when the operation is complete. Otherwise, do not rotate the rotary Adjust/Enter control to keep the current ISOL mode.

3. Press the rotary Adjust/Enter control to select the ISOL mode. The output voltage display should r ead and the output current display will display

ISOL level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the ISOL mode was modified in step 2, execute the procedure to deactivate the ISOL voltage mode.

Operation uses these SCPI commands. See page 101.

[:]SYSTem[<channel>]:REMote:SOURce[:VOLTage] <? |AVOLtage|IAVoltage|ARESistive|IAResistive>

[:]SYSTem[<channel>]:COMMunicate:APRogram:LEVel [:VOLTage][:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram[:VOLTage] :ISOlated[:DC]?

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Voltage-Controlled Current ISOL Setup

Activating ISOL Programming Current Mode

1. Turn the 9-position mode control to the CAP position or press the rotary adjust/Enter control if the control knob is already at the CAP position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select (voltage source from isolated connector).

3. Press the rotary adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select the input source level using the rotary adjust/Enter control.

5. Once the desired level has been selected, press the rotary adjust/ Enter control to commit the change.

The display will return to the normal display.

Deactivating ISOL Current Mode

To deactivate the ISOL current mode:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the control knob is already at the VAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/Ente r control to commit the change. The display will return to the normal display.

92 2268S-901-01 Rev. A / January 2015

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Quick Ti p: Remote

The SCPI command for these instructions are:

Query for ISOL Current Input Level

To query for ISOL current input level from non-isolated input:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the control knob is already at the CAP position.

is displayed on the output voltage display.

3. Press the rotary adjust/Enter control to select the ISOL mode. The output voltage display should r ead and the ou tpu t cu rrent d isp lay w ill d isp lay

ISOL level.

4. Press the rotary adjust/Enter control to return to normal mode.

5. If the ISOL mode was modified in step 2, execute the procedure to deactivate the ISOL voltage mode.

operation uses these SCPI commands. See page 101.

[:]SYSTem[<channel>]:COMMunicate:APRogram:LE Ve l:CURRent [:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram:CURRent

:ISOlated[:DC]?

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ANALOG PROGRAMMING WITH EXTERNAL RESISTOR

Figure 31: Programming Output Voltage using an Isolated External Resistor

ISOL Connector

Figure 32: Programming Output Current using an Isolated External Resistor

ISOL Connector

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Resistive-Controlled Voltage ISOL Setup

Activating ISOL Programming Voltage Mode

To activate ISOL programming voltage mode using an external resistor:

1. Turn the 9-position mode control to the VAP position or press the rotary adjust/Enter control if the control knob is already at the VAP position.

is displayed on the output voltage display.

2. Turn the rotary Adjust/Enter control to select (resistor source from isolated connector).

3. Press the rotary adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select the input source level using the rotary adjust/Enter control.

5. Once the desired level has been selected, press the rotary Adjust/ Enter control to commit the change.

The display will return to the normal display.

Deactivating ISOL Voltage Mode

To deactivate the ISOL voltage mode:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the control knob is already at the VAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary adjust/Enter control to commit the change. The display will return to t h e normal display.

2268S-901-01 Rev. A / January 2015 95

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Quick Ti p: Remote

The SCPI command for these instructions are:

|LOCal

Query for ISOL Voltage Input Level

To query for ISOL voltage input level from non-isolated input:

1. Turn the 9-position mode control to the VAP position or press the rotary Adjust/Enter control if the control knob is already at the VAP position.

is displayed on the output voltage display.

3. Press the rotary adjust/Enter control to select the ISOL mode. The output voltage display should r ead and the output current display will display

ISOL level.

4. Press the rotary adjust/Enter control to return to normal mode.

5. If the ISOL mode was modified in step 2, execute the procedure to deactivate the ISOL voltage mode.

Operation uses these SCPI commands. See page 101.

[:]SYSTem[<channel>]:REMote:SOURce[:VOLTage] <? |AVOLtage|IAVoltage|ARESistive|IAResistive>

[:]SYSTem[<channel>]:COMMunicate:APRogram:LEVel [:VOLTage][:ISOLated] [:]MEASure[<channel>][:SCALar]:APRogram[:VOLTage]

:ISOlated[:DC]?

96 2268S-901-01 Rev. A / January 2015

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Resistive-Controlled Current ISOL Setup

Activating ISOL Resistive-Controlled Current Setup

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the control knob is already at the CAP position.

is displayed on the output voltage display.

