Keithley 2750 User guide

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Model 2750 Multimeter/Switch System

User’s Manual

2750-900-01 Rev. F / August 2011

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ECNEDIFNOC FO ERUSAEM RETAERG A

Model 2750 Multimeter/Switch System

User’s Manual

2011, Keithley Instruments, Inc.

Cleveland, Ohio, U.S.A.

Document Number: 2750-900-01 Rev. F

Safety Precautions

04/09

The following safety precautions should be observed before using this product and any associated instrumentation. Although some instruments and accessories would normally be used with 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 user documentation for complete product specifications.

If the product is used in a manner not specified, the protection provided by the product warranty may be impaired. The types of product users are: Responsible body is the individual or group responsible for the use and maintenance of equipment, for ensuring

that the equipment is operated within its specifications and operating limits, and for ensuring that operators are adequately trained.

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

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

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

Keithley Instruments products are designed for use with electrical signals that are 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 user documentation.

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 1000V , no conductive part

of the circuit may be exposed. Do not connect switching cards directly to unlimited power circuits. They are intended to be used with impedance-

limited sources. NEVER connect switching cards directly to AC mains. When connecting sources to switching cards, install protective devices to limit fault current and voltage to the card.

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

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

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

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

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 the same type and rating for continued protection against fire hazard. Chassis connections must only be used as shield connections for measuring circuits, NOT as 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 means caution, risk of danger. The user should refer to the operating instructions

located in the user documenta ti on in all case s wh ere th e symb ol is ma rked on the instrument. The symbol on an instrument means caution, risk of danger. Use standard safety precautions to avoid personal

contact with these voltages. The symbol on an instrument shows that the surface may be hot. Avoid personal contact to prevent burns. The symbol indicates a connection terminal to the equipment frame.

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

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

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

Instrumentation and accessories shall not be connected to humans. Before performing any maintenance, disconnect the line cord and all test cables. To maintain protection from electric shock a nd 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.

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

1 Getting Started

General information ................................................................................. 1-2

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

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

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

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

Model 2750 features ................................... .................................. ............ 1-5

Plug-in switching modules ....................................................................... 1-6

Pseudocards ...................................................................................... 1-8

Identifying installed switching modules ........................................... 1-8

Front and rear panel familiarization ......................................................... 1-9

Front panel summary ........................................................................ 1-9

Rear panel summary ....................................................................... 1-12

Rack mounting ....................................................................................... 1-13

Power-up ................................................................................................ 1-14

Line power connection .................................................................... 1-14

Line frequency ................................................................................ 1-15

Setting line voltage and replacing fuse ........................................... 1-15

Power-up sequence ......................................................................... 1-16

Keyclick .......................................................................................... 1-16

Display ................................................................................................... 1-17

Status and error messages ............................................................... 1-17

Remote programming — display .................................................... 1-17

Defaults and user setups ......................................................................... 1-19

Saving and restoring setups ............................................................ 1-20

Remote programming — default and user setups ........................... 1-24

Remote programming information ......................................................... 1-25

Quick start exercises .............................................................................. 1-25

Basic DMM measurements — front panel inputs .......................... 1-26

Closing and opening channels — system channel operation .......... 1-28

Simple scanning .............................................................................. 1-31

Trigger and return readings — remote programming ..................... 1-34

2 Closing and Opening Switching Module Channels

Close/open overview ................................................................................ 2-2

Switching module installation and connections ....................................... 2-3

Module installation ........................................................................... 2-3

Connections ...................................................................................... 2-5

Pseudocards ...................................................................................... 2-6

Channel assignments ................................................................................ 2-6

System channel operation ........................................................................ 2-7

2-wire functions ........................................ ......................................... 2-8

4-wire functions (paired channels) ................................................... . 2-8

Controlling the system channel ......................................................... 2-9

Non-amp and non-measure switching modules .............................. 2-13

Multiple channel operation .................................... ................................. 2-15

Controlling multiple channels ......................................................... 2-17

Multiple channel operation anomalies ............................................ 2-21

Dual independent multiplexers ........................................................ 2-23

Identifying installed modules and viewing closed c hannels .................. 2-28

CARD menu ............................................. .................................. ..... 2-28

Switching module queries (remote operation) ................................ 2-30

Relay closure count ................................................................................ 2-32

Reading relay closure count ............................................................ 2-33

Setting count update interval ........................................................... 2-33

Model 7700 switching module .......................................................... ... .. 2-34

Switching module capabilities ........................................................ 2-34

Schematic diagram ................................ .......................................... 2-35

3 Basic DMM Operation

DMM measurement capabilities ............................................................... 3-2

High energy circuit safety precautions ..................................................... 3-3

Performance considerations ...................................................................... 3-4

Warm-up ............................................................................................ 3-4

Autozero ............................................................................................ 3-4

LSYNC (line cycle synchronization) ................................................ 3-5

Remote programming — autozero and LSYNC ............................... 3-6

Channel list parameter (<clist>) ............................................................... 3-7

Voltage measurements (DCV and ACV) .................................................. 3-8

DCV input divider ............................................................................ . 3-8

Connections ....................................................................................... 3-8

Volts measurement procedure ......................................................... 3-11

Crest factor .............................. .................................. ...................... 3-12

Low level considerations ................................................................. 3-12

Current measurements (DCI and ACI) ................................................... 3-14

Connections ..................................................................................... 3-14

Amps measurement procedure ........................................................ 3-15

AMPS fuse replacement (front panel AMPS input) ........................ 3-16

Resistance measurements (Ω2 and Ω4) .................................................. 3-16

Connections ..................................................................................... 3-17

Standard resistance measurements .................................................. 3-19

Offset-compensated ohms ............................................................... 3-20

Dry circuit ohms (DRYCKT) .......................................................... 3-22

Temperature measurements .................................................................... 3-25

Thermocouples ................................................................................ 3-25

Thermistors ..................................................................................... 3-27

4-wire RTDs .............................................................. ...................... 3-28

Connections .................................................................................... 3-28

Temperature measurement configuration ........................................ 3-34

Temperature measurement procedure ............................................. 3-37

Frequency and period measurements ..................................................... 3-38

Trigger level ................................................... ................................. 3-38

Gate time ......................................................................................... 3-38

Connections .................................................................................... 3-39

Frequency and period measurement procedure .............................. 3-40

Continuity testing ........................................................................... ........ 3-41

Connections .................................................................................... 3-41

Continuity testing procedure ........................................................... 3-42

Remote programming for basic measurements ...................................... 3-43

Basic measurement commands ....................................................... 3-43

Basic measurement programming examples .................................. 3-49

Measurement queries ............................................................................. 3-50

:FETCh? .......................................................................................... 3-50

:READ? ........................................................................................... 3-51

:MEASure[:<function>]? ................................................................ 3-51

[:SENSe[1]]:DATA:FRESh? ........................................................... 3-52

[:SENSe[1]]:DATA[:LATest]? ........................................................ 3-52

