Keithley Keithley Instruments 2303 Manual

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Model 2303/2303B/2303-PJ

High Speed Power Supply User’s Manual

A GREATER MEASURE OF CONFIDENCE

5/03

Model 2303/2303B/2303-PJ High Speed Power Supply

User’s Manual

Manual Print History

The print history shown below lists the printing dates of all Revisions and Addenda created for this manual. The Revision Level letter increases alphabetically as the manual undergoes subsequent updates. Addenda, which are released between Revisions, contain important change information that the user should incorporate immediately into the manual. Addenda are numbered sequentially. When a new Revision is created, all Addenda associated with the previous Revision of the manual are incorporated into the new Revision of the manual. Each new Revision includes a revised copy of this print history page.

A (Document Number 2303-900-01) ............................................................January 1998

Revision

Revision B (Document Number 2303-900-01) .......................................................... February 1998

Revision C (Document Number 2303-900-01) .............................................................August 1998

Revision D (Document Number 2303-900-01)........................................................November 1999

Addendum D (Document Number 2303-900-02) ........................................................October 2000

Revision E (Document Number 2303-900-01) ............................................................October 2000

Revision F (Document Number 2303-900-01).............................................................. August 2003

All Keithley product names are trademarks or registered trademarks of Keithley Instruments, Inc. Other brand names are trademarks or registered trademarks of their respective holders.

afety Precautions

The following safety precautions should be observ some instruments and accessories would normally be used with non-hazardous 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 manual for complete product speciﬁcations.

If the product is used in a manner not speciﬁed, the protection provided by the product 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 manual. 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, and perform safe installations and repairs of products. Only properly trained service personnel may perform installation and service procedures.

Keithley products are designed for use with electrical signals that are rated Measurement Category I and Measurement Category II, as described in the International Electrotechnical Commission (IEC) Standard IEC 60664. Most measurement, control, and data I/O signals are Measurement Category I and must not be directly connected to mains voltage or to voltage sources with high transient over-voltages. Measurement Category II connections require protection for high transient over-voltages often associated with local AC mains connections. Assume all measurement, control, and data I/O connections are for connection to Category I sources unless otherwise marked or described in the Manual.

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 30V RMS,

42.4V peak, or 60VDC 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 volts, 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, make sure 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 ca-

ed before using this product and any associated instrumentation. Although

5/03

bles or jumpers, installing or removing switching cards, or making internal changes, such as installing or remo

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.

The instrument and accessories must be used in accordance with its speciﬁcations and operating instructions or the safety of 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 same type and rating for continued protection against ﬁre hazard.

Chassis connections must only be used as shield connections for measuring circuits, NOT as safety earth ground connections.

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

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

The symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.

The symbol on an instrument shows that it can source or measure 1000 volts or more, including the combined effect of normal and common mode voltages. Use standard safety precautions to avoid personal contact with these voltages.

The symbol indicates a connection terminal to the equipment frame.

The WARNING heading in a manual 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 a manual 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.

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., 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.

ving jumpers.

Getting Started

General information ..........................................................................

Warranty information....................................................................... 1-2

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

Safety symbols and terms .............................................................. 1-2

Speciﬁcations ................................................................................. 1-2

Inspection ....................................................................................... 1-3

Options and accessories ................................................................. 1-3

Power supply overview ..................................................................... 1-4

Remote display option ....................................................................... 1-6

Power-up ............................................................................................ 1-6

Line power connection .................................................................. 1-6

Fuse replacement ........................................................................... 1-7

Power-up sequence ........................................................................ 1-7

Display modes ................................................................................... 1-8

Default settings .................................................................................. 1-9

Setups — Save, Power-on, and Recall ......................................... 1-10

Menu ................................................................................................ 1-11

Rules to navigate MENU ............................................................. 1-13

SCPI programming .......................................................................... 1-13

2 Basic Power Supply Operation

Test connections

Outputting voltage and current .......................................................... 2-3

Setting output voltage and current limit ........................................ 2-3

Operate ........................................................................................... 2-8

SCPI programming — outputting voltage and current .................. 2-8

Reading back V and I ...................................................................... 2-11

Actual V and I display mode ........................................................ 2-11

Measurement conﬁguration .......................................................... 2-11

SCPI programming — measure V and I, and DVM input ........... 2-12

Independent voltage measurements (DVM) .................................... 2-13

DVM input display mode ............................................................. 2-13

Measurement conﬁguration .......................................................... 2-13

SCPI programming — DVM........................................................ 2-13

Sink operation ................................................................................. 2-14

Programming examples.................................................................... 2-15

Outputting and reading back V and I............................................ 2-15

DVM measurements ..................................................................... 2-15

1-2

................................................................................ 2-2

3 Pulse Current Measurements

Overvie

Average readings count ..................................................................... 3-3

Measurement conﬁguration ............................................................... 3-4

SCPI programming ............................................................................. 3-7

w ............................................................................................ 3-2

Trigger level ................................................................................... 3-3

Trigger delay .................................................................................. 3-3

Integration times ............................................................................ 3-3

Current range .................................................................................. 3-4

Integration times ............................................................................ 3-4

Average readings count .................................................................. 3-5

Trigger delay and trigger level ........................................................ 3-5

Pulse current display mode ............................................................. 3-5

Pulse current measurement procedure ............................................ 3-6

Determining correct trigger level (pulse current) ........................... 3-6

Pulse current digitization ................................................................ 3-9

Programming examples ................................................................ 3-10

4 Long Integration Measurements

Overvie

Measurement conﬁguration ............................................................... 4-5

Long integration measurement procedure ........................................ 4-7

SCPI programming ............................................................................ 4-9

w ............................................................................................ 4-2

Integration time .............................................................................. 4-3

Trigger edge .................................................................................... 4-3

Trigger level ................................................................................... 4-3

Pulse timeout .................................................................................. 4-4

Current range .................................................................................. 4-5

Integration time ............................................................................... 4-5

Pulse timeout .................................................................................. 4-6

Trigger edge and trigger level ........................................................ 4-6

Long integration display mode ....................................................... 4-7

General notes .................................................................................. 4-8

Determining correct trigger level (long integration)....................... 4-8

Programming example .................................................................. 4-11

5 Relay Control

Overview ........................................................................................... 5-2

Connections ....................................................................................... 5-4

Controlling the relay .......................................................................... 5-5

SCPI programming ........................................................................ 5-5

6 GPIB Operation

Introduction ....................................................................................... 6-2

GPIB bus connections ....................................................................... 6-2

Primary address ................................................................................. 6-3

Output format .................................................................................... 6-3

General bus commands ..................................................................... 6-4

REN (remote enable) ..................................................................... 6-4

IFC (interface clear) ....................................................................... 6-4

LLO (local lockout) ....................................................................... 6-5

GTL (go to local) ........................................................................... 6-5

DCL (device clear) ........................................................................ 6-5

SDC (selective device clear) .......................................................... 6-5

GET (group executive trigger) ....................................................... 6-5

SPE, SPD (serial polling) .............................................................. 6-5

Front panel aspects of GPIB operation ............................................. 6-6

Remote indicator and LOCAL key ................................................ 6-6

Error and status messages .............................................................. 6-6

Programming syntax ......................................................................... 6-7

Command words ............................................................................ 6-7

Program messages ....................................................................... 6-10

Response messages ...................................................................... 6-12

Message exchange protocol ......................................................... 6-12

7 Status Structure

Overview ........................................................................................... 7-2

Status byte and SRQ ...................................................................... 7-2

Status register sets .......................................................................... 7-2

Queues ........................................................................................... 7-2

Clearing registers and queues ............................................................ 7-4

Programming and reading registers ................................................... 7-5

Programming enable registers ....................................................... 7-5

Reading registers ........................................................................... 7-5

Status byte and service request (SRQ) .............................................. 7-6

Status byte register ......................................................................... 7-7

Service request enable register ...................................................... 7-7

Serial polling and SRQ .................................................................. 7-8

Status byte and service request commands .................................... 7-9

Status register sets

Condition registers ....................................................................... 7-15

Event registers .............................................................................. 7-15

Event enable registers .................................................................. 7-16

Programming example — program and read

measurement event register .................................................... 7-17

Queues ............................................................................................. 7-17

Output queue ................................................................................ 7-17

Error queue ................................................................................... 7-18

............................................................................ 7-10

8 Common Commands

Overvie

w ............................................................................................ 8-2

*IDN? — identiﬁcation query ........................................................ 8-3

*OPC — operation complete ......................................................... 8-3

*OPC? — operation complete query ............................................. 8-3

*SAV <NRf> — save ..................................................................... 8-4

*RCL <NRf> — recall ................................................................... 8-4

*RST — reset ................................................................................. 8-4

*TRG — trigger ............................................................................. 8-4

*TST? — self-test query ................................................................ 8-5

*WAI — wait-to-continue .............................................................. 8-5

9 Signal Oriented Measurement Commands

Overvie

w ............................................................................................ 9-2

:FETCh? ......................................................................................... 9-2

:FETCh:ARRay? ............................................................................ 9-2

:READ? .......................................................................................... 9-3

:READ:ARRay? ............................................................................. 9-3

:MEASure[:<function>]? ............................................................... 9-4

:MEASure:ARRay[:<function>]? .................................................. 9-4

10 DISPlay, FORMat, and SYSTem

DISPlay subsystem .......................................................................... 10-2

:DISPlay:ENABle ................................................................ 10-2

:DISPlay:TEXT:DATA <a> ......................................................... 10-2

:DISPlay:TEXT:STATe ........................................................ 10-3

FORMat subsystem ......................................................................... 10-4

FORMat[:DATA] <type> ............................................................. 10-4

FORMat:BORDer <name> .......................................................... 10-6

:SYSTem subsystem ........................................................................ 10-7

:SYSTem:POSetup <name> ........................................................ 10-7

11 SCPI Tables

SCPI command subsystems reference tables .................................. 11-2

A Speciﬁcations

B Error and Status Messages

C Emulation Commands

HP 6632A power supply emulation commands ............................... C-2

Fluke PM2811 power supply emulation commands ........................ C-5

D Emulation Commands

Selecting the 488.1 protocol.............................................................. D-2

Protocol differences............................................................................ D-3

List of Illustrations

Getting Started

High speed power supply

Simpliﬁed power supply diagram ...................................................... 1-5

2 Basic Power Supply Operation

Typical connections

Output capabilities ............................................................................. 2-3

Sink operation example.................................................................... 2-12

3 Pulse Current Measurements

Pulse current measurement ................................................................

5 Relay Control

Relay control .....................................................................................

Miniature phono plug ........................................................................ 5-4

6 GPIB Operation

IEEE-488 connector ..........................................................................

7 Status Structure

Status model structure .......................................................................

16-bit status register .......................................................................... 7-5

Status byte and service request .......................................................... 7-6

Standard event status ....................................................................... 7-11

Operation event status ..................................................................... 7-12

Measurement event status ................................................................ 7-13

Questionable event status ................................................................ 7-14

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

........................................................................... 2-2

3-2

5-3

6-2

7-3

10 DISPlay

IEEE-754 single precision data format ...........................................

IEEE-754 double precision data format .......................................... 10-6

, FORMat, and SYSTem

10-5

List of Tables

1 Getting Started

Factory defaults (RST) ...................................................................... 1-9

MENU structure .............................................................................. 1-12

2 Basic Power Supply Operation

Current ranges.................................................................................... 2-4

SCPI commands — outputting voltage and current ........................ 2-7

SCPI commands — measure V and I, and DVM input ................... 2-10

Sink current limits ............................................................................ 2-12

3 Pulse Current Measurements

SCPI commands — pulse current measurements ............................. 3-7

4 Long Integration Measurements

SCPI commands — long integration measurements ........................ 4-9

5 Relay Control

Switchcraft connection accessories ................................................... 5-4

SCPI command — output relay control ............................................ 5-5

6 GPIB Operation

General bus commands ..................................................................... 6-4

7 Status Structure

Common and SCPI commands — reset registers and clear queues .. 7-4

Command commands — status byte and service request

enable registers .................................................................... 7-9

Common and SCPI commands — condition registers ................... 7-15

Common and SCPI commands — event registers .......................... 7-15

Common and SCPI commands — event enable registers ............... 7-16

SCPI commands — error queue ..................................................... 7-19

8 Common Commands

IEEE-488.2 common commands and queries.................................... 8-2

*OPC and *OPC? commands ........................................................... 8-4

9 Signal Oriented Measurement Commands

Signal oriented measurement command summary ........................... 9-2

10 DISPlay, FORMat, and SYSTem

SCPI commands — display ............................................................. 10-2

SCPI commands — data format....................................................... 10-4

SCPI commands — system ............................................................. 10-7

11 SCPI Tables

DISPlay command summary ........................................................... 11-3

FORMat command summary .......................................................... 11-3

OUTPut command summary ........................................................... 11-3

SENSe command summary ............................................................. 11-4

SOURce command summary .......................................................... 11-6

STATus command summary ............................................................ 11-7

SYSTem command summary .......................................................... 11-8

C Emulation Commands

HP commands used to control the power supply .............................. C-2

Fluke commands used to control Model 2303/2303B/2303-PJ ....... C-5

Getting Started

• General information — Covers general information that includes warranty informa-

tion, contact information, safety symbols and terms, inspection and available options and accessories.

• Power supply overview — Summarizes the capabilities of the power supply.

• Remote display option — Explains how to use the optional Model 2304-DISP Display

Module.

• Power-up — Covers line power connection, fuse replacement, and the power up

sequence.

• Display modes — Explains the four display modes of the power supply.

• Default settings — Lists the factory default settings, and explains how to save and recall

settings.

• Menu — Provides a table that summarizes the menu items and includes rules to navigate

the menu structure.

• SCPI programming — Explains how SCPI commands are presented in this manual.

1-2 Getting Started

General information

Warranty information

Warranty information is located at the front of this manual. Should your power supply require warranty service, contact the Keithley representative or authorized repair facility in your area for further information. When returning the instrument for repair, be sure to ﬁll out and include the service form at the back of this manual to provide the repair facility with the necessary information.

Contact information

If you have any questions after reviewing this information, please contact your local Keithley representative or call one of our Applications Engineers at 1-800-3735 (U.S. and Canada only). Worldwide phone numbers are listed at the front of this manual.

Safety symbols and terms

Keithley uses a standard set of safety symbols and terms that may be found on an instrument or in its manual.

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

The symbol on an instrument indicates that the user should refer to the operating instructions located in the manual.

The symbol indicates a connection terminal to the equipment frame.

The

WARNING

injury or death. Always read the associated information very carefully before performing the indicated procedure.

The

CAUTION

ment. Such damage may invalidate the warranty.

Speciﬁcations

Full power supply speciﬁcations can be found in Appendix A of this manual.

heading used in a manual explains dangers that might result in personal

heading used in a manual explains hazards that could damage the instru-

Inspection

The power supply was carefully inspected electrically and mechanically before shipment. After unpacking all items from the shipping carton, check for any obvious signs of physical damage that may have occurred during transit. (Note: There may be a protective ﬁlm over the display lens, which can be removed.) Report any damage to the shipping agent immediately. Save the original packing carton for possible future shipment. The following items are included with every order:

If an additional manual is required, order the appropriate manual package. The manual package includes a manual and any pertinent addenda.

Any improvements or changes concerning the instrument or manual will be explained in an addendum included with the manual. Be sure to note these changes and incorporate them into the manual.

Getting Started 1-3

• Model 2303/2303B/2303-PJ High Speed Power Supply with line cord

• Quick Disconnect Output/DVM Input Connector

• Accessories as ordered

• Certiﬁcate of calibration

• Model 2303/2303B/2303-PJ User’s Manual (P/N 2303-900-00)

• Model 2303/2303B/2303-PJ Service Manual (P/N 2303-902-00)

Options and accessories

The following options and accessories are available for the power supply.

• 2304-DISP remote display unit

• Shielded IEEE-488 cable, 1m (3.3 ft) (P/N 7007-1)

• Shielded IEEE-488 cable, 2m (6.6 ft) (P/N 7007-2)

• Single ﬁxed rack mount kit (P/N 4288-1)

• Dual ﬁxed rack mount kit (P/N 4288-2)

• IEEE-488 Interface/controller for the PCI bus (P/N KPCI-488)

• IEEE-488 interface card for IBM PC/AT (full slot) (P/N KPC-488-2AT)

1-4 Getting Started

WARNING:NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.