2. Turn rotary Adjust/Enter control to select (voltage source from isolated connector).

3. Press the rotary Adjust/Enter control to commit the selected mode. is displayed on the output voltage display.

4. Select the input sourc e leve l using the rotary Ad just/Enter control.

5. Once the desired level has been selected, press the rotary Adjust/ Enter control to commit the change.

The display will return to the normal display.

Deactivating ISOL Current Mode

To deactivate the ISOL current mode:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the control knob is already at the CAP position.

2. is displayed on the output voltage display.

3. Turn the rotary Adjust/Enter control to select .

4. Press the rotary Adjust/E nter con trol to co mm it the chang e. The di splay w ill return to the normal display.

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Quick Ti p: Remote

The SCPI command for these instructions are:

Query for ISOL Current Input Level

To query for ISOL current input level from non-isolated input:

1. Turn the 9-position mode control to the CAP position or press the rotary Adjust/Enter control if the control knob is already at the CAP position.

is displayed on the output voltage display.

3. Press the rotary Adjust/Enter control to select the ISOL mode. The output voltage display should r ead and the output current display will d ispla y

ISOL level.

4. Press the rotary Adjust/Enter control to return to normal mode.

5. If the ISOL mode was modified in step 2, execute the procedure to deactivate the ISOL voltage mode.

operation uses these SCPI commands. See page 101.

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98 2268S-901-01 Rev. A / January 2015

Tektronix 2268 DC Power Supply User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

WELCOME

Introduction

EXTENDED WARRANTY

CONTACT INFORMATION

FEATURES AND OPTIONS

UNPACKING AND INSPECTING

Inspect for Damage

Shipment Contents

SERIES 2268 850-WATT MODELS

RACK MOUNT KIT OPTIONS

FRONT PANEL FAMILIARIZATION

REAR PANEL FAMILIARIZATION

BASIC SETUP PROCEDURE

Installation

STEP 1: INSPECTING AND CLEANING

Initial Inspection

Periodic Cleaning

STEP 2: LOCATION AND MOUNTING

Rack Mounting

Ventilation

STEP 3: CONNECTING AC INPUT POWER

AC Input Connector

STEP 4: SELECTING LOAD WIRES

Load Wiring

Insulation Rating

Current Carrying Capaci ty

Maximum Load Wiring Length For Operation With Sense Lines

Noise and Impedance Effects

STEP 5: PERFORMING FUNCTIONAL TESTS

Powering the Power Supply On/Off

Voltage and Current Mode Oper a ti on Check s

STEP 6: CONNECTING LOADS

DC Output Connectors

20 V-40 V Models

60 V-150 V Models

Inductive Loads and Batterie s

Connecting Single Loads

Connecting Multiple Loads

STEP 7: CONNECTING REMOTE SENSING

INTRODUCTION

Local Operatio n

CONFIGURING SETTINGS FROM THE FRONT PANEL

Using the Rotary Adjust/Enter Control

Coarse and Fine Adjustment Modes

NAVIGATING THE MENU SYSTEM

Setting VOLTS and AMPS Modes

Normal Display Mode and Inac ti vi ty Timeout

DISPLAY MESSAGES ON THE FRONT PANEL

STANDARD (LOCAL) OPERATION

OPERATING MODES

Constant Voltage (CV) Mode Operat ion

Constant Current (CC) Mode Operation

Constant Power (CP) Mode Operation

Automatic Mode Crossover

SHIPPED CONFIGURATION (LOCAL OPERATION)

ENABLING THE OUTPUT

ENABLING THE AUXILIARY OUTPUT

OUTPUT AUTO START MODE (AUTO RESTART)

AUXILIARY AUTO START MODE

CONSTANT POWER MODE

ALARMS AND ERRORS

CLEARING ALARMS

Clearing Triggered and Manual Alarms

Clearing a Flash Failure Alarm

Clearing Automatic Alarms

Front Panel Alarm LED

Alarm Masking

Alarm Output Latching

SETTING FOLDBACK MODE

RESETTING ACTIVATED FOLDBACK PROTECTION

USING OVER VOLTAGE PROTECTION (OVP)

Defining the OVP Set Point

USING UNDER VOLTAGE PROTECTION (UVP)

Defining the UVP Set Point

OVER CURRENT PROTECTION (OCP)

USING OVER TEMPERATURE PROTECTION LOCK (OTP)