Examples ......................................................................................... 3-53

4 Range, Digits, Rate, Bandwidth, and Filter

Range ....................................................................................................... 4-2

Measurement ranges and maximum readings ................................... 4-2

Manual ranging ................................................................................. 4-2

Auto ranging ..................................................................................... 4-3

Scanning ............................................................................................ 4-3

Remote programming — range ........................................................ 4-4

Digits ........................................................................................................ 4-5

Scanning ............................................................................................ 4-5

Remote programming — digits ........................................................ 4-6

Rate and bandwidth .................................................................................. 4-8

Rate ................................................................................................... 4-8

Bandwidth ....................................................................................... 4-10

Scanning .......................................................................................... 4-10

Remote programming — rate and bandwidth ................................. 4-11

Filter ....................................................................................................... 4-14

Filter characteristics ........................................................................ 4-14

Remote programming — filter ........................................................ 4-19

5 Relative, Math, Ratio, ChannelAver age, and dB

Relative ..................................................................................................... 5-2

Basic operation .................................................................................. 5-2

Remote programming — rel ............................................................. 5-4

Math .......................................................................................................... 5-8

mX+b ................................................................................................. 5-9

Percent ............................................................................................. 5-10

Reciprocal (1/X) .............................................................................. 5-11

Basic operation ................................................................................ 5-12

Remote programming — math ........................................................ 5-13

Ratio and channel average ..................................... ................................. 5-16

Basic operation ................................................................................ 5-17

Remote programming — ratio and channel average ....................... 5-19

dB ........................................................................................................... 5-21

Remote programming — dB ........................................................... 5-21

6Buffer

Buffer overview ........................................................................................ 6-2

Front panel buffer ..................................................................................... 6-2

Auto clear .......................................................................................... 6-2

Timestamps ....................................................................................... 6-3

Storing readings ................................................................................. 6-5

Recalling readings ............................................................................. 6-6

Buffer statistics .................................................................................. 6-7

Remote programming — buffer ......................... .................................. .... 6-8

Buffer commands .............................................................................. 6-8

Programming example .................................................................... 6-15

7 Scanning

Scanning fundamentals ............................................................................. 7-2

Channel assignments ......................................................................... 7-3

Sequential and non-sequential scans ................................................. 7-3

Scan process .............................................................. ... ..................... 7-3

Trigger models .................................................................................. 7-4

Scan configuration .................................................................................. 7-11

Scan reset ......................................................................................... 7-13

Simple scan ..................................................................................... 7-13

Advanced scan ................................................................................. 7-14

Setting delay .................................................................................... 7-17

Monitor channel .............................................................................. 7-18

Auto channel configuration ............................................................. 7-19

Saving setup .................................................................................... 7-20

Auto scan ......................................................................................... 7-20

Scan operation ............................................ ............................................ 7-21

Basic scan ........................................................................................ 7-21

Manual/external trigger scan ........................................................... 7-22

Monitor scan (analog trigger) ......................................................... 7-23

Remote programming — scanning ........................................................ 7-25

Trigger model .......................................................... ........................ 7-25

Channel setup .................................................................................. 7-26

Buffer .............................................................................................. 7-26

Scanning commands ....................................................................... 7-26

Scanning programming example .................................................... 7-31

Scanning examples ................................................................................. 7-32

External trigger scan ....................................................................... 7-32

Monitor scan ................................................................................... 7-35

8 T riggering

Trigger model ................................................................................. .......... 8-2

Idle .................................................................................................... 8-2

Control source and event detection ................................................... 8-3

Delay (auto or manual) ..................................................................... 8-3

Device action .................................................................................... 8-5

Output trigger .......................................................... .......................... 8-5

External triggering ................................................................................... 8-6

Digital I/O ......................................................... ................................ 8-6

External trigger ................................................................................. 8-7

Voltmeter complete ........................................................................... 8-7

External triggering example .............................................................. 8-8

External triggering with BNC connections ..................................... 8-11

Remote programming — triggering ....................................................... 8-12

Trigger model (remote operation) .............................................. ..... 8-12

Trigger model operation ......................................................... ........ 8-15

Triggering commands ............................................................. ........ 8-16

Programming example .................................................................... 8-17

9 Limits and Digital I/O

Limits ....................................................................................................... 9-2

Scanning ............................................................................................ 9-4

Basic limits operation ....................................................................... 9-4

Digital I/O ................................................................................................ 9-5

Digital input (trigger link input) ....................................................... 9-5

Digital outputs .......................................... ......................................... 9-6

Setting digital output ....................................................................... 9-11

Scanning .......................................................................................... 9-12

Remote programing — limits and digital output ................................... 9-13

Limits and digital output commands .............................................. 9-13

Limits and digital outputs programming example .......................... 9-15

Application — sorting resistors ............................................................. 9-16

Limits .............................................................................................. 9-16

Digital outputs ................................................................................. 9-18

10 Remote Operations

Operation enhancements ........................................................................ 10-2

Pseudocards ..................................................................................... 10-2

Autozero .......................................................................................... 10-2

dB calculation .................................................................................. 10-2

Separate function setups .................................................................. 10-3

DCV input divider ........................................................................... 10-3

Multiple channel operation .............................................. ................ 10-3

GPIB setup .............................................................................................. 10-4

GPIB standards ................................................................................ 10-4

Selecting GPIB and setting primary address ................................... 10-4

GPIB connections ............................................................................ 10-5

General bus commands ........................................................................... 10-7

REN (remote enable) ....................................................................... 10-8

IFC (interface clear) ........................................................................ 10-8

LLO (local lockout) ................................................ ......................... 10-8

GTL (go to local) ............................................................................. 10-8

DCL (device clear) .......................................................................... 10-9

SDC (selective device clear) ........................................................... 10-9

GET (group execute trigger) ........................................................... 10-9

SPE, SPD (serial polling) ................................................................ 10-9

Front panel GPIB operation .................................................................. 10-10

Error and status messages ............................................................. 10-10

GPIB status indicators ................................................................... 10-10

LOCAL key ................................................................................... 10-11

Programming syntax ............................................................................. 10-11

Command words ........................................................................... 10-11

Query commands ........................................................................... 10-13

Case sensitivity .................................................. ............................ 10-13

Long-form and short-form versions .............................................. 10-14

Short-form rules ............................................................................ 10-14

Program messages ..................................................... .................... 10-15

Response messages ....................................................................... 10-17

Message exchange protocol ...................................... .................... 10-17

RS-232 interface operation ................................................................... 10-18

Sending and receiving data ............................................................ 10-18

Baud rate .................................... ................................................... 10-18

Signal handshaking (flow control) .................................. .............. 10-19

Terminator ..................................................................................... 10-19

Selecting and configuring RS-232 interface ................................. 10-20

RS-232 connections ....................................................................... 10-20

Error messages .............................................................................. 10-21

11 Status Structure

Overview ................................................................................................ 11-2