CAUTION:FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.

Power supply overview

The power supply (shown in Figure 1-1) can output up to +15V at up to 3A or +9V at up to 5A. Voltage can be set in 1mV steps, and current limit can be set in 100µA steps. Maximum power output is 45W. The power supply can also be used to sink current (up to 2A). As a sink (current polarity is negative), the power supply is dissipating power rather than sourcing it (see “Sink operation” for details).

NOTE Model 2303B has a blank front panel except for a POWER switch and an ON/OFF

LED. Models 2303 and 2303-PJ, and the 2303B if using the Model 2304-DISP remote display module.

Figure 1-1

High speed power supply (Model 2303 shown)

eferences to front panel messages, menus, and keystrokes apply to the

All r

POWER

A) Front Panel

2303 HIGH SPEED POWER SUPPLY 15V/3A 9V/5A

DISPLAY

ISOLATION FROM EARTH:

22 VOLTS MAX.

____

+++

SOURCE SENSE

OUTPUT

15V/3A 9V/5A

IEEE-488

(CHANGE IEEE ADDRESS

WITH FRONT PANEL MENU)

MADE IN

U.S.A.

SOURCE

DVM IN

LOCAL

OPERATE

ENTER

LINE FUSE

SLOWBLOW

2.0A, 250V

LINE RATING

100-120VAC/ 200-240VAC

50, 60 HZ

150VA MAX

SET

RELAY

CONTROL

15VDC MAX

REMOTE DISPLAY

OPTION

B) Rear Panel

Getting Started 1-5

A simpliﬁed diagram of the power supply is shown in Figure 1-2. Note that it can read back

the output voltage (V

) and current (I

meter

). Display resolution for voltage readback is 1mV.

meter

Current Readback Ranges:

• Models 2303 and 2303B – Two ranges for current readback: 5A and 5mA. On the 5A

range, display resolution is 100µA, and on the 5mA range, resolution is 0.1µA.

• Model 2303-PJ –

Two ranges for current readback: 5A and 500mA. On the 5A range,

display resolution is 100µA, and on the 500mA range, resolution is 0.01mA (10µA).

The power supply also has a digital v

oltmeter (DVM) that is independent of the power supply

circuit. The DVM can measure up to +20V (1mV resolution).

When used with a pulsed load, the power supply can read back peak current, idle current, and average current. See Section 3 for details. A long integration (up to 60 seconds) function is provided to measure average current of a low frequency pulse (long period) or a series of pulses. See Section 4 for details.

Figure 1-2

Simplified power supply diagram

Source

I meter

V-Source with I-Limit

V meter

DVM

Digital

Voltmeter

1-6 Getting Started

Remote display option

If the power supply must be mounted in a location where the display is not readily visible or the controls are not easily accessible, the optional Model 2304-DISP Display Module can be used. This display module includes all instrument controls and has a 9 foot cable so the power supply can be operated remotely from a more convenient location.

NOTE When the remote display is attached to a Model 2303B, the power supply acts like a

Model 2303.

The remote display module plugs into the rear panel connector labeled “REMOTE DISPLAY OPTION” (see Figure 1-1B). following message displayed:

REMOTE PANEL

ENABLED

When the remote display module is unplugged, control returns to the main display module.

NOTE When connecting or disconnecting the 2304-DISP remote display, allow a few sec-

onds for the power supply to reco nects of the remote display may cause the power supply to hang or appear to hang. Disconnecting the remote display and waiting a few seconds to reconnect it may clear the problem. If not, cycling power on the power supply clears the condition.

When plugged in, the main display module is disabled with the

gnize the action. Fast, repeated connects/discon-

Power-up

Line power connection

The power supply operates from a line voltage in the range of 100 to 240V at a frequency of 50 or 60Hz. Line voltage and frequency are automatically sensed, therefore there are no switches to set. Check to see that the line power in your area is compatible. Use the :SYSTem :LFRequency? query (Section 10) to read the line frequency.

Perform the following steps to connect the power supply to the line power and turn it on:

1. Before plugging in the power cord, make sure the front panel power switch is in the off (0)

position.

2. Connect the female end of the supplied power cord to the AC receptacle on the rear panel.

Getting Started 1-7

WARNING

3. Turn on the power supply by pressing the front panel power switch to the on (1) position.

Fuse replacement

A rear panel fuse protects the power line input of the power supply. If the line fuse needs to

be replaced, perform the following steps:

1. The fuse is located in a drawer below the AC receptacle (see Figure 1-1B). At the top of the fuse drawer is a small tab. At this location, use a thin-bladed knife or screwdriver to pry the fuse drawer open.

2. Slide the fuse drawer out to gain access to the fuse. Note that the fuse drawer does not pull all the way out of the power module.

3. Snap the fuse out of the drawer and replace it with the same type (250V, 2.0A, 5 time lag). The Keithley part number is FU-81.

CAUTION

The power cord supplied with the power supply contains a separate ground for use with grounded outlets. When proper connections are made, instrument chassis is connected to power line ground through the ground wire in the power cord. Failure to use a grounded outlet may result in personal injury or death due to electric shock.

20mm

For continued protection against ﬁre or instrument damage, only replace the fuse with the type and rating listed. If the instrument repeatedly blows fuses, locate and correct the cause of the problem before replacing the fuse.

4. Push the fuse drawer back into the power module.

Power-up sequence

On power-up, the power supply performs self-tests on its EPROM and RAM.

NOTE

output off (see “Default settings”).

If a problem develops while the instrument is under warranty, return it to Keithley Instruments Inc., for repair.

If the instrument passes the self-tests, the following information is brieﬂy displayed:

Top line

• factory, the address is set to 16.

•

Bottom line

play board. Also displayed is the detected line frequency.

After the power-up sequence, the instrument goes to the presently saved display type with the

— The model number and the IEEE-488 address are displayed. At the

— Firmware revision levels are displayed for the main board and the dis-

1-8 Getting Started

Display modes

For voltage and current readings, there are four display modes described as follows:

• ACTUAL V AND I — This display mode is used to read back the actual output voltage

and current. This display mode is the RST def

• DVM INPUT — This mode is used to display the DC voltage applied to the DVM input

of the power supply

• PULSE CURRENT — This mode is used to display high, lo

measurements. (See Section 3 for details.)

• LONG INTEGRATION — This mode is used to display average current measure-

ments of a pulse or pulses using the long inte

A display mode is selected as follows:

1. Press the DISPLAY key and use the V AND I, DVM INPUT, PULSE CURRENT, or LONG INTEGRATION.

2. With the desired mode displayed, press ENTER. Note that after selecting PULSE CURRENT, use the or pulse average. Examples of the display modes are shown as follows:

ault. (See Section 2 for details.)

. (See Section 2 for details.)

w, or average pulse-current

gration method. (See Section 4 for details.)



or  key to display the desired mode: ACTUAL

or  key to select the desired pulse measurement: pulse high, pulse low,



Actual V and I: 6.116 V ON

1.2058 A

DVM input: DVM INPUT ON

4.993 V

Pulse current: PULSE HI ON

2.1947 A

PULSE LO ON

0.2147 A

PULSE AVG ON

1.1495 A

Long integration: LONG INT ON

1.0236 A

Getting Started 1-9

NOTES

“ON” indicates that the output is turned on. With the output turned off, “OFF” is displayed. See Section 10 for details.

For the Pulse Current and Long Integration display modes, “NO PULSE” is displayed if the output is off or pulses are not detected (output on). See Sections 3 and 4 for details.

When a change is made that affects the readings being taken, dashes are displayed instead of readings. The dashes remain until a valid reading for the new condition is taken.

Any one of the four display modes can be the power-on default. Use the SAVE SETUP item of the MENU to save the selected display mode in memory, and use the POWER ON SETUP item to specify the power-on setup (see “Setups” under “Default settings” for details).

Default settings

The power supply can be set to power-on to the factory default conditions (RST defaults) or

to user-saved setup conditions. The factory default conditions are listed in Table 1-1.

Table 1-1

Factory defaults (RST)

Setting RST default

Output value settings: Voltage (V) 0.000V Current (A) 0.2500A Output state operate Off Display type Actual V and I GPIB address No effect (factory set to 16) GPIB output format No effect (factory set to Keithley

Current range 5 amps (Auto Range off) Integration rate 1.00 PLC Average readings 1 Power on setup No effect (factory set to RST) Current limit mode Lim Output relay No effect (after power cycle, set

Pulse current: High time 33 µsec Low time 33 µsec

and Exponential)

to zero)

1-10 Getting Started

Table 1-1 (cont.)

Factory defaults (RST)

Setting RST default

Average time 33 µsec Average readings 1 Trigger delay 0.00000 sec Trigger level:

Models 2303 and 2303B Model 2303-PJ:

5A range 500mA range

Long integration:

Integration time 1 second Pulse timeout 16 seconds Trigger edge Rising

Trigger level:

Models 2303 and 2303B Model 2303-PJ:

5A range 500mA range

0.000A

0.0000A

0.000A

0.0000A

Setups — Save, Power-on, and Recall

Setups are conﬁgured by SAVE SETUP, POWER ON SETUP and RECALL SETUP items

of the MENU (which is accessed by pressing the MENU key).

NOTE Table 1-2 shows the menu structure. Rules to navigate the menu follow the table.

The setup MENU items are explained as follows:

• SAVE SETUP - Save the present power supply setup to a memory location;

f) or SA

V4.

ed setups; SAV0-SAV4. Note the operate state (output) is always recalled

V5-SAV9 (output on or off). Note that SAV5-SAV9 are not available for the

SAV0-SA

• RECALL SETUP - Return the power supply to the RST defaults (Table 1-1), or to one

of the user sa as OFF.

• POWER-ON SETUP - Select the setup to use at power-up; RST, SAV0-SAV4 (output

of Model 2303-PJ.

When powering up to the SAV0, SAV1, SAV2, SAV3, or SAV4 setup, the output will be off regardless of the operate state when the setup was saved. For example, if the output is on when the setup is saved as SAV0, the power supply will power up with the output off for the SAV0 power-on setup.

Getting Started 1-11

If you want the Model 2303 or 2303B to power up with the output on, you must use SAV5, SAV6, SAV7, SAV8, or SAV9 as the power-on setup. For the SAV5 power-on setup, the power supply will power up to the SAV0 settings, and the output will be on or off depending on the output state when the setup was saved as SAV0. For example, assume the output is on and the setup is saved as SAV0. With SAV0 as the power-on setup, the power supply will power up with the output off. With SAV5 as the power-on setup, the power supply will power up with the output on.

Power-On Setups:

NOTE SAV5 through SAV9 are not available for the Model 2303-PJ.

Models 2303, 2303B and 2303PJ:

V0 (output of SAV1 (output off) SAV2 (output off) SAV3 (output off) SAV4 (output off)

Models 2303 and 2303B:

Model 2303-PJ – 5A, 500mA or AUTO Set integration rate in NPLC (0.01 to 10). Set average reading count (1 to 10). Save present setup in memory (SAV0–SAV4). Recall setup from memory (RST, SAV0–SAV4). Select power-on setup (RST, SAV0–SAV4).* Calibrate Model 2303/2303B/2303-PJ (see Service Manual). Select current limit mode (Limit, Trip, Limit Relay, or Trig Relay). Close (ONE) or open (ZERO) relay control circuit. Display ﬁrmware revision levels. Display serial number of the power supply. Pulse-current conﬁguration:

Set high time integration rate (in µsec.).

Set low time integration rate (in µsec.).

Set average time integration rate (in µsec.).

Set pulse integration rates automatically.

Set average reading count (1 to 100).

Set trigger delay in seconds (0 to 100msec).

Set trigger level:

Models 2303 and 2303B – 0 to 5A.

Model 2303-PJ: 5A range – 0 to 5A

500mA range – 0 to 500mA. Long integration conﬁguration:

Manually set integration time (up to 60 sec).

Automatically set integration time.

Set the “NO PULSE” timeout period (1 to 63 sec).

Select trigger edge (rising, falling or neither).

Set trigger level:

Models 2303 and 2303B – 0 to 5A. Model 2303-PJ: 5A range – 0 to 5A

500mA range – 0 to 500mA.

2. Revision Number displays the ﬁrmware revision level for the microcontroller and the display.

3. Serial Number displays the serial number of the power supply.

Sec 6

Sec 2

Sec 2 Sec 2 Note 1 Note 1 Note 1

Sec 2 Sec 5 Note 2 Note 3 Sec 3

Sec 4

Rules to navigate MENU

• The MENU is accessed by pressing the MENU key.

• Use the

 and  edit keys to display the primary menu items.

• A displayed primary menu item is selected by pressing ENTER. With PULSE CURRENT or LONG INTEGRATION selected, use the ondary items and press ENTER to select the displayed item.

• Settings and selections for a menu item are displayed using the edit keys ( — For a setting, use to increment and decrement the value (unless noted otherwise). — F

or a selection, use

• With the desired setting or selection displayed, press ENTER for it to take effect. Pressing MENU will cancel the edit operation.

• Use the MENU key to back out of the MENU structure.

SCPI programming

SCPI programming information is integrated with front panel operation throughout this manual. SCPI commands are listed in tables, and additional information that pertains exclusively to remote operation is provided after each table. Also, the SCPI tables may reference other sections of this manual.

Getting Started 1-13

 and  edit keys to display the sec-

,, , and ):

 or  to place the cursor on the appropriate digit, and use  and 

 or  to display the desired option (unless noted otherwise).

NOTE Except for Section 11, all SCPI tables in this manual are abridged. That is, they ex-

clude most optional command words and query commands. Optional command words and query commands are summarized as follows.

Optional Command Words — In order to be in conformance with the IEEE-488.2 standard, the power supply accepts optional command words. Any command word that is enclosed in brackets ([]) is optional and does not have to be included in the program message.

Query commands — Most command words have a query form. A query command is identiﬁed by the question mark (?) that follows the command word. A query command requests (queries) the programmed status of that command. When a query is sent and the power supply is addressed to talk, the response message is sent to the computer.

NOTE For complete details, see “Programming syntax” in Section 6.

1-14 Getting Started

Basic Power Supply Operation

• Test connections — Explains how to connect the device under test (DUT) to the power supply output, and how to connect an external voltage to the DVM input.

• Outputting voltage and current — Explains how to output voltage and current.

• Reading back V and I — Covers the Actual V and I display mode, which is used to measure and display the actual voltage and current being delivered to the DUT.

• Independent voltage measurements (DVM Input) — Explains how to use the digital voltmeter (DVM) to make DC voltage measurements.

• Sink operation — Explains how to use the power supply to dissipate power, rather than sourcing it.

• Programming examples — Provides two examples: one to output and read back voltage and current, and one to measure the DVM input.

2-2 Basic Power Supply Operation

Test connections

WARNING When installing a unit into a test system, make sure the external power

sources do not apply voltage to the power supply in excess of its maximum limits (see specifications). Failure to do so could result in personal injury or death.

Test connections to the power supply are made at the rear panel using a quick disconnect OUTPUT/DVM IN connector (Keithley part number CS-846). Figure 1-1B shows where the connector plugs in. Use up to #14 AWG wire for the screw terminals of the connector. Once the connector is wired up, plug it into the rear panel and tighten the captive retaining screws.

Figure 2-1 shows typical power supply connections to the device under test.

NOTE Source I/O terminals are rated up to 10A maximum per pin. Two sets of Source +

and Source - terminals are available. This configuration allows you to wire source connections in parallel to reduce the effects of wire impedance or to have two separate loads. The two Source + pins and the two Source - pins are internally connected to respective terminals on the PC board.

Figure 2-1

Typical connections

Disconnect

(Part # CS-846)

DVM Input

Output

DVM +

DVM Source -

Source -

Sense -

Sense +

Source +

Quick

Connector

External

Test

Circuitry

DUT

Outputting voltage and current

The fundamental process to output voltage and current is to 1) set the output voltage and current limit values, and 2) press the OPERATE key. The details of this process are discussed as follows.

Setting output voltage and curr ent limit

The output capabilities of the power supply are shown in Figure 2-2. Figure 2-2A shows the output capabilities for the 5A and AUTO measurement ranges. Notice that when voltage is set to more than 9V, the maximum current limit is 3A.

Figure 2-2

Output capabilities

I-Limit

Basic Power Supp ly Operation 2-3

A) 5A or AUTO Measurement Range

I-Limit

B) 5mA Measurement Range (Models 2303 and 2303B)

I-Limit

0.6A

C) 500mA Measurement Range (Model 2303-PJ)

V-Source

15V

V-Source

15V

V-Source

15V

2-4 Basic Power Supply Operation

The current limit setting for the 5 AMPS and AUTO ranges is “remembered” by that range.

For the following examples, assume the current limit setting on the 5 amps range is 3A.

Models 2303 and 2303B – Selecting the 5 MILLIAMPS range defaults the current limit setting to 1A since that is the maximum allowable setting on that range. Toggling back to the 5 amps range reinstates the 3A limit. If the current limit value on the 5 amps range is ≤1A, the limit on the 5 milliamps range will be the same when switching from the 5A range to the 5 milliamps range.

Model 2303-PJ – Selecting the 500 milliamps range defaults the current limit setting to 0.6A since that is the maximum allowable setting on that range. Toggling back to the 5 amps range reinstates the 3A limit. If the current limit value on the 5 amps range is ≤0.6A, the limit on the 500 milliamps range will be the same when switching from the 5A range to the 500 milliamps range.

Current ranges

The power supply current ranges are listed in Table 2-1. With auto range selected, the instrument will automatically go to the most sensitive range to perform the measurement.

Table 2-1

Current ranges

Power supply Current ranges

Models 2303 and 2303B Model 2303-PJ

Current range selection - The current measurement range is selected from the current range item of the menu. The menu is accessed by pressing the MENU key.

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

5A, 5mA and AUTO 5A, 500mA and AUTO

Current limit modes

If the current limit is reached, the output will either turn off (trip) or stay on (lim). The current limit can also be used to control an external relay (Section 5). The four current limit modes are summarized in Table 2-2 and explained below.

NOTE The LIMIT RELAY and TRIP RELAY modes are available in the Models 2303 and

2303B with firmware revision A06 and later. Use the FIRMWARE REVISION selection in the MAIN MENU to display the revision level.

Basic Power Supp ly Operation 2-5

Table 2-2

Front panel current limit selections

Submenu choice* Current limit effect Output state External relay state

LIMIT Current will be limited. Remains on Not affected.

TRIP Current will trip. Goes off Not affected.

LIMIT RELAY Current will be limited. Remains on Tracks current limit state.

TRIP RELAY Current will trip. Goes off Tracks current limit state.

* LIMIT RELAY and TRIP RELAY available in Models 2303 and 2303B with firmware revision level A06

and higher.

LIM mode - With the lim mode selected, the output will remain on when the current limit is reached. The “LIM” message will appear on the lower line of the display, after the current reading indicator (A or mA). The message will clear when the limit condition is cleared.

The power supply can be taken out of the current limit by decreasing the output voltage or increasing the current limit value. Note that increasing the current limit may compromise protection for the DUT.

While in the current limit, the power supply is operating as a constant-current source. As long as the limit condition exists, the power supply output current will remain constant. Note that the output voltage is probably less than the programmed value when sourcing current.

NOTE The power supply does not provide LIM mode current limiting during sink operation.

TRIP mode - With the trip mode selected, the output will turn off when the current limit is reached. The “TRIP” message will appear on the lower line of the display, after the current reading indicator (A or mA). The message will clear when the output is turned back on, assuming it does not trip again due to a current limit condition.

LIMIT RELAY mode - With the limit relay mode (Figure 2-3), the relay output turns on (ONE) when the current limit is reached, and the relay output turns off (ZERO) when the unit is not in current limit.

TRIP RELAY mode - With the trip relay mode (Figure 2-4), the relay output turns on and the power supply output turns off when the current limit is tripped, and the unit must be manually reset to turn the relay output off and the power supply output back on. If the condition that caused the trip has not be corrected, the output will trip again.

As discussed in Section 5, you can also use the OUTPUT RELAY submenu to set the relay state to ONE (relay closed) and ZERO (relay open). With current limit mode set to LIMIT or TRIP, the relay state operates independently based on the menu choice selected. However, with LIMIT RELAY and TRIP RELAY, the menu choices may be used to override the relay state and cause the relay state not to track the current limit state. For LIMIT RELAY, this condition may exist only momentary while the limiting condition still exists. TRIP RELAY allows you to clear the relay tracking while correcting the tripping condition. Once corrected and the output state is turned on, tracking will resume.

2-6 Basic Power Supply Operation

NOTE When the current limit relay control mode is selected, the relay may chatter or not

have sufficient time to pull in if the current value is fluctuating around the set current limit, depending on how rapidly the current is fluctuating around the current limit point.

Figure 2-3

Relay control mode - limit relay

Current

Relay

Off

Figure 2-4

Relay control mode - trip relay

Current

Output turns off due to Trip Mode

Limit Setting

User turns output on, and trip condition is corrected. Otherwise, output will trip again.

Relay

Off

Basic Power Supp ly Operation 2-7

Current limit mode selection - The current limit mode is selected from the current lim mode item of the menu. The menu is accessed by pressing the MENU key.

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

Procedure to edit v oltage and curr ent values

The following procedure assumes that the appropriate current range is already selected.

Editing keys — Once in the output settings mode, the four editing keys ( to set values. Cursor position (blinking digit) is controlled by the positioned on a digit, increment or decrement the value using the

ß and © keys. With the cursor ¹ and ƒ keys.

ß, ©, ¹ and ƒ) are used

Perform the following steps to edit voltage and current values:

1. Press the SET key to select the output settings mode. A blinking cursor appears in the voltage field of the display.

2. Use the

ß, ©, ¹ and ƒ keys to key in the desired output voltage value and press SET. The

blinking cursor moves to the current field of the display.

3. Use the

ß, ©, ¹ and ƒ keys to key in the desired current limit and press SET to exit from

the output settings mode.

Editing shortcuts

With the output OFF, the following editing shortcuts can be used:

• Output voltage can be quickly set to the maximum value by incrementing the tens digit (MSD). Note that if the tens digit is zero, it is not displayed. Place the cursor to the left of the units digit.

• Output voltage can be quickly set to zero (0.000 V) by decrementing the first leading zero of the reading. If there is no leading zero, decrement the tens digit.

• Current limit on the 5A range can be quickly set to its maximum value by incrementing the units digit (MSD).

• Current limit on either range can be quickly set to the minimum value (0.0001 A) by decrementing the first leading zero of the reading. If there is no leading zero, decrement the units digit.

Editing restrictions

With the output ON, the following editing restrictions are in effect:

• You cannot increment a digit that would display a value that exceeds the maximum. For example, for the value 14.200 V, you cannot increment the “1” or the “4” since the resultant value would exceed 15.000 V.

• When decrementing a digit, only that digit and digits to the left are affected. The digits to the right of the cursor are not changed.

2-8 Basic Power Supply Operation

NOTES The SET key is active in any front panel menu or display mode. If not already in the

output settings mode, the SET key will select it. The V and I DACs are updated in real time. Therefore, if the output is on, the output is updated immediately when a value is altered. After pressing SET to exit the output settings mode, the instrument returns to the previous display mode or front panel menu.

Operate

The OPERATE key is used to control the output of the power supply. This key toggles the output between on and off. While in one of the display modes, output ON or OFF is displayed in the upper right hand corner of the display. The key is active in any front panel menu or display mode. In menus, the on/off state of operate is not displayed. Note that DVM measurements can be performed with the output off.

SCPI pr ogramming — outputting v oltage and current

The commands to output voltage and current are summarized in Table 2-3. The “Outputting and reading back V and I” programming example at the end of this section demonstrates how to use these commands.

Table 2-3

SCPI commands — outputting voltage and current

Commands Description Default Ref

SENSe :CURRent :RANGe [:UPPer] <n> :AUTO

[SOURce] :VOLTage <n> :CURRent <n> :TYPe <name>

:STATe?

OUTPut [:STATe]

* LIMRELAY (LIMITRELAY) and TRIPRELAY available in Models 2303/2303B with firmware revision level A06 and higher.

SENSe subsystem: Current function: Set current measurement range: Specify expected current in amps; 0 to 5. Enable or disable auto range.

SOURce subsystem: Set voltage amplitude in volts; 0 to 15 (1mV resolution). Set current limit value in amps; 0 to 5 (100µA resolution). Select current limit type; LIMit, TRIP, LIMRELAY (LIMITRELAY), or TRIPRELAY. * Query state of current limit.

OUTPut subsystem: Turn the power supply output on or off. OFF

5.0 OFF

0.0

0.25 LIM

A B

C D E

Basic Power Supp ly Operation 2-9

A. SENSe:CURRent:RANGe <n>

1. After specifying a current value, the instrument will go to the most sensitive range to accommodate that reading. For example, if you are going to set current limit to 750mA, you can let <n> = 0.75 (or 750e-3) to select the 5A range. Another way to select a range is to use the MINimum and MAXimum parameters as follows:

SENS:CURR:RANG MIN‘ Select the low current range (5mA or 500mA).

SENS:CURR:RANG MAX‘ Select the high current range (5A).

2. Using this command to manually select the current range disables auto range.

B. SENSe:CURRent:RA NGe:A UTO

This command is coupled to the :RANGe <n> command. When auto range is enabled, the parameter value <n> for :RANGe changes to the automatically selected range value. If you then disable auto range, the instrument will remain at the automatically selected range.

C. V OL Tage <n>

1. If the present current limit value is above 3A, setting the output voltage above 9V will automatically default the current limit to 3A.

2. The response to VOLTage? is affected by the GPIB output format. For decimal formats, the response has three decimal places, otherwise it is in exponential format (see Section 10 for details).

D. CURRent <n>

1. 5A or AUTO measurement range selected - With output voltage set to ≤9V, the maximum current limit value is 5A. With voltage set to >9V, the maximum current limit is 3A.

2. Models 2303 and 2303B:

• With the 5mA measurement range selected, the maximum current limit is 1A.

• Sending a value that exceeds 1A is rejected, and the following message is displayed

briefly:

CURRENT LIMIT ON

mA RANGE <= 1A

3. Model 2303-PJ:

• With the 500mA measurement range selected, the maximum current limit is 0.6A.

• Sending a value that exceeds 0.6A is rejected, and the following message is displayed

briefly:

CURRENT LIMIT ON

mA RANGE <= 0.6A

4. The response to CURRent? is affected by the GPIB output format. For decimal formats, the response has four decimal places, otherwise it is in exponential format (see Section 10 for details).

2-10 Basic Power Supply Operation

E. CURRent:TYPe <name>

Parameters are summarized in Table 2-4 and described as follows:

1. With the LIMit type selected, the output will remain on when the current limit is reached.

2. With the TRIP mode selected, the output will turn off when the current limit is reached.

3. With the LIMRELAY (or LIMITRELAY) mode (Figure 2-3), the relay output turns on (ONE) when the current limit is reached, and the relay output turns off (ZERO) when the unit is not in current limit.

4. With the TRIPRELAY mode (Figure 2-4), the relay output turns on and the power supply output turns off when the current limit is tripped, and the unit must be manually reset to turn the relay output off and the power supply output back on. If the condition that caused the trip has not be corrected, the output will trip again. Note that you can also use the OUTPut:RELay command to set the relay state (see Section 5). The parameter choices are ONE and ZERO. With the current limit mode set to LIMit or TRIP, the relay state operates independently based on the command parameter. However, with LIMRELAY (or LIMITRELAY) and TRIPRELAY, the command parameters may be used to override the relay state and cause the relay state not to track the current limit state. For LIMRELAY, this condition may occur only momentary while the limiting condition still exists. With TRIPRELAY, this condition allows you to clear the relay tracking while correcting the tripping condition. Once corrected, and the output state is turned ON, tracking will resume.

F. CURRent:STATe?

1. With the LIMit type selected, this command returns a “1” if the power supply is operating as a constant-current source (current limit reached). With the TRIP type selected, a “1” is returned if the output has turned off (tripped) due to current limit being reached. It will clear to “0” when the output is turned back on.

2. The operation event register can be read to determine if the power supply is in current limit and if the output has tripped (turned off) as a result of the current limit condition. See Section 7 for details.

Table 2-4 Current limit type (CURRent:TYPe) command parameters

Parameter choice Current limit effect Output state External relay state

LIMit Current will be limited. Remains on Not affected.

TRIP Current will trip. Goes off Not affected.

LIMRELAY or LIMITRELAY

TRIPRELAY Current will trip. Goes off Tracks current limit state.

Current will be limited. Remains on Tracks current limit state.

Reading back V and I

Actual V and I displa y mode

Measured output voltages and currents are displayed with the actual V and I display mode

selected. This display mode is selected as follows:

NOTE If output settings are presently being displayed (as denoted by a blinking digit in the

voltage or current field), keep pressing the SET key until the blinking stops. The instrument can now display measured readings.

1. Press the DISPLAY key to access the display menu.

2. Press the

3. Press ENTER. Voltage readings are located on the top line of the display, and current readings are located on the bottom line.

NOTE For details on display modes, see “Display modes” in Section 1.

Measurement configur ation

¹ or ƒ key until “ACTUAL V AND I” is displayed.

Basic Power Supply Operation 2-11

CURRENT RANGE, INTEGRATION RATE and the AVERAGE READINGS count can be

checked or changed from the menu (which is accessed by pressing the MENU key).

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

Current range

Current range is linked with current limit. Therefore, as a general rule, the user selects the current range before setting the current limit. The current range can be changed at any time, but selecting the lower range may change the current limit setting. See “Outputting voltage and current” (in this section) for details on current range and current limit.

Integration r ate

The integration (reading) rate of the instrument is specified as a parameter based on the number of power-line cycles (NPLC), where 1 PLC for 60Hz line frequency is 16.67msec (1/60). In general, the fastest integration time (0.01 PLC) results in increased reading noise. The slowest integration time (10 PLC) provides the best common-mode and normal-mode rejection. In-between settings are a compromise between speed and noise.

The INTEGRATION RATE item of the menu is also used to set the reading rate for DVM measurements. Note that it is not used to set the integration rate for pulse current and long integration measurements. These measurements are covered in Sections 3 and 4, respectively.

2-12 Basic Power Supply Operation

Av erage r eadings

The average reading count (1 to 10) specifies the number of measurement conversions to average for each reading. For example, with a reading count of 5, each displayed reading will be the average of five measurement conversions.

The AVERAGE READINGS item of the menu is also used to set the average reading count for DVM measurements. Note that it is not used to set the average reading count for pulse current and long integration measurements. These measurements are covered in Sections 3 and 4, respectively.

SCPI progr amming — measure V and I, and D VM input

The commands to measure output voltage and current, and the DVM input are summarized in Table 2-5. The “Programming examples” at the end of this section demonstrates how to use these commands.

Table 2-5

SCPI commands — measure V and I, and DVM input

Commands Description Default Ref

SENSe :FUNCtion <name>

:NPLCycles <n>

:AVERage <NRf>

SENSe subystem: Select readback function; “VOLTage”, “CURRent”, or “DVMeter”. Set integration rate (in line cycles) for voltage, current, and DVM measurements; 0.01 to 10. Specify the average count for voltage, current, and DVM measurements; 1 to 10.

VOLT

1.0

READ? READ:ARRay?

A. SENSe:FUNCtion <name>

B. SENSe:AVERage <NRf>

Trigger and return one reading. Trigger an array of readings and return them.

1. The parameter name can instead be enclosed in single quotes (e.g., ‘CURRent’).

2. With “DVMeter” selected, the instrument measures the voltage applied to the input of the digital voltmeter (DVM).

3. The “PCURrent” and “LINTegration” parameters for :FUNCtion (which are not listed in Table 2-5) select the pulse current and long integration measurement modes. These measurement modes are covered in Sections 3 and 4, respectively.

1. When requesting a single reading (FETch?, READ?, or MEASure?), average count

specifies the number of measurement conversions to average for the reading. For example, with the average count set to 10, READ? will trigger 10 measurement conversions and return (and display) the average of those 10 conversions.

B B

Basic Power Supply Operation 2-13

2. When requesting an array of readings (FETCh:ARRay?, READ:ARRay? or MEASure:ARRay?), average count specifies the number of measurements to place in an array. For example, with the average count set to 10, READ:ARRay? will trigger and return 10 readings.

3. Signal oriented measurement commands (e.g., READ?) are covered in Section 9.

Independent voltage measur ements (D VM)

The power supply has an independent digital voltmeter (DVM) that can measure up to

+20VDC. Connections for the DVM are shown in Figure 2-1.