Status byte and SRQ ....................................................................... 11-2

Status register sets ........................................................................... 11-2

Queues ............................................................................................ 11-2

Clearing registers and queues ................................................................. 11-4

Programming and reading registers ....................................................... 11-5

Programming enable registers ......................................................... 11-5

Reading registers ............................................................................. 11-6

Status byte and service request (SRQ) ................................................... 11-6

Status byte register .......................................................................... 11-7

Service request enable register ........................................................ 11-8

Serial polling and SRQ ................................................................... 11-8

Status byte and service request commands ..................................... 11-9

Serial poll programming example ................................................... 11-9

Status register sets ................................................................................ 11-11

Condition registers ........................................................................ 11-18

Event registers ............................................................................... 11-18

Event enable registers ................................................................... 11-19

Queues .................................................................................................. 11-20

Output queue .................................... .................................. ........... 11-20

Error queue ................................................................................... 11-20

12 Common Commands 13 SCPI Signal Oriented Measurement Commands

CONFigure:<function> [<rang>], [<res>], [<clist>] ............................ 13-3

FETCh? .................................................................................................. 13-5

READ? ................................................................................................... 13-5

MEASure:<function>? [<rang>], [<res>], [<clist>] ............................. 13-7

14 FORMat and Miscellaneous SYST em Commands

FORMat commands ............................................................................... 14-2

FORMat[:DATA] <type>[,<length>] ............................................. 14-2

FORMat:ELEMents <item list> .................................................... 14-5

FORMat:BORDer <name> ............................................................ 14-6

Miscellaneous SYSTem commands ....................................................... 14-7

SYSTem:PRESet ............................................................................. 14-7

SYSTem:VERSion .......................................................................... 14-7

SYSTem:KEY <NRf> ................................................................... 14-7

SYSTem:BEEPer[:STATe] ..................................................... 14-8

15 SCPI Reference Tables

Reference tables ...................................................................................... 15-2

B Model 7700 Connection Guide

Card configuration — schematic ............................................................. B-2

Connections and wiring ........................................................................... B-4

Screw terminals ................................................................................ B-5

Wiring procedure .............................................................................. B-6

Typical connections .......................................................................... B-7

Connection log ............................................................................... B-10

C Status and Error Messages D Signal Processing Sequence and Data Flow

Signal processing sequence ............................. ........................................ D-2

Basic signal processing .................................................................... D-2

Signal processing using instrument features .............................. ...... D-3

Signal processing using Ratio or Ch Avg ......................................... D-6

Data flow (remote operation) .................................................................. D-7

SENSe and sample buffer ................................................................. D-8

[SENS[1]]:DATA[LATest]? .............................................................. D-9

[SENS[1]]:DATA:FRESh? ............................................................... D-9

FETCh? ............................................................................................ D-9

READ? ............................................................................................. D-9

MEASure? ........................................................................................ D-9

CALC[1]:DATA[LATest]? ............................................................... D-9

CALC[1]:DATA:FRESh? ................................................................. D-9

CALC3:LIM1:FAIL? ..................................................................... D-11

CALC3:LIM2:FAIL? ..................................................................... D-11

TRACe:DATA? ............................................................................... D-11

CALC2:IMM? ................................................................................ D-12

CALC2:IMM .................................................................................. D-12

CALC2:DATA? .............................................................................. D-12

Continuous measurement mode ..................................................... D-12

Scanning ......................................................................................... D-13

E Measurement Considerations

Measurement considerations ......................................... ........................... E-2

Thermoelectric potentials .................................................................. E-2

Thermoelectric generation ................................................................. E-3

Minimizing thermal EMFs ................................................................ E-4

Source resistance noise ..................................................................... E-5

Magnetic fields .................................................................................. E-6

Radio frequency interference ............................................................ E-6

Ground loops ..................................................................................... E-7

Shielding ........................................................................................... E-9

Meter loading .................................................................................. E-10

F T emper ature Equations

Thermocouple equation ............................................................................ F-2

Thermistor equation ................................................................................. F-6

RTD equation ........................................................................................... F-8

G IEEE-488 Bus Overvie w

Introduction .............................................................................................. G-2

Bus description ......................................................................................... G-2

Bus lines ................................................................................................... G-4

Data lines .......................................................................................... G-4

Bus management lines ...................................................................... G-5

Handshake lines ................................................................................ G-5

Bus commands ......................................................................................... G-6

Uniline commands ................................... .................................. ....... G-8

Universal multiline commands ......................................................... G-8

Addressed multiline commands ........................................................ G-9

Address commands ........................................................................... G-9

Unaddress commands ....................................................................... G-9

Common commands ....................................................................... G-10

SCPI commands ........................................................ ...................... G-10

Command codes .............................................................................. G-10

Typical command sequences ........................................................... G-12

IEEE command groups .................................. ................................. G-13

Interface function codes ......................................................................... G-14

Getting Started

Quick Start — Of the following section topics, three can be used immediately to quickly acquaint yourself with fundamental instrument operations. Use QS1 to familiarize yourself with front panel controls, use QS2 to power-up the instrument, and, finally, use QS3 to perform exercises to operate the instrument.

• General information — Covers general information that includes contact infor-

mation, safety symbols and terms, inspection, and available options and accessories.

• Model 2750 features — Summarizes the features of Model 2750.

• Plug-in switching modules — Summarizes the capabilities of the Keithley

Model 77XX series switching modules.

QS1 • Front and rear panel familiarization — Summarizes the controls and connectors

of the instrument.

• Rack mounting — Covers the options av ailable for rack mounting the Model 2750

in a standard 19-inch rack.

QS2 • Power-up — Co vers line po wer connection, line v oltage setting, fuse replacement,

power line frequency, and the power-up sequence.

• Display — Provides information about the display of the Model 2750.

• Defaults and user setups — Lists the *RST and factory default settings, and cov-

ers the three setup configurations available to the user.

• Remote programming information — Explains how SCPI commands are pre-

sented in this manual.

QS3 • Quick start exercises — Provides abbreviated operating information and exercises

(front panel and remote programming) to acquaint a user with operation basics.

1-2 Getting Started Model 2750 Multimeter/Switch System User’s Manual

General information

Contact information

W orldwide phone numbers are listed at the front of this manual. If you have any questions, please contact your local Keithley representative or call a Keithle y Application Engineer at 1-800-348-3735 (U.S. and Canada only).

Safety symbols and terms

The following symbols and terms may be found on the instrument or used in this manual: The symbol on an instrument indicates that the user should refer to the operating

instructions located in the manual. The symbol on the instrument shows that high voltage may be present on the termi-

nal(s). Use standard safety precautions to avoid personal contact with these voltages. The WARNING heading used in this manual explains dangers that might result in per-

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

The CAUTION heading used in this manual explains hazards that could damage the instrument. Such damage may invalidate the warranty.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-3

Inspection

Model 2750 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. (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 Model 2750 order:

• Model 2750 with line cord.