D VM input displa y mode

The DVM input display mode must be selected in order to measure voltage applied to DVM

input of the power supply. This display mode is selected as follows:

NOTE If output settings are presently being displayed (as denoted by a blinking digit in the

voltage or current field), keep pressing the SET key until the blinking stops. The instrument can now display measured readings.

1. Press the DISPLAY key to access the display menu.

2. Press the

3. Press ENTER.

¹ or ƒ k ey until “DVM INPUT” is displayed.

NOTE For details on display modes, see “Display modes” in Section 1.

Measurement configur ation

The INTEGRATION RATE and AVERAGE READINGS count for DVM measurements can

be checked or changed from the menu (which is accessed by pressing the MENU key).

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

These two measurement configuration menu items are the same ones used for actual V and I measurements. See “Reading back V and I, Measurement configuration” for details on integration rate and average reading count.

SCPI progr amming — D VM

The commands to perform actual V and I measurements are also used to perform DVM measurements. These commands are documented in Table 2-5.

The “DVM measurements” programming example at the end of this section demonstrates how to use these commands to measure the DVM input.

2-14 Basic Power Supply Operation

Sink operation

Whenever a test circuit sources a voltage that exceeds the programmed supply voltage, the power supply automatically becomes a sink instead of a source. It then dissipates power instead of supplying power, while continuing to maintain the programmed supply voltage at its terminals. Current (I Current readback is negative.

NOTE During sink operation, the power supply does not regulate current. It acts only as a

constant voltage load, not as a constant current load.

Figure 2-5 illustrates an application for sink operation. In Figure 2-5, the test circuit is a battery charging circuit; the power supply acts as a constant voltage battery load.

) flows into the positive (+) terminal of the power supply rather than out of it.

sink

Figure 2-5

Sink operation example

3.0V

Charger Circuit

I sink

4.2V

Power Supply

To keep the power supply in the current sink mode, safely, maintain the following condition:

• Ensure that the test circuit voltage remains greater than the programmed supply voltage.

• Ensure that the maximum sink current falls within the limits specified in Table 2-6.

Table 2-6Table 2-6

Sink current limits

Programmed supply voltage

Maximum allowable sink current

0V to 5V 2.0A

5V to 15V 2.0A - [0.1A/V) × (Programmed supply voltage - 5V)]

CAUTION During sink operation, the current limit circuit of the power supply is not

operational, because it only limits current by limiting power supply output voltage. During sink operation, your test circuit supplies net input voltage, over which the power supply has no control. Therefore, you must ensure that your test circuit sources current within the limits of Table 2-6. Failure to source current within the limits of Table 2-6 can cause damage to the power supply that is not covered by the warranty.

Progr amming examples

Outputting and reading back V and I

The following command sequence demonstrates how to output voltage and current, and read

back (measure) the actual voltage and current:

VOLT 5 ‘ Set output voltage to 5V. SENS:CURR:RANG:AUTO ON ‘ Enable auto range for current. CURR 750e-3 ‘ Set current limit to 750mA. CURR:TYPE TRIP ‘ Select Trip mode for current limit. SENS:FUNC ‘VOLT’ ‘ Select the voltage measurement function. SENS:NPLC 2 ‘ Set integration rate to 2 PLC. SENS:AVER 5 ‘ Set average reading count to 5. OUTP ON ‘ Turn on the power supply output. READ? ‘ Trigger 5 voltage measurement conversions

SENS:FUNC ‘CURR’ ‘ Select current measurement function. READ? ‘ Trigger 5 current measurement conversions and

Basic Power Supply Operation 2-15

and return the average of those

return the average of those 5 conversions.

5 conversions.

D VM measure ments

The following command sequence demonstrates how to measure voltage applied to the DVM

input of the power supply:

SENS:FUNC ‘DVM’ ‘ Select the DVM Input function. SENS:NPLC 5 ‘ Set integration rate to 5 PLC. SENS:AVER 10 ‘ Set average reading count to 10. READ:ARR? ‘ Trigger and return 10 readings.

2-16 Basic Power Supply Operation

Pulse Current Measurements

• Overview — Provides an overview of the pulse current measurement process.

• Measurement conﬁguration — Explains how to conﬁgure the instrument for pulse cur-

rent measurements.

• Pulse current measurement procedure — Provides the step-by-step procedure to per-

form pulse current measurements from the front panel.

• SCPI programming — Documents the commands used to program the instrument for

pulse current measurements, and covers pulse current digitization (which can only be performed over the GPIB). Two programming examples are provided; one for pulse current measurements and one for pulse current digitization.

3-2 Pulse Current Measurements

Overview

The power supply can perform current measurements for pulsing loads. The built-in measurements include:

• Peak measured current — measures the peak (high) current of the pulse train.

• Idle measured current — measures the idle (low) current of the pulse train.

• Average transmit current — measures the average current of the pulse train.

NOTE For Models 2303 and 2303B, pulse-measurements are automatically performed on

the 5A range. For Model 2303-PJ, pulse-current measurements can be performed on either the 5A range or 500mA range.

The high, low, and average measurements of a pulse are illustrated in Figure 3-1. The high measurement is triggered on the rising edge of the pulse, and an integration is performed for the time speciﬁed for the high measurement. The falling edge of the pulse triggers the low measurement, and an integration is performed for the time speciﬁed for the low measurement. An average measurement is triggered on the rising edge, and the integration is speciﬁed by the average measurement time setting.

NOTE Another measurement of pulse currents, digitization, is available over the bus. Refer

to “Pulse current digitization” in “SCPI programming” for details.

Figure 3-1

Pulse current measurement

High Low

Average

High and average measurement triggered on leading edge of pulse

Low measurement triggered on falling edge of pulse

Trigger level

To avoid false pulse detection, you can use a trigger level of up to 5A. All pulses, noise, or other transients that are less than the set trigger level will be ignored. For Models 2303 and 2303B, the maximum trigger level is 5A. For Model 2303-PJ, the trigger level can be set for each measurement range. For the 5A range the maximum trigger level is 5A, and for the 500mA range, the maximum trigger level is 500mA.

Trigger delay

When a pulse is detected, there is a 25µsec code execution delay before the integration period begins. An additional trigger delay can be used to allow leading edge pulse overshoot to settle. The integration period will not start until the trigger delay period expires. Note that a large trigger delay will slow down power supply operation.

Integration times

The three integration time periods for pulse measurements can be set automatically or manually by the user. When the pulse auto time operation is performed, the instrument measures the high and low periods of the detected pulse and sets appropriate integration times. The pulse average time is set to the sum of the measured high and low times. The three integration times apply for all subsequent pulse measurements until another pulse auto time is performed or the times are changed manually. The pulse auto time feature can detect pulses in the 80µsec to 833msec range.

Pulse Current Measurements 3-3

You can manually set the PULSE HIGH TIME, PULSE LOW TIME, and PULSE AVG TIME. In general, the longer the integration period, the more accurate the measurement. However, you must make sure an integration period does not extend into the wrong portion of the pulse or into the next pulse. For example, if the pulse is high for 600µsec, the high integration time must be ≤600µsec. If not, you will integrate a low portion of the pulse, and the high pulse measurement will therefore be erroneous. Be sure to factor in trigger delay when determining integration times.

Average readings count

The average readings count speciﬁes how many measurements (integrations) are performed and averaged for each displayed reading. For example, assume that the pulse average readings count is 10 and you are measuring PULSE HIGH. Each displayed reading will reﬂect the average of 10 peak pulse measurements.

3-4 Pulse Current Measurements

Measurement conﬁguration

NOTE Current range is selected from the CURRENT RANGE item of the menu. Integration

times, average readings count, trigger delay and trigger level are set from the PULSE CURRENT item of the menu. Details on integration rate, average readings count, trigger delay and trigger level are provided in the “Overview”.

Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow the table.

Current range

For pulse current measurements, the AUTO range selection is functionally a no-op (no oper-

ation). The instrument will not autorange with the pulse current measurement function selected.

For Models 2303 and 2303B, pulse current measurements are performed on the 5A range,

regardless of the range selection.

For Model 2303-PJ, pulse current measurements are performed on which ever range the

instrument is on when the pulse current measurement function is selected.

Current range is linked to current limit. Therefore, as a general rule, the user selects the current range before setting the current limit. See “Outputting voltage and current” (in Section 2) for details on current range and current limit. Current range is selected from CURRENT RANGE item of the menu.

Integration times

Use the following items of the PULSE CURRENT menu item to set integration times:

• HIGH TIME — Use to set the integration period (in µsec) for high pulse-current mea-

surements.

• LOW TIME — Use to set the integration period (in µsec) for low pulse-current

measurements.

• AVERAGE TIME — Use to set the integration period (in µsec) for average

pulse-current measurements.

• AUTO TIME — Use to automatically set the integration times for high, low, and average

pulse-current measurements. These times are based on detecting the pulse and remain until another auto time is performed or the times are manually changed.

Average readings count

Use the AVERAGE READINGS item of the PULSE CURRENT menu item to set the average readings count. This count speciﬁes the number of measurements (integrations) to average for each reading. For example, with reading count set to 10, each displayed reading will reﬂect the average of 10 pulse current measurements.

Trigger delay and trigger level

Use the following items of the PULSE CURRENT menu item to set trigger delay and trigger level:

• TRIGGER DELAY — Use to specify additional trigger delay (0 to 100msec in 10µsec

steps). See “Trigger delay” for details.

• TRIGGER LEVEL — Use to set the trigger level. Pulses less than the speciﬁed level

are not detected.

Models 2303 and 2303B – Set the trigger level from 0 to 5A in 5mA steps. However, there is approximately 10mA of trigger hysteresis built into the hardware. Therefore, if a pulse does not exceed this level, trigger detection will not occur.

Model 2303-PJ – The trigger level can be set for either the 5A or 500mA range. For the 5A range, the trigger level can be set from 0 to 5A in 5mA steps. For the 500mA range, the trigger level can be set from 0 to 500mA in 0.5mA steps. However, there is trigger hysteresis built into the hardware. For the 5A range, trigger hysteresis is approximately 10mA, and for the 500mA range, trigger hysteresis is approximately 1mA. If a pulse does not exceed the appropriate hysteresis level, trigger detection will not occur.

The two trigger level ranges for Model 2303-PJ are displayed as follows: 5A Range: PULSE TRIG LEVEL

A (5.0) 0.000A

500mA Range: PULSE TRIG LEVEL

mA (500) 0.0000 A

To toggle the range for the trigger level, place the blinking cursor on the “A” at the far right end of the display, and press the amps), pressing ENTER updates the displayed range for that trigger level.

Pulse Current Measurements 3-5

 or  key. After keying in the trigger level (in

Pulse current display mode

Pulse current measurements are displayed with the pulse current display mode selected. This display mode is selected as follows:

NOTE If output settings are presently being displayed (as denoted by a blinking digit in the

voltage or current ﬁeld), keep pressing the set key until the blinking stops. The instrument can now display measured readings.

3-6 Pulse Current Measurements

1. Press the DISPLAY key to access the display menu.

2. Press the

3. Use the

 or  key until “PULSE CURRENT” is displayed and press ENTER.

 or  key to display the desired pulse measurement; high, low or average.

NOTE For details on display modes, see “Display modes” in Section 1.

Pulse current measurement procedure

The following steps summarize the procedure to perform pulse measurements:

1. For Model 2303-PJ, select the desired measurement range (5A or 500mA) from the CURRENT RANGE item of the menu. For Models 2303 and 2303B, pulse measurements are automatically performed on the 5A range.

2. From the PULSE CURRENT item of the menu, set the trigger level and delay, integration times, and average readings count.

3. As explained in Section 2, set the output voltage and current limit, and press OPERATE.

4. Press the DISPLAY key and select the PULSE CURRENT display type.

5. Use the LOW, or PULSE AVG.

NOTES If no pulses are detected, current will not be measured (i.e. -----A) and the “NO

 or  key to display the desired pulse measurement: PULSE HIGH, PULSE

PULSE” message will be displayed. The “NO PULSE” message is displayed with dashes or the last valid pulse reading. Dashes are shown if the pulse-current measurement settings are not appropriate for detecting pulses. The last valid pulse is shown if the pulse disappears while taking background readings and no change in pulse settings was made.

Pulses are not detected with the output off. With the output on, pulses will not be detected if the trigger level is too low or too high. Perform the following procedure to ﬁnd an appropriate trigger level. Make sure the voltage and current settings are appropriate for detecting pulses.

Determining correct trigger level (pulse current)

1. If using Model 2303-PJ, make sure it is on the same current range (5A or 500mA) that is being used for pulse measurements (step 1 of the “Pulse current measurement procedure”).

2. Turn on the output.

3. Select the pulse current display type. If the trigger level is too low or too high, the “NO PULSE” message will be displayed. If pulse current measurements are instead being displayed, the trigger level is valid. You can skip the rest of this procedure.

4. Go into the menu, select PULSE CURRENT, and then TRIGGER LEVEL.

5. Change the PULSE TRIG LEVEL and press ENTER. If the trigger level is still too low or too high, the “A/D PULSE TRIG NOT DETECTED” message will be displayed brieﬂy. Note that it may take a few seconds for the message to appear.

6. If the message appeared, repeat step 5 until a valid trigger level is found.

7. Use the MENU key to back out of the menu structure and display pulse current measurements.

Pulse Current Measurements 3-7

SCPI programming

Table 3-1

SCPI commands — pulse current measurements

Commands Description Default Ref

SENSe :FUNCtion “PCURrent” :PCURrent :AVERage <NRf>

:MODE <name>

:TIME :AUTO :HIGH <NRf>

:LOW <NRf>

:AVERage <NRf>

:SYNChronize [:STATe]

:TLEVel <NRf>

:TLEVel [:AMPs] <NRf> :MILLiamp <NRf>

:DELay <NRf>

READ? READ:ARRay?

SENSe subystem:

Select pulse current measurement function. Pulse current conﬁguration:

Specify average count; 1 to 100, or 1 to 5000 (pulse current digitization). Select measurement mode; HIGH, LOW or AVERage. Set integration times:

Integration times set automatically. Specify integration time (in sec) for high pulse measurements; 33.33e-6 to 0.8333. Specify integration time (in sec) for low pulse measurements; 33.33e-6 to 0.8333. Specify integration time (in sec) for average pulse measurements; 33.33e-6 to 0.8333.

Pulse detection triggering:

Send ON to select pulse current measurements. OFF selects pulse current digitization. Models 2303 and 2303B - Set trigger level in amps; 0 to 5. Model 2303-PJ trigger level:

Set trigger level (in amps) for 5A range; 0 to 5. Set trigger level (in amps) for 500mA range; 0

to 0.5. Specify trigger delay in seconds; 0 to 0.1 or 0 to 5 (pulse current digitization).

Trigger and return one reading. Trigger an array of readings and return them.

VOLT

HIGH

3.333e-5

0.0

B B

3-8 Pulse Current Measurements

A. SENSe:FUNCtion ‘PCURrent’

The parameter name can instead be enclosed in single quotes (as shown above).

B. SENSe:PCURrent:AVERage <NRf>

1. When requesting a single reading (FETch?, READ?, or MEASure?), average count speciﬁes the number of pulse current measurement conversions to average for the reading. For example, with the average count set to 10, READ? will trigger 10 pulse current measurement conversions and return (and display) the average of those 10 conversions.

2. When requesting an array of readings (FETCh:ARRay?, READ:ARRay? or MEASure:ARRay?), average count speciﬁes the number of pulse current measurements to place in an array. For example, with the average count set to 10, READ:ARRay? will trigger and return 10 readings.

3. For pulse current digitization, use an array reading command (such as READ:ARRay?) to return the digitized readings.

4. Signal oriented measurement commands (e.g., READ?) are covered in Section 9.

C. SENSe:PCURrent:TIME

The response for the query commands (:HIGH?, :LOW? and :AVERage?) is affected by the GPIB output format. For decimal formats, the response has four decimal places, otherwise it is in exponential format. See Section 6 to select the output format.

D. SENSe:PCURrent:SYNChronize

Boolean parameters:

• ON or 1 - Enables trigger synchronization for pulse current measurements. A pulse

current reading will not trigger until the speciﬁed trigger level is detected and the speciﬁed trigger delay period expires.

• OFF or 0 - Disables trigger synchronization and selects pulse current digitization. See

“Pulse current digitization” for details on digitizing a current pulse or waveform.

E. :TLEVel Commands

A valid trigger level for detecting the pulse is needed whether trigger synchronization is ON or OFF (see Ref D).

F. SENSe:PCURrent:SYNChronize:DELay <NRf>

1. The smallest step size for trigger delay is 10µsec. If you specify a smaller step size, it is adjusted up to the next 10µsec step value (e.g., 43µsec is adjusted up to 50µsec).

2. There is an internal trigger delay of 25µsec after pulse detection (for code execution), to triggering the ﬁrst reading.

Pulse current digitization

The following discussion explains how to digitize a current waveform. A programming example at the end of this section demonstrates proper command sequence for pulse current digitization.

With pulse current digitization selected, readings are taken at a constant integration time of 33µsec across the pulse or pulse train. The message “DIGITIZE” is displayed instead of readings. Pulse current digitization is selected by disabling trigger synchronization:

SENS:PCUR:SYNC

= OFF Select pulse current digitization (trigger synchronization disabled).

= ON Select pulse current measurements (trigger synchronization enabled).

The commands to set the trigger level and trigger delay for pulse current measurements also apply for pulse current digitization. However the trigger delay can be set up to ﬁve seconds.

SENS:PCUR:SYNC:DEL <NRf>

<NRf> = 0 to 5 Trigger digitization delay in seconds (10µsec steps).

Note that the “NO PULSE” message will be displayed if the pulse is not detected.

Pulse Current Measurements 3-9

When the pulse is detected, the digitization process syncs up to the edge speciﬁed by the following command:

SENS:PCUR:MODE <name>

<name> = HIGH or AVER Sync up to rising edge of pulse. = LOW Sync up to falling edge of pulse.

After any speciﬁed delay period expires, the instrument takes the number of readings speciﬁed by the average count command:

SENS:PCUR:AVER <NRf>

<NRf> = 1 to 5000 Digitize 1 to 5000 readings.

NOTE Although the integration time is 33µsec, some processing time is needed between

readings. The time between readings, including integration and processing time, is about 278µsec.

3-10 Pulse Current Measurements

Programming examples

Pulse current measurements

The following command sequence will return the average of 10 peak pulse current measurements:

SENS:RANG 5 ‘ Select 5A range. VOLT 15 ‘ Set output voltage to 15V. CURR 0.75 ‘ Set current limit to 750mA. OUTP ON ‘ Turn output on. SENS:PCUR:AVER 10 ‘ Set average count to 10. SENS:PCUR:TIME:AUTO ‘ Set integration times automatically. SENS:PCUR:SYNC:TLEV 0.1 ‘ Set trigger level to 100mA. SENS:PCUR:SYNC:DEL 50e-3 ‘ Set trigger delay to 50msec. SENS:FUNC “PCUR” ‘ Select pulse current function. SENS:PCUR:SYNC ON ‘ Enable trigger synchronization. SENS:PCUR:MODE HIGH ‘ Configure to measure peak pulse. READ? ‘ Trigger 10 measurement conversions and

Pulse current digitization

The following command sequence returns 3600 digitized readings. It will take approximately

one second to perform the measurement process.

‘ return the average of those 10 conversions.

SENS:RANG 5 ‘ Select 5A range. VOLT 15 ‘ Set output voltage to 15V. CURR 0.75 ‘ Set current limit to 750mA. OUTP ON ‘ Turn output on. SENS:PCUR:SYNC OFF ‘ Disable trigger synchronization. SENS:PCUR:AVER 3600 ‘ Set average count to 3600. SENS:PCUR:SYNC:TLEV 0.1 ‘ Set trigger level to 100mA. SENS:PCUR:SYNC:DEL 50e-3 ‘ Set trigger delay to 50msec. SENS:FUNC “PCUR” ‘ Select pulse current function. READ:ARR? ‘ Trigger and return 3600 readings.

Long Integration Measurements

• Overview — Provides an overview of the long integration measurement process.

• Measurement conﬁguration — Explains how to conﬁgure the instrument for long inte-

gration measurements.

• Long integration measurement procedure — Provides the step-by-step procedure to

perform long integration measurements from the front panel.

• SCPI programming — Documents the commands used to program the instrument for

long integration measurements. Included is a programming example to perform long integration measurements.

4-2 Long Integration Measurements

Overview

Long integration is an average measurement of one or more pulses. The integration time period can be as long as 60 seconds. Since long integration is an average measurement, the integration time period should be a complete period, or integral number of periods for a pulse train.

NOTE For Models 2303 and 2303B, long integration current measurements are automatical-

ly performed on the 5A range. For Model 2303-PJ, pulse current measurements can be performed on either the 5A range or 500mA range.

Long integration measurement is accomplished by taking an integral number of integration cycles during the total measurement time. An integration cycle is the line cycle period (16.67ms for 60Hz) plus a small processing time.

The system calculates the number of integration cycles required based on the total time and rounds down to the nearest integer. Therefore, the actual measurement time can be slightly less than the requested measurement time by up to one line cycle time.

Long integration is a technique to extend the capabilities of the power supply A/D circuit beyond its maximum integration time period. The A/D can measure pulses up to 833ms. To extend this time period for longer pulses, the long integration technique uses a ﬁltered and sampled measurement of the waveform. This gives the power supply the ability to measure signals with periods up to 60 seconds.

The ﬁltering of the waveform adds some restrictions to the types of pulses being measured. If a pulse train has a high duty cycle, where the off time is less than 200ms, the ﬁrst period of the measured waveform will not have settled to steady state, therefore it will be an inaccurate measurement. In all cases where the off or low time is less than 200ms, the ﬁltered pulse will have reached steady state in the second cycle of the waveform and, therefore, can be accurately measured. In other words, to measure a periodic waveform with low times less than 200ms (high duty cycle), start measurements after the ﬁrst period occurs. This is not a problem for one-shot pulses or for pulses with off times greater than 200ms.

The long integration measurement can be triggered to start on the rising or falling edge of a detected pulse. A third option, neither edge, lets you start the long integration measurement as soon as the long integration function is selected (assuming the output is on). This option does not need a valid trigger level to generate a reading. It will perform a measurement and produce a reading of the current even if a pulse is not present. Therefore, with NEITHER selected, the NO PULSE message will not appear on the display.

Integration time

The integration time period can be set automatically or manually by the user. The integration time can be as long as 60 seconds. For 60Hz power line frequency, the minimum integration time setting is 850msec. For 50Hz power line frequency, the minimum integration setting is 840msec.

Use AUTO TIME when you want to perform a long integration measurement of each pulse. When the AUTO TIME operation is performed, the instrument measures the time between two rising pulse edges and sets an appropriate integration time that will encompass the high and low periods of the pulse. This integration time applies for all subsequent long integration measurements until another AUTO TIME is performed or the time is changed manually.

If you want the integration period to encompass two or more pulses, you will have to set the integration time manually. However, you must make sure that the integration period does not extend into a pulse that you do not want measured. For example, if you want a long integration of two pulses, you must make sure that the set integration time does not extend into the third pulse.

Trigger edge

A pulse edge can be used to trigger the start of the measurement. Either a RISING pulse edge or a FALLING pulse edge can start the measurement. A third option is available if you do not want measurements controlled by pulse edges. With NEITHER selected, measurements start as soon as the long integration function is selected.

Long Integration Measurements 4-3

A pulse has to be detected before a RISING or FALLING pulse edge can trigger a long integration measurement. All pulses that are less than the speciﬁed trigger level are ignored (see “Trigger level”). Pulse edges are ignored while a long integration is in process. No pulse detection is needed if NEITHER trigger edge is selected.

Trigger level

Before a rising or falling pulse edge can trigger the start of a long integration, the pulse must ﬁrst be detected. Trigger level speciﬁes the minimum pulse level that will cause detection. For example, if the trigger level is set for 2A, pulses that are (≥2A will be detected. Current pulses <2A are ignored.

For Models 2303 and 2303B, the maximum trigger level is 5A. For Model 2303-PJ, the trigger level can be set for each measurement range. For the 5A range the maximum trigger level is 5A, and for the 500mA range, the maximum trigger level is 500mA.

4-4 Long Integration Measurements

Pulse timeout

PULSE TIMEOUT applies only to long integration measurements that are conﬁgured to be triggered by rising or falling pulse edges. After the long integration function is selected, the instrument searches for a pulse. If a pulse is not detected within the speciﬁed time (pulse timeout), the “NO PULSE” message will be displayed. While the “NO PULSE” message is displayed, the instrument continues to search for a pulse. With a long timeout setting, the instrument may appear locked up while it is searching for the pulse to start the long integration. PULSE TIMEOUT can be set from 1.000 to 63.000 seconds.

NOTE For GPIB operation, the search after the timeout can be disabled (see the :SEARch

command in Table 4-1).

With neither trigger edge selected, pulse timeout is not used and a pulse search is not conducted. Therefore, the “NO PULSE” message is never displayed. Measurements start as soon as the long integration function is selected, even if no pulse is present. It is the responsibility of the user to determine if a pulse was present when the measurement was made.

NOTE For GPIB operation, there is a fast readings mode that can be used with long integra-

tion functionality (see the :FAST command in Table 4-1).

Measurement conﬁguration

NOTE Current range is selected from the CURRENT RANGE item of the menu. Integration

time, trigger edge, trigger level and pulse timeout are set from the LONG INTEGRATION item of the menu. Details on integration time, trigger edge, trigger level, and pulse timeout are provided in the “Overview”.

Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow the table.

Current range

For long integration measurements, the AUTO range selection is functionally a no-op (no operation). The instrument will not autorange with the long integration measurement function selected.

For Models 2303 and 2303B, long integration measurements are performed on the 5A range, regardless of the range selection.

For Model 2303-PJ, long integration measurements are performed on which ever range the instrument is on when the long integration measurement function is selected.

Integration time

Use the following items of the LONG INTEGRATION menu item to set the integration time:

Integration time

Manually set the long integration time. For 60Hz power line frequency, integration time can be set from 850msec to 60 sec. For 50Hz power line frequency, integration time can be set from 840msec to 60 sec.

Auto time

Use to automatically set the integration time. When the AUTO TIME operation is performed, the instrument measures the time between two rising pulse edges and sets an appropriate integration time that will encompass the high and low periods of a single pulse.

Pulse timeout

Use the following item of the LONG INTEGRATION menu item to set pulse timeout:

Pulse timeout

Set pulse timeout (from 1 to 63 seconds) for long integration measurements that are conﬁgured to be triggered by rising or falling pulse edges. If a pulse is not detected within the speciﬁed time (pulse timeout), the “NO PULSE” message will be displayed. While the “NO PULSE” message is displayed, the instrument continues to search for a pulse.

Long Integration Measurements 4-5

Trigger edge and trigger level

Use the following items of the LONG INTEGRATION menu item to set trigger edge and trigger level:

Trigger edge

A pulse edge can be used to trigger the start of the measurement. Select RISING to use a rising pulse edge to start the measurement. Select FALLING to use a falling pulse edge to start the measurement. A third option is available if you do not want measurements controlled by pulse edges. With NEITHER selected, measurements will start as soon as the long integration function is selected. Note that a pulse has to be detected before a rising or falling pulse edge can trigger a long integration measurement (see “Trigger Level”).

Trigger level

Before a rising or falling pulse edge can trigger the start of a long integration, the pulse must ﬁrst be detected. Trigger level speciﬁes the minimum pulse level that will cause detection.

Models 2303 and 2303B – Set the trigger level from 0 to 5A in 5mA steps.

Models 2303-PJ – The trigger level can be set for either the 5A or 500mA range. For the 5A

range, the trigger level can be set from 0 to 5A in 5mA steps. For the 500mA range, the trigger level can be set from 0 to 500mA in 0.5mA steps.

4-6 Long Integration Measurements

The two trigger level ranges for Model 2303-PJ are displayed as follows:

5A Range: PULSE TRIG LEVEL

500mA Range: PULSE TRIG LEVEL

To toggle the range for the trigger level, place the blinking cursor on the “A” at the far right end of the display, and press the ENTER updates the displayed range for that trigger level.

Long integration display mode

Long integration measurements are displayed with the long integration display mode selected. This display mode is selected as follows:

A (5.0) 0.000A

mA (500) 0.0000 A

 and  key. After keying in the trigger level (in amps), pressing

NOTE

NOTE For details on display modes, see “Display modes” in Section 1.

If output settings are presently being displayed (as denoted by a blinking digit in the

voltage or current ﬁeld), keep pressing the SET key until the blinking stops. The instrument can now display measured readings

1. Press the DISPLAY key to access the display menu.

2. Press the

 or  key until “LONG INTEGRATION” is displayed and press ENTER.

Long integration measurement procedure

The following steps summarize the procedure to perform long integration current measurements:

1. For Model 2303-PJ, select the desired measurement range (5A or 500mA) from the CURRENT RANGE item of the menu. For Models 2303 and 2303B, long integration measurements are automatically performed on the 5A range.

2. From the LONG INTEGRATION item of the menu, set integration time, pulse timeout, trigger edge and trigger level (if appropriate).

NOTE If you select AUTO TIME to set the integration time, the pulse timeout message

“LONG INT TRIG NOT DETECTED” will occur before the output is turned on (step

3). This message indicates that the integration time has not been updated. To update the integration time, you will have to again select AUTO TIME after the output is turned on in step 3.

Setting the trigger level with the output off will also cause the pulse timeout message to appear. However, the trigger level will be set.

3. Set the output voltage and current limit, and press OPERATE.

4. Press the DISPLAY key and select the LONG INTEGRATION display type.

5. Observe the long integration readings on the display.

Long Integration Measurements 4-7

General notes

• Make sure the voltage and current settings are appropriate for detecting pulses.

• If a pulse timeout occurs (no pulses detected), current will not be measured (i.e. ----A) and the “NO PULSE” message will be displayed. Pulses are not detected with the output off. With the output on, pulses will not be detected if the trigger level is too low or too high. Perform the “Determining correct trigger level” procedure to ﬁnd an appropriate trigger level.

• While the “NO PULSE” message is displayed, the instrument continues to search for a pulse. The search can be terminated by pressing any front panel key. The “NOT TRIG” message replaces the “NO PULSE” message. To restart the search, press any arrow key while displaying long integration readings. The timeout or pulse detection will need to elapse before the display changes.

• To stop taking long integration readings, press any front panel key. As long as the instrument remains in the long integration display state, the measurement process can be resumed by pressing an arrow key. While readings are not being taken, the bottom line displays the last valid long integration reading, or dashes if no pulse detected before being stopped.

Determining correct trigger level (long integration)

1. If using Model 2303-PJ, make sure it is on the same current range (5A or 500mA) that is being used for long integration measurements (step 1 of the “pulse current measurement procedure”).

2. After selecting the appropriate voltage and current values, turn on the output.

3. Select the long integration display type. If the trigger level is too low or too high, the “NO PULSE” message will be displayed. If long integration measurements are instead being displayed, the trigger level is valid. You can skip the rest of this procedure.

4. Go into the menu, select LONG INTEGRATION, and then TRIGGER LEVEL.

5. Adjust the trigger level and press ENTER. The unit starts looking for the pulse. If the trigger level is still too low or too high, the “LONG INT TRIG NOT DETECTED” message will be displayed brieﬂy. Note that it may take as long as the timeout value for the message to appear.

6. If the message appeared, repeat step 5 until a valid trigger level is found.

7. Use the MENU key to back out of the menu structure and display long integration current measurements.

4-8 Long Integration Measurements

SCPI programming

Table 4-1

SCPI commands — long integration measurements

Commands Description Default Ref

SENSe :FUNCtion “LINTegration” :LINTegration :TIME <NRf>

:AUTO :TLEVel <NRf>

:TLEVel [:AMPs] <NRf>

:MILLiamp <NRf>

:TEDGe <name>

:TimeOUT <NRf> :SEARch :FAST

SENSe subystem: Select long integration measurement function. Long integration conﬁguration: Set integration time (in sec); X to 60 (where X is

0.850 for 60Hz, or 0.840 for 50Hz). Integration time set automatically. Models 2303 and 2303B - Set trigger level in amps; 0 to 5 (5mA resolution. Model 2303-PJ trigger level: Set trigger level (in amps) for 5A range; 0 to 5 (5mA resolution). Set trigger level (in amps) for 500mA range; 0 to

0.5 (0.5mA resolution). Select trigger edge to initiate the measurement; RISING, FALLING or NEITHER. Specify length of timeout; 1 to 63 (sec). Enable or disable pulse search. Enable or disable long integrations fast readings.