• Safety test leads (Model 1751).

• Accessories as ordered.

• Hardware for rack mounting.

• Certificate of calibration.

• Model 2750 User’s Manual (P/N 2750-900-00).

• Manual Addenda (pertains to any improvements or changes concerning the instrument or manual).

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

Options and accessories

Plug-in switching modules

NOTE Table 1-1 provides a side-by-side comparison of the following Keithley switch-

ing modules. All multiplexer modules can be configured as two independent multiplexers.

NOTE The Model 77XX Series Switching Modules Instruction Manual pro vides oper at-

ing and service information for the switching modules. This manual is supplied with each switching module.

Model 7700 — This differential multiplexer provides 20 channels of 2-pole input, or 10 channels of 4-pole input. The internal cold junction allows direct-connection of thermocouples. It also has two 2-pole channels used exclusively for current input.

Model 7701 — This differential multiplexer provides 32 channels of 2-pole input, or 16 channels of 4-pole input.

Model 7702 — This differential multiplexer provides 40 channels of 2-pole input, or 20 channels of 4-pole input. It also has two 2-pole channels used exclusively for current input.

1-4 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Model 7703 — This differential multiplexer provides 32 channels of 2-pole input, or 16 channels of 4-pole input.

Model 7705 — This control module provides 40 independent 1-pole switching (SPST) channels that are isolated from the internal DMM.

Model 7706 — This all-in-one module provides 20/10 channels of 2/4-pole input, 16 digital outputs, two analog outputs, one 32-bit counter with gating and totalizer.

Model 7707 — This module provides 10 channels of 2-pole input, or 5 channels of 4-pole input. Also provides 32 digital inputs/outputs.

Model 7708 — This differential multiplexer provides 40 channels of 2-pole input, or 20 channels of 4-pole input. The internal cold junction allows direct-connection of thermocouples for temperature measurements.

Model 7709 — This module is configured as a 6 × 8 matrix (six rows, eight columns). The matrix consists of 48 crosspoint channels and two backplane isolation channels. For system channel operation, row 1 is connected to DMM Input. For 4-wire measurements, row 2 is connected to DMM Sense.

Connector and adapter kits for switching modules

Model 7788 DB-50 connector kit — Contains two male DB-50 solder cup connectors with strain relief connector shells. These connectors mate to the female connectors of the Models 7703 and 7705 switching modules.

Model 7789 50/25-pin solder cup connector kit — Contains one male DB-50 and one male DB-25 solder cup connectors. These connectors mate to the female connectors on the Models 7701 and 7709 switching modules.

Model 7790 ribbon cable adapter kit — Contains one female DB-50, one male DB-50 and one male DB-25 IDC ribbon cable connectors. These connectors are used with the Models 7701, 7707 and 7709 switching modules.

Cables and adapters (GPIB and trigger link)

Models 7007-1 and 7007-2 shielded GPIB cables — Connect Model 2750 to the GPIB bus using shielded cables and connectors to reduce electromagnetic interference (EMI). Model 7007-1 is one meter long; Model 7007-2 is two meters long .

Models 8501-1 and 8501-2 trigger link cables — Connect Model 2750 to other instruments with Trigger Link connectors (e.g., Model 7002 Switch System). Model 8501-1 is one meter long; Model 8501-2 is two meters long.

Model 8502 trigger link adapter — Lets you connect any of the six trigger link lines of Model 2750 to instruments that use the standard BNC trigger connectors.

Model 8503 DIN to BNC trigger cable — Lets you connect trigger link lines one (Voltmeter Complete) and two (External Trigger) of Model 2750 to instruments that use BNC trigger connectors. Model 8503 is one meter long.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-5

Rack mount kit

Model 4288-7 rack mount kit — Mounts a Model 2750 in a standard 19-inch rack. Includes rear brackets to provide additional support for a mainframe that has two or more switching modules installed.

NOTE The Model 2750 includes hardwar e that allows it to be mounted to the front rails

of a standard 19-inch rack. With two or more switching modules installed, rear support brackets may be required. The Model 4288-7 rack mount kit includes rear support brackets.

Model 2750 features

Model 2750 is a 6H-digit high-performance multimeter/data acquisition system. It can mea- sure voltage (DC and AC), current (DC and AC), resistance (2- and 4-wire), temperature (thermocouple, thermistor, and 4-wire RTD), frequency and period, and test continuity.

The Model 2750 has five slots that will accommodate Keithley Model 7700 series switching modules ( measured by the Model 2750. For scanning, each channel can have its own unique setup (i.e., function, range, digits, etc.).

Table 1-1). Each channel of a switching modul e that is closed or scanned is

More information on the measurement capabilities of the Model 2750 is provided in

“DMM measurement capabilities,” page 3-2. A connection guide for the Model 7700 is

provided in Appendix B. Additional features of Model 2750 include:

• Setup storage — Five instrument setups (three user, *RST defaults and factory defaults) can be saved and recalled.

• Offset compensated ohms — A two-measurement process for 4-wire ohms to cancel the effects of thermal EMFs. Available for the 1Ω, 10Ω, 100Ω, 1kΩ, and 10kΩ, ranges.

• Dry circuit ohms — Low voltage mode (20mV open-circuit clamping) for 4-wire ohms measurements. Available for the 1Ω, 10Ω, 100Ω, and 1kΩ ranges.

• Math — mX+b, percent, and reciprocal (1/X) calculations provide mathematical manipulation of readings.

• Relative — Null offsets or establish baseline values.

• Ratio and channel average — Ratio and average calculations for two switching module channels.

• Buffer — Store up to 110,000 readings in the internal buffer.

• Limits — Two sets of high and low reading limits to test devices.

1-6 Getting Started Model 2750 Multimeter/Switch System User’s Manual

• Digital I/O port — Five digital limit test output lines to control external circuitry.

The digital trigger link and hardware interlock input can also be accessed at this port.

• Monitor — The Model 2750 can monitor a selected channel. A scan can be trig-

gered to start when the Monitor detects a reached reading limit.

• Remote interface — Model 2750 can be controlled using the IEEE-488 interface

(GPIB) or the RS-232 interface.

Plug-in switching modules

Up to five Keithley Model 77XX series switching modules can be installed in the Model

2750. A side-by-side comparison of the switching modules is provided in Table 1-1. Basic close/open operation for switching module channels is provided in Section 2,

while scanning is covered in Section 7. Connec tion i nforma tion fo r the Mo del 77 00 switching module is provided in Appendix B. For all other switching modules, connection information is provided in the packing list that was shipped with each switching module.