VOLT

0.0

RISING

16 ON OFF

C D

READ?

Trigger and return one reading.

A. SENSe:FUNCtion ‘LINTegration’

The parameter name can instead be enclosed in single quotes (as shown above).

B. SENSe:LINTegration:TIME <NRf>

1. The time value sent is rounded down to the nearest step value, which is based on the power line frequency. For 60Hz, the step value is 16.667 msec. For 50Hz, the step value is 20msec. For example, for 50Hz, a time value of 10.025 seconds is between steps. Therefore, the integration period will round down to 10.020 seconds.

2. When there is uncertainty about the actual integration time period, use the :TIME? query command to read it.

3. The response for :TIME? is affected by the GPIB output format. For decimal formats, the response has four decimal places, otherwise it is in exponential format. See Section 6 to select the output format.

Long Integration Measurements 4-9

C. SENSe:LINTegration:SEARch

Boolean Parameters:

• OFF or 0 - The search will stop after the ﬁrst timeout period expires. The search can be restarted by enabling the search, or by sending a trigger reading command (such as READ?).

• ON or 1 - The instrument will continue to search for a pulse after the timeout period expires. Therefore, with a long timeout setting and the search enabled, the instrument may appear locked up while it is searching for the pulse to start the long integration. In addition, the time needed to execute code after timing out, and to start the pulse search, is fast compared to timeout settings. Hence, with no pulse detection and search enabled, the power supply is mostly searching for the pulse.

D. SENSe:LINTegration:FAST

Boolean Parameters:

• OFF or 0 - The instrument searches for pulses when it receives :TLEVel commands to determine if the level value will cause pulses to be detected. In addition, the unit will take background readings between user trigger commands to determine if the pulse still exists.

• ON or 1 - The unit does not search for pulses when it receives a :TLEVel command and will not take background readings between user trigger commands. Therefore, the pulse trigger timeout bit in the measurement event register is not updated unless a user trigger command is sent. Plus, the NO PULSE message will only appear after receiving a user trigger reading command. With this setting, only a user trigger reading command causes the unit to look for a pulse. Therefore, no information on pulse detection is available until a user triggered command is received.

E. READ?

After sending a trigger reading command to perform long integration measurements, do not address the power supply to talk until all readings are completed. Details on READ? and the other signal oriented measurement commands are provided in Section 9.

Programming example

The following command sequence will trigger and return one long integration measurement:

SENS:RANG 5 ‘ Select 5A range. VOLT 15 ‘ Set output voltage to 15V. CURR 0.75 ‘ Set current limit to 750mA. OUTP ON ‘ Turn output on. SENS:LINT:TIME:AUTO ‘ Set integration time automatically for

SENS:LINT:TLEV 0.1 ‘ Set trigger level to 100mA. SENS:LINT:TEDge RISING ‘ Select rising trigger edge to initiate

SENS:FUNC “LINT” ‘ Select long integration function. READ? ‘ Trigger and return one reading.

single pulse.

‘ measurement.

4-10 Long Integration Measurements

Relay Control

• Overview — Summarizes how the power supply can be used to control an external relay.

• Connections — Explains how to connect an external relay circuit to the power supply.

• Controlling the relay — Explains how to control the external relay circuit.

5-2 Relay Control

Overview

an open-collector transistor that functions as a switch for the external relay, a +5VDC source (100mADC maximum), and a chassis ground return. The drive for the relay may be provided by the supplied +5VDC source or an external DC voltage source.

ﬁguration to control an external relay. As shown in the illustration, voltage applied to the power supply must not exceed 15VDC and current for the relay circuit must not exceed 150mADC. If the supplied +5VDC source is used to drive the external relay, the relay circuit must not exceed 100mADC.

vides a current dissipation path for ﬂy-back voltage from the relay coil that occurs when the control circuit is opened. Without the diode, the high ﬂy-back voltage could damage the power supply.

CAUTION To prevent damage to the power supply that is not covered by the warranty,

The power supply can be used to control an external relay. The control circuit is made up of

Figure 5-1 shows the simpliﬁed control circuit in the power supply and shows a typical con-

Also note that a protection diode is required for the relay circuit. The protection diode pro-

adhere to the following precautions:

• ALWAYS use a protection diode for the relay circuit as shown in Figure 5-1.

• Do not exceed the voltage and current limits of the RELAY CONTROL port of the power supply (15VDC and 150mADC).

• Connect and disconnect relay drive circuits with the power supply power OFF.

NOTE The current limit can also be used to control the external relay. Refer to “Current

limit modes” in Section 2.

Figure 5-1

Relay control

Power Supply Relay Control

Relay

Chassis

Ground

Relay

Protection Diode

+5VDC

External

Source

15VDC

Max

A. External Source

Relay Control 5-3

Internal

Source

+5VDC

±5%

Relay

Chassis Ground

Relay

Protection Diode

B. Internal Source

5-4 Relay Control

Connections

An external relay circuit is connected to the power supply via the miniature phono jack on the rear panel (labeled relay control 15VDC MAX). The required phono plug that mates to the phono jack is shown in Figure 5-2. The illustration provides terminal identiﬁcation for the conductors of the plug. This phone plug is available from Switchcraft, Inc. (see table for Switchcraft connection accessories).

Also available from Switchcraft is a three-conductor patch cord that is terminated with a phono plug on each end. The patch cord is available in various lengths from 0.5 ft to 6 ft. The part numbers for the patch cords are listed in the table for Switchcraft connection accessories. You can remove (cut) one of the phono plugs from the patch cord. One end of the modiﬁed patch cord plugs into the phono jack on the power supply, and the unterminated end is hard-wired to the external relay circuit(s).

Another alternative is to wire the external relay circuit to a second phono jack. You can then use an unmodiﬁed patch cord to connect the relay circuit to the power supply. The part number for the phono jack is listed in the table for Switchcraft connection accessories.

Figure 5-2

Miniature phono plug

Relay

+5VDC

Table 5-1

Switchcraft connection accessories

Part number Description

TT253 UJ2B

TT741 TT742 TT744 TT746 TT747 TT748 TT749

Switchcraft, Inc. 5555 N. Elston Ave. Chicago, IL 60630 Phone: 312-631-1234 FAX: 312-792-2129

Miniature Phono Plug (3-conductor) Miniature Phono Jack (3-conductor)

Patch Cords (3-conductor):

0.5 ft patch cord 1 ft patch cord 2 ft patch cord 3 ft patch cord 4 ft patch cord 5 ft patch cord 6 ft patch cord

Chassis Ground

Controlling the relay

The external relay is controlled from the OUTPUT RELAY item of the menu. The menu is

accessed by pressing the MENU key.

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

1. From the menu, select OUTPUT RELAY.

2. Select the desired relay control option: ONE or ZERO. Selecting ONE closes the relay control circuit to energize the relay, while ZERO opens the circuit to de-energize the relay.

SCPI programming

Table 5-2

SCPI command — output relay control

Command Description Default

OUTPut :RELay <name>

Relay Control 5-5

OUTPut subsystem: Close (ONE) or open (ZERO) relay control circuit. ZERO

5-6 Relay Control

GPIB Operation

• Introduction — Describes the IEEE-488 (GPIB) standards used by the power supply.

• GPIB bus connections — Shows how to connect the power supply to the GPIB.

• Primary address — Explains how to check and/or change the primary address for the bus.

• Output format — Covers the output formats for readings sent over the bus, and output

types for the response to *IDN?.

• General bus commands — Documents general bus commands that pertain to all GPIB

instruments.

• Programming syntax — Provides syntax information for sending command and SCPI

commands over the bus.

6-2 GPIB Operation

WARNING:NO INTERNAL OPERATOR SERVICABLE PARTS,SERVICE BY QUALIFIED PERSONNEL ONLY.

CAUTION:FOR CONTINUED PROTECTION AGAINST FIRE HAZARD,REPLACE FUSE WITH SAME TYPE AND RATING.

Introduction

The GPIB bus is the IEEE-488 instrumentation data bus with hardware and programming

standards originally adopted by the IEEE (Institute of Electrical and Electronic Engineers) in

1975. The power supply conforms to these standards:

• IEEE-488-1987.1

• IEEE-488-1987.2

These standards deﬁne a syntax for sending data to and from instruments, how the instrument interprets this data, what registers should exist to record the state of the instrument, and a group of common commands.

• SCPI 1995.0 (Standard Commands for Programmable Instruments)

This standard deﬁnes a command language protocol. It goes one step further than IEEE-488-

1987.2 and deﬁnes a standard set of commands to control every programmable aspect of the instrument.

GPIB bus connections

To connect the power supply to the GPIB bus, use a cable equipped with standard IEEE-488 connectors. The IEEE connector on the power supply is shown in Figure 6-1.

Figure 6-1

IEEE-488 connector

LINE FUSE

DVM IN

SLOWBLOW

2.0A, 250V

LINE RATING

100-120VAC/ 200-240VAC

50, 60 HZ

150VA MAX

RELAY

CONTROL

15VDC MAX

REMOTE DISPLAY

OPTION

MADE IN

U.S.A.

ISOLATION FROM EARTH:

22 VOLTS MAX.

____

+++

SOURCE SENSE

SOURCE

OUTPUT

15V/3A 9V/5A

IEEE-488

(CHANGE IEEE ADDRESS

WITH FRONT PANEL MENU)

IEEE-488 Connector

NOTE To minimize interference caused by electromagnetic radiation, use only shielded IEEE-

488 cables. Available shielded cables from Keithley are Models 7007-1 and 7007-2.

For a multi-unit test system, you can daisy-chain the instruments to the controller by connecting an IEEE cable from one unit to another.

Most controllers are equipped with an IEEE-488 style connector, but a few may require a different type of connecting cable. See the controller’s instruction manual if it is not equipped with an IEEE-488 style connector.

Primary address

The power supply ships from the factory with a GPIB address of 16. You can set the address to a value of 0 to 30. Do not assign the same address to another device or to a controller that is on the same GPIB bus.

The GPIB address is checked and/or changed from the menu (which is accessed by pressing the MENU key).

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

Once in the menu, select GPIB menu and then select ADDRESS. After setting the address value, make sure you press ENTER to select it.

NOTE The present address is displayed on power-up on the top line of the display.

Output format

Readings over the bus can be returned in the exponential or decimal format. For the exponential format, a +10V reading would be returned as +1.00000000E+01. For a decimal format, it would be returned as 10.00 (2 decimal places), 10.000 (3 decimal places) or 10.0000 (4 decimal places).

GPIB Operation 6-3

The output type (KEITHLEY or FLUKE) can be set for the response to the *IDN? query command. *IDN? provides identiﬁcation information. See Section 8 for details on the responses for *IDN?

The output format and type is selected from the menu (which is accessed by pressing the MENU key).

NOTE Table 1-2 (in Section 1) shows the menu structure. Rules to navigate the menu follow

the table.

Once in the menu select GPIB MENU and then select OUTPUT FORMAT. Both format and type is selected from this secondary menu item.

Format - Using the DECIMAL PLACES, 3 DECIMAL PLACES, or 4 DECIMAL PLACES), and press ENTER.

Type - To select the format type for *IDN?, use the FLUKE, and press ENTER.

NOTE Output format and type are retained through a power cycle and are not affected by

*RST or *RCL.

 and  keys, display the desired output format (EXPONENTIAL, 2

 or  key to display KEITHLEY or

6-4 GPIB Operation

General bus commands

General bus commands are those commands, such as DCL, that have the same general mean-

ing regardless of the instrument. Table 6-1 lists the general bus commands.

Table 6-1

General bus commands

Command Effect on power supply

REN IFC LLO GTL DCL SDC GET SPE, SPD

REN (remote enable)

Goes into remote when next addressed to listen. Reset interface; all devices go into talker and listener idle states. Local key locked out. Cancel remote; restore front panel operation for the power supply. Return all devices to known conditions. Returns power supply to known conditions. Initiates a trigger. Serial polls the power supply.

The remote enable command is sent to the power supply by the controller to set up the instrument for remote operation. Generally, the instrument should be placed in the remote mode before you attempt to program it over the bus. Simply setting REN true does not actually place the instrument in the remote state. You must address the instrument to listen after setting REN true before it goes into remote.

Note that the instrument does not have to be in remote to be a talker.

Also, note that all front panel controls except for LOCAL and POWER are inoperative while the instrument is in remote. You can restore normal front panel operation by pressing the LOCAL key.

IFC (interface clear)

The IFC command is sent by the controller to place all instruments on the bus in the local, talker, listener idle states. The power supply responds to the IFC command by canceling front panel TALK or LSTN lights, if the instrument was previously placed in one of those states. Note that this command does not affect the status of the instrument; settings, data, and event registers are not changed.

To send the IFC command, the controller must set the IFC line true for a minimum of 100µs.

LLO (local lockout)

Use the LLO command to prevent local operation of the instrument. After the unit receives LLO, all its front panel controls except POWER are inoperative. In this state, pressing the LOCAL key will not restore control to the front panel. The GTL command restores control to the front panel.

GTL (go to local)

Use the GTL command to put a remote mode instrument into local mode. The GTL command also restores front panel key operation.

DCL (device clear)

Use the DCL command to clear the GPIB interface and return it to a known state. Note that the DCL command is not an addressed command, so all instruments equipped to implement DCL will do so simultaneously.

When the power supply receives a DCL command, it clears the input buffer and output queue, cancels deferred commands, and clears any command that prevents the processing of any other device command. A DCL does not affect instrument settings and stored data.

GPIB Operation 6-5

SDC (selective device clear)

The SDC command is an addressed command that performs essentially the same function as the DCL command. However, since each device must be individually addressed, the SDC command provides a method to clear only selected instruments instead of clearing all instruments simultaneously, as is the case with DCL.

GET (group execute trigger)

GET is a GPIB trigger that is used as an event to control operation. The power supply reacts to this trigger if it is the programmed control source. The control source is programmed from the SCPI TRIGger subsystem.

SPE, SPD (serial polling)

Use the serial polling sequence to obtain the power supply serial poll byte. The serial poll byte contains important information about internal functions. Generally, the serial polling sequence is used by the controller to determine which of several instruments has requested service with the SRQ line. However, the serial polling sequence may be performed at any time to obtain the status byte from the power supply.

6-6 GPIB Operation

Front panel aspects of GPIB operation

The following paragraphs describe aspects of the front panel and remote panel that are part

of GPIB operation, including the remote operation indicator, LOCAL key, and messages.

Remote indicator and LOCAL key

When the power supply is in the remote state, the “R” character is displayed in the bottom right corner of the display. It blinks as a solid block character. “R” does not necessarily indicate the state of the REM line, as the instrument must be addressed to listen with REM true before the “R” indicator turns on.

When the instrument is in remote, all front panel keys, except for the LOCAL key, are locked out. The LOCAL key cancels the remote state and restores local operation of the instrument. Pressing the LOCAL key also turns off the “R” indicator and returns the display to normal if a user-deﬁned message was displayed.

If the LLO (local lockout) command is in effect, the LOCAL key is also inoperative.

Error and status messages

See Appendix B for a list of error and status messages associated with IEEE-488 programming. The instrument can be programmed to generate an SRQ, and command queries can be performed to check for speciﬁc error conditions.

Programming syntax

The information in the following paragraphs covers syntax for both common commands and

SCPI commands. For information not covered here, see the IEEE-488.2 and SCPI standards.

Command words

Program messages are made up of one or more command words and parameters.

Commands and command parameters

Common commands and SCPI commands may or may not use a parameter. The following

are some examples:

*SAV <NRf> Parameter (NRf) required *RST No parameter used :DISPlay:TEXT:STATe Parameter required :STATus:PRESet No parameter used.

Put at least one space between the command word and the parameter.

Brackets [ ] — Some command words are enclosed in brackets ([]). These brackets are used

to denote an optional command word that does not need to be included in the program message. For example:

GPIB Operation 6-7

:FORMat[:DATA]?

These brackets indicate that :DATA is implied (optional) and does not have to be used. Thus,

the above command can be sent as :FORMat? or :FORMat:DATA?.

Notice that the optional command is used without the brackets. When using optional com-

mand words in your program, do not include the brackets.