Table 1-1

Model 77XX series switching modules

2-pole operation 4-pole operation 1-pole operation Measure volts Measure amps

Measure ohms Cold junction

for thermocouples

Relay type

Connector type

Configuration

Unique features

Model 7700 Model 7701 Model 7702 Model 7703 Model 7705

20 channels 10 channel pairs N/A 300V Max Ch 21 and 22, 3A Max 2/4-wire Yes

Latching electromechanical Oversized screw terminals Multiplexer

All DMM functions

32 channels 16 channel pairs N/A 150V Max No

2/4-wire No

Latching electromechanical 1 female DB-50 1 female DB-25 Multiplexer

All DMM functions except amps

40 channels 20 channel pairs N/A 300V Max Ch 41 and 42, 3A Max 2/4-wire No

Latching electromechanical Oversized screw terminals Multiplexer

All DMM functions

32 channels 16 channel pairs N/A 300V Max No

2/4-wire No

Non-latching reed 2 female DB-50s Multiplexer

All DMM functions except amps

N/A N/A 40 channels 300V Max No

No No

Latching electromechanical 2 female DB-50s Independent SPST channels Multiple channel operation only

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-7

Table 1-1 (continued)

Model 77XX series switching modules

Model 7706 Model 7707 Model 7708 Model 7709

2-pole operation 4-pole operation 1-pole operation Measure volts Measure amps Measure ohms Cold junction

20 channels 10 channel pairs N/A 300V Max No 2/4-wire Yes

10 channels 5 channel pairs N/A 300V No 2/4-wire No

40 channels 20 channel pairs N/A 300V Max No 2/4-wire Yes

8 channels 4 channel pairs N/A 300V Max No 2/4-wire No

for thermocouples

Relay type

Connector type

Configuration Unique features

Latching electromechanical Mini screw terminals

Multiplexer 16 digital outputs, 2 analog outputs, one counter, totalizer

Latching electromechanical 1 male DB-50 1 female DB-25 Multiplexer 32 digital inputs/outputs

Latching electromechanical Oversized screw terminals Multiplexer All DMM functions except amps

Latching electromechanical 1 female DB-50 1 female DB-25 Matrix 6 × 8 matrix. For system channel operation, rows 1 and 2 connect to DMM

1. Latching relays hold their open/close state after the Model 2750 is turned off. When turned on, all relays open after a few seconds.

2. All multiplexers can be configured as two independent multiplexers.

1-8 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Pseudocards

Using remote programming, you can assign a pseudocard to an empty switching module slot. With a pseudocard “installed,” the Model 2750 will operate as if the switching module is installed in the Model 2750. This feature allows you to configure your system without having the actual switching module installed in the unit. There is a pseudocard for every Keithley Model 77XX series switching module. For details, see “Pseudocards,”

page 2-6.

Identifying installed switching modules

On power-up, the model numbers of installed switching modules are displayed briefly. While in the normal display state, slot indicators on the right side of the display indicate which slots have a switching module or pseudocard installed.

NOTE If a Model 7700, 7701, 7702, 7703, 7705, 7708, or 7709 switching module is

removed while the Model 2750 is on, the slot indicator for that slot will remain on, and the instrument will operate as if the module is installed. That is, the Model 2750 will operate as if the pseudocard is installed.

If a Model 7706 or 7707 is removed while power is on, error +523 “Card hardware error” will occur, and the module will be removed from the system.

In general, it is not recommended to install or remove switching modules with the power on.

The CARD menu and remote query commands can be used to identify modules installed in the mainframe. For details, see “Switching module installation and connections,”

page 2-3.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-9

MODEL 2750 MULTIMETER/SWITCH SYSTEM

INTEGRA SERIES

SLOT 1

SLOT 3 SLOT 4 SLOT 5

SLOT 2

3A, 250V

MATH

OUTPUT

RATIO

CH AVG

CONT

PERIOD SENSOR

OCOMP

DCV

DCIACV

ACIΩ2Ω4

FREQ

TEMP

RANGE

AUTO

RANGE

EXIT ENTER

DIGITS RATE

RELFILTER

TRIG

EX TRIG

STORE

RECALL

OPEN

LIMITS ON/OFFDELAY

DRYCKT

SAVE SETUP

CONFIG HALT

TYPE

LSYNC

TEST

MONITOR

STEP SCAN

CH-OFF CARD

RS-232

GPIB

POWER

SHIFT

LOCAL

500V PEAK

FRONT/REAR

INPUT

SENSE

Ω 4 WIRE

INPUT

350V PEAK

1000V PEAK

CAT I

AMPS

Fr ont and rear panel familiarization

Front panel summar y

The front panel of Model 2750 is shown in Figure 1-1.

Figure 1-1

Model 2750 front panel

NOTE Most keys provide a dual function or operation. The nomenclature on a key indi-

cates its unshifted function/operation, which is selected by pressing the key. Nomenclature (in blue) above a key indicates its shifted function. A shifted function is selected by pressing the SHIFT key and then the function/operation key.

1 Special keys and power switch:

SHIFT Use to select a shifted function or operation. LOCAL Cancels GPIB remote mode. POWER Power switch. In position turns 2750 on (I), out position turns it off (O).

2 Function and operation keys:

Top Row

Unshifted DCV Selects DC voltage measurement function. ACV Selects AC voltage measurement function. DCI Selects DC current measurement function. ACI Selects AC current measurement function.

Ω2 Selects 2-wire resistance measurement function. Ω4 Selects 4-wire resistance measurement function.

FREQ Selects frequency measurement function. TEMP Selects temperature measurement function.

Shifted MATH Configures and controls mX+b, percent, or reciprocal (1/X) calculation. OUTPUT Configures and controls digital and audio (beeper) output for limits. RATIO Enables/disables channel ratio. CH-AVG Enables/disables channel average. CONT Configures and controls continuity test. OCOMP Enables/disables offset compensated ohms with Ω4 function selected. PERIOD Selects period measurement function. SENSOR Configures temperature measurements.

1-10 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Middle Row

Unshifted EXTRIG Selects external triggering (front panel, bus, trigger link) as the trigger source. TRIG Triggers a measurement when in external triggering (EX TRIG). STORE Sets the number of readings to store and enables the buffer. RECALL Displays stored readings and buffer statistics. Use the

igate through buffer. FILTER Enables/disables filter for selected function. REL Enables/disables relative for selected function.

, , Δ , and ∇ keys to nav-

 and  Dual function — Manually scans switching channels. When in a menu, these keys

control cursor position for making selections or change values. Shifted DELAY Sets user delay between trigger and measurement. DRYCKT Selects dry circuit ohms (Ω4 must first be selected). LIMITS Sets upper and lower limits for readings. ON/OFF Enables/disables limits. TYPE Configures and enables filter for selected function. MONITOR Selects and enable/disables monitor channel. CH-OFF Disables channel for a scan (must be in scan channel setup mode). CARD Identifies switching modules installed in mainframe. Set up switching modules that

Bottom Row

Unshifted OPEN Opens closed channel. CLOSE Closes specified channel. STEP Steps through channels; sends a trigger after each channel. SCAN Scans through channels; sends a trigger after last channel. DIGITS Sets display resolution for all functions. RATE Sets measurement speed (fast, medium, or slow) for all functions. EXIT Cancels selection, moves back to measurement display. ENTER Accepts selection, moves to next choice or back to measurement display. Shifted SAVE Saves up to three instrument setups for future recall, and selects power-on setup. SETUP Restores a default setup (factory or *RST) or a saved setup. Enables/disables buffer

CONFIG Selects and configures a simple scan or an advanced scan. HALT Disables step/scan. TEST Selects the calibration menu, display test or the key-press test. LSYNC Enables/disables line cycle synchronization. When enabled, noise induced by the

GPIB Enables/disables GPIB and selects address. RS-232 Enables/disables RS-232 interface; selects baud rate, flow control, and terminator.

require configuration. View closed channels and channel settings for switching mod-

ules that require configuration.

auto clear, auto scan, and auto channel configuration. Sets timestamp, date, and

time. Displays serial number of Model 2750.

power line is reduced at the expense of speed.

3 Range keys:

Δ and ∇ Dual function — Selects the next higher/lower measurement range for the selected

function. When in a menu, these keys make selections or change values. AUTO Enables/disables autorange for the selected function.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-11

4 Display annunciators:

* (asterisk) Readings being stored in buffer. ↔ (more) Indicates additional selections are available. ))) (speaker) Beeper on for continuity or limits testing.

4W 4-wire resistance or 4-wire RTD temperature reading displayed. DCKT Dry circuit resistance reading displayed. ~AC AC function selected (ACV, dB, or ACI). AUTO Auto range enabled. BUFFER Recalling readings stored in buffer. CHAN Setup or a reading for a switching channel displayed. DELTA Channel average enabled. ERR Questionable reading, or invalid cal step. FAST Fast reading rate selected. FILT Filter enabled for selected function. HIGH Reading has reached or exceeded the enabled high limit. LSTN Instrument addressed to listen over GPIB. LOW Reading has reached or exceeded the enabled low limit. MATH mX+b, percent, or reciprocal (1/X) calculation enabled. MED Medium reading rate selected. MON Monitor channel displayed. OCOMP 4-wire offset compensated ohms enabled. RATIO Channel ratio enabled. REAR Front panel input terminals disconnected. REL Relative enabled for selected function. REM Instrument in GPIB remote mode. SCAN Scanning operation being performed. SHIFT Accessing a shifted key. SLOW Slow reading rate selected. SRQ Service request over GPIB. STAT Displaying buffer statistics. STEP Stepping operation being performed. TALK Instrument addressed to talk over GPIB bus. TIMER Timer controlled triggering in use. TRIG External triggering selected (trigger link, TRIG key, or GPIB).

Digital input/output or analog output active (set to non-default value).

5 Slot indicators:

Lit lamp indicates that the slot has a switching module or pseudocard installed in it. When the VIEW option of the CARD menu is used, only the lamp that corresponds to the selected slot is turned on.

6 INPUTS switch:

Use to select front panel inputs (out; F) position, or switching module inputs (in; R) position.

NOTE For remote programming, the following command queries the INPUTS switch

position:

SYSTem:FRSwitch? ' Query INPUTS switch; 0 = rear, 1 = front.

7 Front panel inputs:

INPUT HI and LO Used for DCV, ACV, Ω2, CONT, FREQ, PERIOD, and thermocouple/thermistor

TEMP measurements. SENSE HI and LO Use with INPUT HI and LO for AMPS Use with INPUT LO for DCI and ACI measurements. Amps fuse holder Holds current fuse for front panel amps input.

Ω4 and RTD TEMP measurements.

1-12 Getting Started Model 2750 Multimeter/Switch System User’s Manual

IEEE-488

MADE IN

U.S.A.

CAT I

DIGITAL I/O TRIG. LINK

SLT

RS-232

KEITHLEY

SLOT COVER

KEITHLEY

SLOT COVER

KEITHLEY

SLOT COVER

4321

Rear panel summary

The rear panel of Model 2750 is shown in Figure 1-2. As shown, slot covers are installed on unused slots.

WARNING Slot covers must be installed on unused slots to prevent personal con-

tact with high voltage circuits.

Figure 1-2

Model 2750 rear panel

1 DIGITAL I/O

Male DB-9 connector for digital input (trigger link in) and digital outputs.

2 TRIG LINK

Eight-pin micro-DIN connector for sending and receiving trigger pulses among connected instruments. Use a trigger link cable or adapter, such as Models 8501-1, 8501-2, 8502, and 8503.

3 RS-232

Female DB-9 connector for RS-232 operation. Use a straight-through (not null modem) DB-9 shielded cable.

4 IEEE-488

Connector for IEEE-488 (GPIB) operation. Use a shielded cable, such as Models 7007-1 and 7007-2.

5 Power module

Contains the AC line receptacle, power line fuse, and line voltage setting. The instrument can be configured for line voltages of 100V/120V/220V/240VAC at line frequencies of 50 or 60Hz.

WARNING Slot covers must be installed on unused slots to prevent personal con-

6 Slots 1 through 5

Five slots to accommodate Keithley Model 77XX series s witching modules. T he Model 2750 is shipped from the factory with slot covers installed. Please note additional slot covers can be requested from Keithley Instruments.

tact with high voltage circuits.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-13

1.75”

Left Front Rack Rail

Retaining Clips with Nuts

Rack mounting

The Model 2750 can be mounted in a standard 19-inch rack. For a mainframe that has one or no switching modules installed, the Model 2750 can be secured to the front rails of the rack.

The hardware necessary to secure the mainframe to the front rails of the rack is supplied with the Model 2750. The supplied hardware kit includes four dress screws and four retaining clips. Each retaining clip has a captive nut.

Perform the following steps to mount the Model 2750 to front rails of the rack:

WARNING Make sure the Model 2750 is turned off, the line cord is disconnected,

and it is not connected to any external circuitry.

1. Select a location in the rack. The mainframe takes up 3H-inches of vertical space.

2. Using Figure 1-3 as a guide, install two retaining clips on the left front rail. Slide

each retaining clip over a mounting hole such that the captive nut is positioned on the inside of the rack cabinet. In a simila r manner, install two retaining clips on the right front rail.

3. Remove the four foot assemblies from the bottom of the Model 2750. The retaining

screw for an assembly is located under the rubber foot. Simply pull off the rubber feet to gain access to the screws. Retain these foot assemblies for future use.

4. Position the Model 2750 in the rack and loosely attach the front panel to the rack

rails using the four supplied dress screws.

5. Tighten the four dress screws.

CAUTION For a Model 2750 that has two or more installed switching modules,

rear brackets are required to support the additional weight. The Model 4288-7 is a rack mount kit for the Model 2750 that uses rear support brackets.

Figure 1-3

Rack preparation

1-14 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Model 2750

IEEE-488

MADE IN

U.S.A.