Parameter types — The following are some of the more common parameter types:

• Boolean — Used to enable or disable an instrument operation. 0 or OFF disables the operation, and 1 or ON enables the operation. Example:

:DISPlay:TEXT:STATe ON Enable text message mode of display.

• <name> Name parameter — Select a parameter name from a listed group. Example:

<name> = LIMit

= TRIP

:CURRent:LIMit:TYPE TRIP Turn output off when current limit reached.

6-8 GPIB Operation

• <NRf> Numeric representation format — This parameter is a number that can be

• <n> Numeric value — A numeric value parameter can consist of an NRf number or one

• <numlist> Numlist — Specify one or more numbers for a list. Example:

Angle Brackets < > — Angle brackets (< >) are used to denote a parameter type. Do not in-

clude the brackets in the program message. For example:

expressed as an integer (e.g., 8), a real number (e.g., 23.6), or an exponent (2.3E6). Example:

SENSe:AVERage 5 Set average count value to 5

of the following name parameters: DEFault, MINimum, MAXimum. When the DEFault parameter is used, the instrument is programmed to the *RST default value. When the MINimum parameter is used, the instrument is programmed to the lowest allowable value. When the MAXimum parameter is used, the instrument is programmed to the largest allowable value. Examples:

:SENSe:NPLCycles 2 Set integration period to 2 PLC :SENSe:NPLCycles DEFault Set integration period to 1 PLC :SENSe:NPLCycles MINimum Set integration period to 0.01 PLC :SENSe:NPLCycles MAXimum Set integration period to 10 PLC

:STATus:QUEue:ENABle (-110:-222) Enable errors -110 thru -222

:OUTPut

The indicates that a Boolean-type parameter is required. Therefore, to turn on the output,

the command with the ON or 1 parameter must be sent as follows.

:OUTPut ON :OUTPut 1

Query commands

This type of command requests (queries) the presently programmed status. It is identiﬁed by the question mark (?) at the end of the fundamental form of the command. Most commands have a query form. Example:

:SENSe:CURRent:RANGe? Queries the present current range.

Most commands that require a numeric parameter (<n>) can also use the DEFault, MINimum, and MAXimum parameters for the query form. These query forms are used to determine the *RST default value and the upper and lower limits for the fundamental command. Examples:

:SENSe:CURRent:RANGe? DEFault Queries the *RST default value.

:SENSe:CURRent:RANGe? MINimum Queries the lowest allowable value.

:SENSe:CURRent:RANGe? MAXimum Queries the largest allowable value.

GPIB Operation 6-9

Case sensitivity

Common commands and SCPI commands are not case sensitive. You can use upper or lower

case and any case combination. Examples:

*RST = *rst :DATA? = :data? :STATus:PRESet = :status:preset

Long-form and short-form versions

A SCPI command word can be sent in its long-form or short-form version. The command subsystem tables in Section 4 provide the long-form version. However, the short-form version is indicated by upper case characters. Examples:

:STATus:PRESet long-form

:STAT:PRES short-form

:STATus:PRES long-form and short-form combination

Note that each command word must be in either long-form or short-form. For example,

:STATu:PRESe is illegal and will generate an error. The command will not be executed.

Short-form rules

Use the following rules to determine the short-form version of any SCPI command or parameter:

• If the length of the word is four letters or less, no short form version exists. Example: :auto = :auto

These rules apply to words that exceed four letters:

• If the fourth letter of the word is a vowel, delete it and all the letters after it. Example: :dvmeter = :dvm

• If the fourth letter of the command word is a consonant, retain it but drop all the letters after it. Example: :format = :form

• If the command contains a question mark (?; query) or a non-optional number included in the command word, you must include it in the short-form version. Example: :function? = :func?

• Command words or characters that are enclosed in brackets ([]) are optional and need not be included in the program message.

6-10 GPIB Operation

Program messages

A program message is made up of one or more command words sent by the computer to the instrument. Each common command is a three letter acronym preceded by an asterisk (*). SCPI commands are categorized in the :STATus subsystem and are used to help explain how command words are structured to formulate program messages.

:STATus Path (Root)

:OPERation Path

:PRESet Command

Single command messages

The previous command structure has three levels. The ﬁrst level is made up of the root command (:STATus) and serves as a path. The second level is made up of another path (:OPERation) and a command (:PRESet). The third path is made up of one command for the :OPERation path. The three commands in this structure can be executed by sending three separate program messages as follows:

:stat:oper:enab <NRf>

:stat:oper:enab?

:stat:pres

In each of the above program messages, the path pointer starts at the root command (:stat) and moves down the command levels until the command is executed.

:ENABle <NRf> Command and parameter :ENABle? Query command

Multiple command messages

You can send multiple command messages in the same program message as long as they are separated by semicolons (;). Here is an example showing two commands in one program message:

:stat:pres; :stat:oper:enab <NRf>

When this command is sent, the ﬁrst command word is recognized as the root command (:stat). When the next colon is detected, the path pointer moves down to the next command level and executes the command. When the path pointer sees the colon after the semicolon (;), it resets back to the root level and starts over.

Commands that are on the same command level can be executed without having to retype the entire command path. Example:

:stat:oper:enab <NRf>; enab?

After the ﬁrst command (:enab) is executed, the path pointer is at the third command level in the structure. Since :enab? is also on the third level, it can be typed in without repeating the entire path name. Notice that the leading colon for :enab? is not included in the program message. If a colon were included, the path pointer would reset to the root level and expect a root command. Since :enab? is not a root command, an error would occur.

GPIB Operation 6-11

Command path rules

• Each new program message must begin with the root command, unless it is optional (e.g., [:SOURce]). If the root is optional, treat a command word on the next level as the root.

• The colon (:) at the beginning of a program message is optional and need not be used. Example:

:stat:pres = stat:pres

• When the path pointer detects a colon (:), it moves down to the next command level. An exception is when the path pointer detects a semicolon (;), which is used to separate commands within the program message (see next rule).

• When the path pointer detects a colon (:) that immediately follows a semicolon (;), it resets back to the root level.

• The path pointer can only move down; it cannot be moved up a level. Executing a command at a higher level requires that you start over at the root command.

Using common and SCPI commands in the same message

Both common commands and SCPI commands can be used in the same message as long as they are separated by semicolons (;). A common command can be executed at any command level and will not affect the path pointer. Example:

:stat:oper:enab <NRf>; *ESE <NRf>

Program message terminator (PMT)

Each program message must be terminated with an LF (line feed), EOI (end or identify), or an LF+EOI. The bus will hang if your computer does not provide this termination. The following example shows how a program message must be terminated:

:outp on <PMT>

Command execution rules

• Commands execute in the order that they are presented in the program message.

• An invalid command generates an error and is not executed.

• Valid commands that precede an invalid command in a multiple command program message are executed.

• Valid commands that follow an invalid command in a multiple command program message are ignored.

6-12 GPIB Operation

Response messages

A response message is the message sent by the instrument to the computer in response to a

query command program message.

Sending a response message

After sending a query command, the response message is placed in the output queue. When the power supply is then addressed to talk, the response message is sent from the output queue to the computer.

Multiple response messages

If you send more than one query command in the same program message (see “Multiple command messages”), the multiple response messages for all the queries are sent to the computer when the power supply is addressed to talk. The responses are sent in the order the query commands were sent and are separated by semicolons (;). Items within the same query are separated by commas (,). The following example shows the response message for a program message that contains four single item query commands:

0; 1; 1; 0

Response message terminator (RMT)

Each response is terminated with an LF (line feed) and EOI (end or identify). The following example shows how a multiple response message is terminated:

0; 1; 1; 0; <RMT>

Message exchange protocol

Two rules summarize the message exchange protocol:

Rule 1: You must always tell the power supply what to send to the computer.

The following two steps must always be performed to send information from the instrument to the computer:

1. Send the appropriate query command(s) in a program message.

2. Address the power supply to talk.

Rule 2: The complete response message must be received by the computer before another

program message can be sent to the power supply.

Status Structure

• Overview — Provides an operational overview of the status structure for the power

supply.

• Clearing registers and queues — Covers the actions that clear (reset) registers and

queues.

• Programming and reading registers — Explains how to program enable registers and

read any register in the status structure.

• Status byte and service request (SRQ) — Explains how to program the status byte to

generate service requests (SRQs). Shows how to use the serial poll sequence to detect SRQs.

• Status register sets — Provides bit identiﬁcation and command information for the four

status register sets; standard event status, operation event status, measurement event status and questionable event status.

• Queues — Provides details and command information on the output queue and error

queue.

7-2 Status Structure

Overview

The power supply provides a series of status registers and queues allowing the operator to monitor and manipulate the various instrument events. The status structure is shown in Figure 7-1. The heart of the status structure is the status byte register. This register can be read by the users test program to determine if a service request (SRQ) has occurred, and what event caused it.

Status byte and SRQ

The status byte register receives the summary bits of four status register sets and two queues. The register sets and queues monitor the various instrument events. When an enabled event occurs, it sets a summary bit in the status byte register. When a summary bit of the status byte is set and its corresponding enable bit is set (as programmed by the user), the RQS/MSS bit will set to indicate that an SRQ has occurred.

Status register sets

A typical status register set is made up of a condition register, an event register and an event enable register. A condition register is a read-only register that constantly updates to reﬂect the present operating conditions of the instrument.

Queues

When an event occurs, the appropriate event register bit sets to 1. The bit remains latched to 1 until the register is reset. When an event register bit is set and its corresponding enable bit is set (as programmed by the user), the output (summary) of the register will set to 1, which in turn sets the summary bit of the status byte register.

The power supply uses an output queue and an error queue. The response messages to query commands are placed in the output queue. As various programming errors and status messages occur, they are placed in the error queue. When a queue contains data, it sets the appropriate summary bit of the status byte register.

Figure 7-1

Status model structure

Status Structure 7-3

Calibration Summary

(Always Zero)

Operation Complete

Query Error

Device Specific Error

Execution Error

Command Error

User Request

Power On

(Always Zero)

Measurement Event Registers

Condition

Buffer Full

ROF

RAV

BF 10 11 12 13 14 15

:CONDition?

Reading Overflow

Pulse Trigger Timeout PTT

Reading Available

(Always Zero)

Questionable Event Registers

Condition

Cal

10 11 12 13

:CONDition? [:EVENt]? :ENABle <NRf>

Event

0 1 2 3 4 5 6 7

Cal

9 10 11 12 13

Output Queue

Standard Event Registers

Event

Event Enable

OPC

QYE DDE EXE

CME URQ PON

*ESR?

0 1 2

6 7 8

OPC

QYE

DDE

EXE

CME

URQ

PON

9 10 11 12 13 14 14 15

Event

ROF

PTT

RAV

BF 10 11 12 13 14 15

[:EVENt]?

1 2

6 7 8

*ESE <NRf>

*ESE?

:ENABle <NRf>

:ENABle?

Event

Enable

1 2

ROF

PTT

RAV

6 7

8 BF 10 11 12 13 14 15

Event

Enable

0 1

3 4 5 6

Cal

9 10 11 12 13 14 15

:ENABle?

Logical

Current Limit

Current Limit Tripped

Power Supply Shutdown

(Always Zero)

Error Queue

Service

Status

Byte

MSB MSB

1 EAV QSB MAV ESB

RQS/MSS

OSB

*STB?

Request

Enable

EAV QSB

MAV

ESB

OSB

*SRE *SRE?

Logical

Master Summary Status (MSS)

MSB = Measurement Summary Bit EAV = Error Available QSB = Questionable Summary Bit MAV = Message Available ESB = Event Summary Bit RQS/MSS = Request for Service/Master Summary Staus OSB = Operation Summary Bit

Note : RQS bit is in serial poll byte, MSS bit is in *STB? response.

Operation Event Registers

0 1 2

7 8 9

Event Enable Register

CLT

PSS

:ENABle <NRf>

:ENABle?

Condition

0 1 2

CLT

PSS

7 8 9

11 12 13 14 15

:CONDition? [:EVENt]?

Event

CLT

PSS

10 11 12 13 14 15

Logical

7-4 Status Structure

Clearing registers and queues

When the power supply is turned on, the bits of all registers in the status structure are clear (reset to 0) and the two queues are empty. Commands to reset the event and event enable registers, and the error queue are listed in Table 7-1. In addition to these commands, any enable register can be reset by sending the 0 parameter value with the individual command to program the register.

NOTE *RST has no effect on status structure registers and queues. See “Queues” for details

on the error queue.

Table 7-1

Common and SCPI commands — reset registers and clear queues

Commands Description Ref

To reset registers: *CLS

Reset all bits of the following event registers to 0: Standard event register Operation event register Measurement event register Questionable event register

STATus

:PRESet

To clear error queue: *CLS

STATus

:QUEue

{:NEXT}? :CLEar

SYSTem

:ERRor? :CLEar

Notes:

1. The standard event enable register is not reset by STATus:PRESet or *CLS. Send the 0 parameter value with *ESE to reset all bits of that enable register to 0 (see “Status byte and service request commands”).

2. STATus:PRESet has no effect on the error queue.

3. Use either of the two :CLEar commands to clear the error queue.

STATus subsystem: Reset all bits of the following enable registers to 0: Operation event enable register Measurement event enable register Questionable event enable register

Clear all messages from error queue Note 2

STATus subsystem:

Error queue:

Read and clear the oldest error/status message. Clear all messages from error queue.

SYSTem subsystem:

Read and clear the oldest error/status message. Clear all messages from error queue.

Note 1

Note 3

Programming and reading registers

Programming enable registers

The only registers that can be programmed by the user are the enable registers. All other registers in the status structure are read-only registers. The following explains how to ascertain the parameter value for the various commands used to program enable registers. The actual commands are covered later in this section (see Tables 7-2 and 7-5).

A command to program an event enable register is sent with a decimal parameter value that determines the desired state (0 or 1) of each bit in the appropriate register. The bit positions of the register (see Figure 7-2) indicate the parameter value in binary format. For example, if you wish to sets bits B4, B3 and B1, the binary value would be 11010 (where B4=1, B3=1, B2=0, B1=1, B0=0 and all other bits are 0). The decimal equivalent of binary 11010 is 26. Therefore, the parameter value for the enable command is 26.

Another way to determine the decimal value is to add up the decimal weights for the bits that you wish to set. Note that Figure 7-2 includes the decimal weight for each register bit. To set bits B4, B3 and B1, the parameter value would be the sum of the decimal weights for those bits (16+8+2 = 26).

Status Structure 7-5

Figure 7-2

16-bit status register

A) Bits 0 through 7

Bit Position B7 B6 B5 B4 B3 B2 B1 B0

Binary Value 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1

Decimal Weights

B) Bits 8 through 15

Bit Position B15 B14 B13 B12 B11 B10 B9 B8

Binary Value 0/1 0/1 0/1 0/1 0/1 0/1 0/1 0/1

Decimal Weights

Reading registers

Any register in the status structure can be read by using the appropriate query (?) command. The speciﬁc query commands are covered later in this section (see Tables 7-2 through 7-5).

The response message to the query command is a decimal value. To determine which bits in the register are set, convert that decimal value to its binary equivalent. For example, the binary equivalent of decimal 41 is 101001. This binary value indicates that bits B5, B3 and B0 are set.

128

)

32768

)

16384

32 (2

8192 (2

)

4096

)

2048

)

1024

)

512

)

256 (2

)

7-6 Status Structure

Status byte and service request (SRQ)

Service request is controlled by two 8-bit registers; the status byte register and the service

request enable register. Figure 7-3 shows the structure of these registers.

Figure 7-3

Status byte and service request

Status Summary Messages (6)

Service

Request

Generation

* STB?

Serial Poll

* SRE

* SRE?

Decimal

Weights

RQS

ESB

MAV

OSB

(B6)

(B7)

OSB (B7) (B6)

128

)

OSB = Operation Summary Bit MSS = Master Summary Status RQS = Request for Service ESB = Event Summary Bit MAV = Message Available QSB = Questionable Summary Bit EAV = Error Available MSB = Measurement Summary Bit & = Logical AND OR = Logical OR

(B5)

MSS

ESB (B5)

(25)16(24)8(23)4(22)

(B4)

MAV (B4)

QSB

(B3)

QSB (B3)

EAV (B2)

(B1)

MSB

(B0)

MSB

(B0)

)

Status Byte Register

Service Request Enable Register

Status byte register

The summary messages from the status registers and queues are used to set or clear the appropriate bits (B0, B2, B3, B4, B5, and B7) of the status byte register. These summary bits do not latch, and their states (0 or 1) are solely dependent on the summary messages (0 or 1). For example, if the standard event register is read, its register will clear. As a result, its summary message will reset to 0, which in turn will reset the ESB bit in the status byte register.