CAT I

DIGITAL I/O TRIG. LINK

SLT

RS-232

KEITHLEY

SLOT COVER

KEITHLEY

SLOT COVER

KEITHLEY

SLOT COVER

Fuse

Spring

Window

Line Voltage

Selector

Fuse Holder Assembly

120

240

220

100

Power-up

Line power connection

Follow the procedure below to connect the Model 2750 to line power and turn on the instrument.

1. Check to see that the line voltage indicated in the window of the fuse holder assembly (Figure 1-4) is correct for the operating voltage in your area. If not, refer to the next procedure, “Setting line voltage and replacing fuse,” page 1-15.

CAUTION Operating the instrument on an incorrect line voltage may cause dam-

age to the instrument, possibly voiding the warranty.

2. Before plugging in the power cord, make sure that the front panel power switch is in the off (O) position.

3. Connect the female end of the supplied power cord to the A C receptacle on the rear panel. Connect the other end of the power cord to a grounded AC outlet.

WARNING The power cord supplied with the Model 2750 contains a separate

ground wire 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.

4. Turn on the instrument by pressing the front panel power switch to the on (I) position.

Figure 1-4

Power module

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-15

Line frequenc y

The Model 2750 will operate at line frequencies from 45Hz to 66Hz, and 360Hz to 440Hz. There are no user-settings for line frequency. It is automatically sensed at power-up. The following command can be used to read the line frequency:

SYSTem:LFRequency? ' Query power line frequency.

Setting line voltage and replacing fuse

A rear panel fuse located next to the AC receptacle protects the power line input of the instrument. If the line voltage setting needs to be changed or the line fuse needs to be replaced, perform the following steps.

WARNING Make sure the instrument is disconnected from the AC line and other

equipment before changing the line voltage setting or replacing the line fuse.

1. Place the tip of a flat-blade screwdriver into the power module by the fuse holder assembly (Figure 1-4). Gently push in and up. Release pressure on the assembly and its internal spring will push it out of the power module.

2. Remove the fuse and replace it with the type listed in Table 1-2.

CAUTION For continued protection against fire or instrument damage, only

replace fuse with the type and rating listed. If the instrument repeatedly blows fuses, locate and correct the cause of the trouble before replacing the fuse.

3. If configuring the instrument for a different line voltage, remove the line voltage selector from the assembly and rotate it to the proper position. When the selector is installed into the fuse holder assembly, the correct line voltage appears sidew ays in the window.

4. Install the fuse holder assembly into the power module by pushing it in until it locks in place.

Table 1-2

Fuse ratings

Line voltage Fuse rating Keithley P/N

100/120V 220/240V

0.630A, 250V, slow-blow 5× 20mm

0.315A, 250V, slow-blow 5× 20mm

FU-106-.630 FU-106-.315

1-16 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Po wer -up sequence

On power-up, the Model 2750 performs self-tests on its EPROM and RAM and momentarily lights all segments and annunciators. If a failure is detected, the instrument momentarily displays an error message and the ERR annunciator turns on. (Error messages are listed in Appendix C).

NOTE 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 firmware revision levels are displayed. An example of this display is:

REV: A01 A01 where: First A01 is the main board ROM revision.

Second A01 is the display board ROM revision.

Installed switching modules are then displayed. For example, if there is a Model 7700 switching module installed in all five slots, the following messages will be displayed:

1: 7700 2: 7700 3: 7700 4: 7700

5: 7700 If a slot is empty, the message “NONE” will be displayed instead. If the saved power-on setup is not the factory defaults setup (SYSTem:POSetup PRESet),

a message to identify the setup will be briefly displayed (“Defaults and user setups,”

page 1-19).

After the power-up sequence, the instrument begins its normal display of readings.

NOTE The serial number of the Model 2750 can be displayed by selecting the SNUM

Keyclick

With keyclick enabled, an audible “click” will sound when a front panel key is pressed. Perform the following steps to disable or enable keyclick:

item of the SETUP menu. Press SHIFT and then SETUP to access the menu. F or remote operation, the serial number can be read using the *IDN? command (see

Section 12 for details).

1. Press SHIFT and then LOCAL to display the present state of KEYCLICK (ON or OFF).

2. Press

Δ or ∇ to display the desired keycl i c k stat e and pr ess EN TER.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-17

Remote programming

The following command controls keyclick:

SYSTem:KCLick ' Enable or disable keyclick.

where: = ON or OFF

NOTE Keyclick ON is the FACTORY, *RST, and SYSTem:PRESet default.

Display

Readings are displayed in engineering units (i.e., 100.23mV), while annunciators indicate various states of operation. See “Front panel summary ,” page 1-9, for a complete listing of display annunciators.

NOTE The display test allows you to test display digit segments, annunciators and the

red slot indicator LEDs. The key test chec ks the functionality of fr ont panel ke ys. These tests are accessed by pressing SHIFT and then TEST. Refer to the Model 2750 Service Manual for details.

Status and error messages

Status and error messages are displayed momentarily. During operation and programming, you will encounter a number of front panel messages. T ypical messages are either of status or error variety, as listed in Appendix C.

Remote programming — displa y

Using remote programming, the Model 2750 can display a custom ASCII message (up to 12 characters). Also, the front panel display and controls can be disabled.

Display commands

The commands are listed in Table 1-3. Details on these commands follow the table.

NOTE Optional command words and queries are not included in Table 1-3. Table 15-2

provides an unabridged list of all display commands.

Table 1-3

Display commands

Command Description Default*

DISPlay:TEXT:DATA <a> Define message (<a> = ASCII characters,

up to 12).

DISPlay:TEXT:STATe Enable or disable message mode ( = ON

or OFF).

DISPlay:ENABle Enable or disable the front panel display

( = ON or OFF).

*SYSTem:PRESet and *RST have no effect on DISPlay commands. The listed defaults are power-on defa ults.

(none)

OFF

1-18 Getting Started Model 2750 Multimeter/Switch System User’s Manual

DISPlay:TEXT:DA T A <a> Define text message

This command defines the text message for display. A message can be as long as 12 characters. A space counts as a character. Excess message characters results in an error. The characters must be enclosed in either single quotes (‘ ’) or double quotes (“ ”).

DISPlay:TEXT:STA Te ON | OFF Control (on/off) message for display

This command enables and disables the text message mode. When enabled, a defined message is displayed. When disabled, the message is removed from the display.

A user defined text message remains displayed only as long as the instrument is in remote. Taking the instrument out of remote (by pressing the LOCAL key or sending GTL) cancels the message and disables the text message mode.

DISPlay:ENABle ON | OFF Control display circuitry

This command is used to enable and disable the front panel display circuitry. When disabled, the instrument operates at a higher speed. While disabled, the display is blanked.

All front panel controls (except LOCAL) are disabled. Normal display operation can be resumed by using the ENABle command to enab le the display or by putting the Mo d e l 2750 into local mode (press LOCAL).