The bits of the status byte register are described as follows:

• Bit B0, measurement status (MSB) — Set summary bit indicates that an enabled mea-

surement event has occurred.

• Bit B1 — Not used.

• Bit B2, error available (EAV) — Set summary bit indicates that an error or status mes-

sage is present in the error queue.

• Bit B3, questionable summary bit (QSB) — Set summary bit indicates that an enabled

questionable event has occurred.

• Bit B4, message available (MAV) — Set summary bit indicates that a response message

is present in the output queue.

• Bit B5, event summary bit (ESB) — Set summary bit indicates that an enabled stan-

dard event has occurred.

• Bit B6, request service (rqs)/master summary status (MSS) — Set bit indicates that

an enabled summary bit of the status byte register is set.

• Bit B7, operation summary (OSB) — Set summary bit indicates that an enabled oper-

ation event has occurred.

Status Structure 7-7

Depending on how it is used, Bit B6 of the status byte register is either the request for service (RQS) bit or the master summary status (MSS) bit:

• When using the serial poll sequence of the power supply to obtain the status byte (a.k.a. serial poll byte), B6 is the RQS bit. See “Serial Polling and SRQ” for details on using the serial poll sequence.

• When using the *STB? command (see Table 7-3) to read the status byte, B6 is the MSS bit.

Service request enable register

The generation of a service request is controlled by the service request enable register. This register is programmed by the user and is used to enable or disable the setting of bit B6 (RQS/ MSS) by the status summary message bits (B0, B2, B3, B4, B5, and B7) of the status byte register. As shown in Figure 7-3, the summary bits are logically ANDed (&) with the corresponding enable bits of the service request enable register. When a set (1) summary bit is ANDed with an enabled (1) bit of the enable register, the logic “1” output is applied to the input of the OR gate and, therefore, sets the MSS/RQS bit in the status byte register.

7-8 Status Structure

The individual bits of the service request enable register can be set or cleared by using the *SRE common command. To read the service request enable register, use the *SRE? query command. The service request enable register clears when power is cycled or a parameter value of 0 is sent with the *SRE command (i.e. *SRE 0). The commands to program and read the SRQ enable register are listed in Table 7-2.

Serial polling and SRQ

Any enabled event summary bit that goes from 0 to 1 will set bit B6 and generate an SRQ (service request). In your test program, you can periodically read the status byte to check if an SRQ has occurred and what caused it. If an SRQ occurs, the program can, for example, branch to an appropriate subroutine that will service the request.

Typically, SRQs are managed by the serial poll sequence of the power supply. If an SRQ does not occur, bit B6 (RQS) of the status byte register will remain cleared, and the program will simply proceed normally after the serial poll is performed. If an SRQ does occur, bit B6 of the status byte register will set, and the program can branch to a service subroutine when the SRQ is detected by the serial poll.

The serial poll automatically resets RQS of the status byte register. This allows subsequent serial polls to monitor bit B6 for an SRQ occurrence generated by other event types. After a serial poll, the same event can cause another SRQ, even if the event register that caused the ﬁrst SRQ has not been cleared.

The serial poll does not clear MSS. The MSS bit stays set until all status byte summary bits are reset.

SPE, SPD (serial polling)

The SPE, SPD general bus command is used to serial poll the power supply. Serial polling obtains the serial poll byte (status byte). Typically, serial polling is used by the controller to determine which of several instruments has requested service with the SRQ line.

Status byte and service request commands

The commands to program and read the status byte register and service request enable register are listed in Table 7-2. For details on programming and reading registers, see “Programming enable registers” and “Reading registers”.

NOTE To reset the bits of the service request enable register to 0, use 0 as the parameter

value for the *SRE command (i.e. *SRE 0).

Table 7-2

Command commands — status byte and service request enable registers

Command Description Default

Status Structure 7-9

*STB? *SRE <NRf> *SRE?

Note: *CLS and STATus:PRESet have no effect on the service request enable register.

Read status byte register. Program the service request enable register: 0 to 255 Read the service request enable register

(Note)

Programming example — read status byte

The following command sequence enables EAV (error available), sends an invalid command, and then reads the status byte register:

*CLS ‘ Clear Status Byte Register. *SRE 4 ‘ Enable EAV. BAD:COMMand ‘ Send an invalid command to generate an error. *STB? ‘ Read status byte. The value 68 will be returned to indicate

that bits B2 (EAV) and B6 (MSS) of the Status Byte Register are set.

7-10 Status Structure

Status register sets

As shown in Figure 7-1, there are four status register sets in the status structure of the power supply: standard event status, operation event status, measurement event status and questionable event status.

Standard event status

The used bits of the standard event register (shown in Figure 7-4) are described as follows:

• Bit B0, operation complete — Set bit indicates that all pending selected device opera-

tions are completed and the power supply is ready to accept new commands. This bit only sets in response to the *OPC command. See Section 8 for details on *OPC.

• Bit B2, query error (QYE) — Set bit indicates that you attempted to read data from an

empty output queue.

• Bit B3, device-dependent error (DDE) — Set bit indicates that an instrument operation

did not execute properly due to some internal condition.

• Bit B4, execution error (EXE) — Set bit indicates that the power supply detected an

error while trying to execute a command.

• Bit B5, command error (CME) — Set bit indicates that a command error has

occurred. Command errors include: → IEEE-488.2 syntax error — power supply received a message that does not follow

the deﬁned syntax of the IEEE-488.2 standard.

→ Semantic error — power supply received a command that was misspelled or

received an optional IEEE-488.2 command that is not implemented.

→ The instrument received a group execute trigger (GET) inside a program message.

• Bit B6, user request (URQ) — Set bit indicates that the LOCAL key on the power sup-

ply front panel was pressed.

• Bit B7, power ON (PON) — Set bit indicates that the power supply has been turned off

and turned back on since the last time this register has been read.

Figure 7-4

Standard event status

Status Structure 7-11

To ESB bit of Status Byte Register

*ESR?

*ESE <NRf>

*ESE?

Decimal

Weights

(B15 - B8)

PON = Power On URQ = User Request CME = Command Error EXE = Execution Error DDE = Device-Dependent Error QYE = Query Error OPC = Operation Complete

PON

(B7)

PON

(B7)

128 (2

CME

URQ

(B5)

(B6)

CME

URQ

(B5)

(B6)

)

(25)16(24)8(23)4(22)

)

EXE

DDE

(B4)

(B3)

EXE

DDE

(B4)

(B3)

& = Logical AND OR = Logical OR

QYE

(B2)

QYE

(B2)

(B1)

OPC

(B0)

OPC

(B0)

)

Standard Event Register

Standard Event Enable Register

7-12 Status Structure

Operation event status

The used bits of the operation event register (shown in Figure 7-5) are described as follows:

• Bit B3, current limit (CL) — Set bit indicates that the output is in current limit. This

• Bit B4, current limit tripped (CLT) — Set bit indicates that the output has turned off

• Bit B6, power supply shutdown (PSS) — This bit indicates that the output has turned

Figure 7-5

Operation event status

bit clears when the instrument is no longer in current limit.

due to a current limit condition. This bit clears when the output is turned back on.

off due to an overload and/or overheat condition. This typically indicates that the user tried to exceed the power output capability of the unit.

To OPC bit of Status Byte Register

:ENABle <NRf> :ENABle?

Decimal Weights

:CONDition?

[:EVENt]?

___

(B15-B7)

___

(B15-B7)

___

(B15-B7)

___

PSS = Power Supply Shutdown CLT = Current Limit Tripped CL = Current Limit

PSS

(B6)

PSS

(B6)

PSS

(B6)

___

(B5)

___

(B5)

___

(B5)

___

)

CLT (B4)

CLT

(B4)

)

(B3)

)

& = Logical AND OR = Logical OR

___

(B2-B0)

___

(B2-B0)

___

(B2-B0)

___

Operation Condition

Operation Event Register

Operation Event

Enable Register

Measurement event status

The used bits of the measurement event register (shown in Figure 7-6) are described as

follows:

• Bit B3, reading overﬂow (ROF) — Set bit indicates that voltage or current reading

• Bit B4, pulse trigger timeout (PTT) — Set bit indicates that a current pulse has

• Bit B5, reading available (RAV) — Set bit indicates that a reading was taken and

• Bit B9, buffer full (BF) — Set bit indicates that the speciﬁed number of readings

Figure 7-6

Measurement event status

Status Structure 7-13

exceeds the measurement range of the instrument.

not been detected.

processed.

(average count) have been taken.

To MSB bit of Status Byte Register

:ENABle <NRf> :ENABle?

Decimal Weights

:CONDition?

[:EVENt]?

___

(B15-B10)

___

(B15-B10)

___

(B15-B10)

___

BF = Buffer Full RAV = Reading Available

PTT = Pulse Trigger Timeout ROF = Reading Overflow

(B9)

512 (2

)

___

(B8-B6)

___

(B8-B6)

___

(B8-B6)

___

RAV (B5)

)

& = Logical AND

OR = Logical OR

PTT (B4)

ROF

(B3)

ROF

(B3)

ROF

(B3)

)

___

(B2-B0)

___

(B2-B0)

___

(B2-B0)

___

Measurement Condition Register

Measurement Event Register

Measurement Event Enable Register

7-14 Status Structure

Questionable event status

The used bit of the questionable event register (shown in Figure 7-7) is described as follows:

• Bit B8, calibration summary (Cal) — Set bit indicates that an invalid calibration con-

Figure 7-7

Questionable event status

stant was detected during the power-up sequence. This error will clear after successful calibration of the power supply.

To QSB bit of Status Byte Register

:ENABLe <NRf>

:CONDition?

[:EVENt]?

:ENABLe?

Decimal

Weights

(B15-B9)

Cal = Calibration Summary & = Logical AND

Cal

(B8)

(B7-B0)

Cal

(B8) (B7-B0)

Cal

(B8) (B7-B0)

256

)

Questionable Condition Register

Questionable Event Register

Qusetionable Event Enable Register

OR = Logical OR

Condition registers

As Figure 7-1 shows, each status register set (except the standard event register set) has a condition register. A condition register is a real-time, read-only register that constantly updates to reﬂect the present operating conditions of the instrument. For example, when a current pulse is not detected, bit B4 (PTT) of the measurement condition register will be set (1). When the pulse is detected, the bit clears (0).

The commands to read the condition registers are listed in Table 7-3. For details on reading registers, see “Reading registers”.

Table 7-3

Common and SCPI commands — condition registers

Command Description

Status Structure 7-15

STATus

:OPERation:CONDition? :MEASurement:CONDition? :QUEStionable:CONDition?

Event registers

As Figure 7-1 shows, each status register set has an event register. When an event occurs, the appropriate event register bit sets to 1. The bit remains latched to 1 until the register is reset. Reading an event register clears the bits of that register. *CLS resets all four event registers.

The commands to read the event registers are listed in Table 7-4. For details on reading registers, see “Reading registers”.

Table 7-4

Common and SCPI commands — event registers

Command Description Default

*ESR? Read standard event status register.

STATus

:OPERation:[:EVENt]? :MEASurement:[:EVENt]? :QUEStionable:[:EVENt]?

STATus subsystem:

Read operation condition register. Read measurement condition register. Read questionable condition register.

(Note)

STATus subsystem:

Read operation event register. Read measurement event register. Read questionable event register.

Note: Power-up and *CLS resets all bits of all event registers to 0. STATus:PRESet has no effect.

7-16 Status Structure

Event enable registers

As Figure 7-1 shows, each status register set has an enable register. Each event register bit is logically ANDed (&) to a corresponding enable bit of an enable register. Therefore, when an event bit is set and the corresponding enable bit is set (as programmed by the user), the output (summary) of the register will set to 1, which in turn sets the summary bit of the status byte register.

The commands to program and read the event enable registers are listed in Table 7-5. For details on programming and reading registers, see “Programming enable registers” and “Reading registers”.

NOTE The bits of any enable register can be reset to 0 by sending the 0 parameter value

with the appropriate enable command (i.e. STATus:OPERation:ENABle 0).

Table 7-5

Common and SCPI commands — event enable registers

Command Description Default

*ESE <NRf> *ESE?

Program standard event enable register (see “Parameters”). Read standard event enable register.

(Note)

STATus :OPERation :ENABle <NRf> :ENABle? :MEASurement :ENABle <NRf> :ENABle? :QUEStionable :ENABle <NRf> :ENABle?

Parameters:

<NRf> = 0 to 1023 Decimal format

Note: Power-up and STATus:PRESet resets all bits of all enable registers to 0. *CLS has no effect.

STATus subsystem: Operation event enable register: Program enable register (see “Parameters”). Read enable register. Measurement event enable register: Program enable register (see “Parameters”). Read enable register. Questionable event enable register: Program enable register (see “Parameters”). Read enable register:

Programming example — program and read measurement event register

Queues

Output queue

Status Structure 7-17

The following command sequence enables the buffer full bit (B9) of the measurement register set, and then reads the event register. After the programmed number of readings (average count) have been taken, reading the event register will return a value of 512.

STAT:MEAS:ENAB 512 ‘ Enable BF (Buffer Full).

STAT:MEAS? ‘ Read Measurement Event Register.

The power supply uses two queues, which are ﬁrst-in, ﬁrst-out (FIFO) registers:

• Output queue — Used to hold reading and response messages.

• Error Queue — Used to hold error and status messages.

The power supply status model (Figure 7-1) shows how the two queues are structured with the other registers.

The output queue holds data that pertains to the normal operation of the instrument. For example, when a query command is sent, the response message is placed in the output queue.

When data is placed in the output queue, the message available (MAV) bit in the status byte register sets. A data message is cleared from the output queue when it is read. The output queue is considered cleared when it is empty. An empty output queue clears the MAV bit in the status byte register.

A message is read from the output queue by addressing the power supply to talk after the appropriate query is sent.

7-18 Status Structure

Error queue

The error queue holds error and status messages. When an error or status event occurs, a mes-

sage that deﬁnes the error/status is placed in the error queue.

When a message is placed in the error queue, the error available (EAV) bit in the status byte register is set. An error/status message is cleared from the error queue when it is read. The error queue is considered cleared when it is empty. An empty error queue clears the EAV bit in the status byte register.

The error queue holds up to 10 error/status messages. The commands to read the error queue are listed in Table 7-6. When you read a single message in the error queue, the “oldest” message is read and then removed from the queue. If the queue becomes full, the message “350, ‘queue overﬂow’” will occupy the last memory location. On power-up, the error queue is empty. When empty, the message “0, No Error” is placed in the queue.

Messages in the error queue are preceded by a code number. Negative (-) numbers are used for SCPI deﬁned messages, and positive (+) numbers are used for Keithley deﬁned messages. The messages are listed in Appendix B.

On power-up, all error messages are enabled and will go into the error queue as they occur. Status messages are not enabled and will not go into the queue. As listed in Table 7-7, there are commands to enable and/or disable messages. For these commands, the <list> parameter is used to specify which messages to enable or disable. The messages are speciﬁed by their codes. The following examples show various forms for using the <list> parameter.

<list> = (-110) Single message

= (-110:-222) Range of messages (-110 through -222)

= (-110:-222, -220) Range entry and single entry (separated by a comma)

When you enable messages, messages not speciﬁed in the list are disabled. When you disable messages, each listed message is removed from the enabled list.

Keithley Keithley Instruments 2303 Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Table of Contents

List of Illustrations

List of Tables

Getting Started

General information

Power supply overview

Remote display option

Power-up

Display modes

Default settings

Menu

SCPI programming

Basic Power Supply Operation

Test connections

Outputting voltage and current

Reading back V and I

Independent voltage measur ements (D VM)

Sink operation

Progr amming examples

Pulse Current Measurements

Overview

Average readings count

SCPI programming

Long Integration Measurements

Overview

Long integration measurement procedure

SCPI programming

Relay Control

Overview

Connections

Controlling the relay

GPIB Operation

Introduction

GPIB bus connections

Primary address

Output format

General bus commands

Front panel aspects of GPIB operation

Programming syntax

Status Structure

Overview

Clearing registers and queues

Programming and reading registers

Status byte and service request (SRQ)

Status register sets

Queues