Programming e xample

The following command sequence displays the text message “TESTING”:

DISP:TEXT:DATA 'TESTING' ' Define text message. DISP:TEXT:STAT ON ' Enable text message mode.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-19

Defaults and user setups

Model 2750 can be restored to one of two default setup configurations (FACTory or *RST), or three user-saved (SAV0, SAV1, or SAV2). As shipped from the factory, Model 2750 powers up to the factory (FACT) default settings.

NOTE Closed channels can be saved in a user setup (SAV0, SAV1, or SAV2). When the

setup is restored, those c hannels (and only those channels) will be closed. FACT and *RST defaults opens all channels.

The factory default setup provides continuous triggering, while the *RST default setup places the Model 2750 in the one-shot trigger mode. With one-shot triggering, a measurement is performed whenever the TRIG key is pressed or an initiate command is sent over the remote interface.

The factory and *RST default settings are listed in Table 1-4. Setting differences (Set Diff) between the two default setups are indicated by checkmarks (✓).

For remote programming, the SYS Tem:PRESet and *RST commands are used to reset the instrument. The *RST command returns the instrument to the *RST defaults and, for the most part, the SYSTem:PRESet command returns the instrument to the factory default conditions. The exceptions are explained as follows:

• Auto scan and auto channel configuration — FACTory defaults disable auto scan and auto channel configuration, while SYSTem:PRESet has no effect. The *RST defaults (front panel and remote operation) have no effect.

• Memory buffer auto clear — FACT ory def a ults enable buffer auto clear , while SYSTem:PRESet has no effect. The *RST defaults (front panel and remote operation) have no effect.

The instrument will power up to whichever default setup is saved as the power-on setup.

NOTE At the factory, the factory default setup is saved as the SAV0, SAV1, or SAV2

setups.

1-20 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Saving and restoring setups

Saving a user setup

1. Configure Model 2750 for the desired measurement application.

2. Press SHIFT and then SAVE to access the save setup menu.

3. Press  to place the cursor on the present setup (SAV0, SAV1, or SAV2).

4. Use the returns to the normal measurement state.

WARNING If you make firmware upgrades you will lose all your saved settings.

Saving a pow er -on setup

1. Configure Model 2750 for the desired measurement application.

2. Press SHIFT and then SAVE to access the save setup menu.

3. Press the SAV0, SAV1, or SAV2.

4. Press  to place the cursor on the present power-on setup.

5. Use the returns to the normal measurement state.

Δ or ∇ key to display the desired setup and press ENTER. The instrument

Δ key to display the present power-on (PWR-ON) setup: FACT, *RST,

Δ or ∇ key to display the desired setup and press ENTER. The instrument

Restoring a setup

1. Press SHIFT and then SETUP to access the restore setup menu.

2. Press  to place the cursor on the present RESTORE setup (FACT, *RST, SAV0, SAV1, or SAV2).

3. Use the returns to the normal measurement state.

NOTE If the settings for a user setup or power-on setup do not match the switching

Δ or ∇ key to display the desired setup and press ENTER. The instrument

module types presently installed in the Model 2750, error +520 (Saved setup scancard mismatch) occurs when the setup is recalled. The scan lis t will reset to the factory defaults and all channels will open. However, the saved setup is still retained in memory and can be restor ed when the matching switching module is later installed.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-21

Table 1-4

Default settings

Setting Factory *RST Set Diff

Auto channel configuration No (off) No effect ✓ Autozero On On Buffer No effect No effect

Auto clear Yes (on) No effect ✓

Channel Average Off Off Closed channels None None Closure count interval No effect No effect Continuity

Beeper On On Digits 4H digits 4H digits Range 1kΩ 1kΩ Rate Fast (0.1 PLC) Fast (0.1 PLC) Threshold level 10Ω 10Ω

Current (AC and DC)

Bandwidth (AC) 30 30 Digits (AC) 5H digits 5H digits Digits (DC) 6H digits 6H digits Filter On Off ✓

Window 0.1% 0.1% Count 10 10 Type Moving Repeat ✓

Range Auto Auto Rate (DC) Slow (5 PLC) Slow (5 PLC)

Rel Off Off Dry circuit ohms Off Off Frequency and Period

Digits 6H digits 6H digits

Range 10V 10V

Rate (aperture) 1 second 1 second

Rel Off Off Function DCV GPIB No effect No effect

Address No effect (16 at factory) No effect (16 at factory) Keyclick On On

1-22 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Table 1-4 (continued)

Default settings

Setting Factory *RST Set Diff

Limits Off Off

LO Limit 1 -1 -1 HI Limit 1 +1 +1 LO Limit 2 -2 -2

HI Limit 2 +2 +2 Line Synchronization Off Off Math

mX+B Off Off

Scale Factor 1.0 1.0 Offset 0.0 0.0 Units “X” “X”

Percent Off Off

Reference 1.0 1.0

1/X (Reciprocal) Off Off Monitor Off Off Output

Beeper Never Never

Digital Output Off Off

Logic Sense High High

Pulse No (off) No (off) Ratio Off Off Resistance (Ω2 and Ω4)

Digits 6H digits 6H digits

Filter On Off ✓

Window 0.1% 0.1% Count 10 10 Type Moving Repeat ✓

Offset compensation (OCOMP) Off Off

Dry circuit Off Off

Range Auto Auto

Rate Slow (5 PLC) Slow (5 PLC)

Rel Off Off

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-23

Table 1-4 (continued)

Default settings

Setting Factory *RST Set Diff

RS-232 Off Off

Baud rate No effect No effect Flow control XonXoFF XonXoFF Terminator No effect No effect

Scanning Disabled Disabled

Auto scan No (off) No effect ✓ Type (Simple or Advanced) No effect No effect Simple scan

Minimum channel 101, 201, 301, 401, or 501 101, 201, 301, 401, or 501 Maximum channel No effect No effect Timer Off Off Reading count No effect No effect

Advanced scan

Setup No effect No effect Immediate trigger On On

Limit triggers Off Off Timer Off Off Reading count No effect No effect

Temperature

Digits 5H digits 5H digits Filter On Off ✓

Window 0.1% 0.1% Count 10 10 Type Moving Repeat ✓

Rate Slow (5 PLC) Slow (5 PLC) Rel Off Off Sensor Thermocouple Thermocouple

Junction See Note See Note Open detector No (off) No (off) Type K K Units °C °C

Timestamp No effect No effect Triggering Continuous One-shot ✓

Delay Auto Auto Source Immediate Immediate

1-24 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Table 1-4 (continued)

Default settings

Setting Factory *RST Set Diff

Voltage (AC and DC)

dB Off Off

Reference 1.0 1.0 Digits (AC) 5H digits 5H digits Digits (DC) 6H digits 6H digits Filter On Off ✓

Window 0.1% 0.1%

Count 10 10

Type Moving Repeat ✓ Range Auto Auto Rate (DC) Slow (5 PLC) Slow (5 PLC) Rel Off Off

Note: With a Model 7700, 7706, or 7708 installed, the default sensor junction is Internal. Otherwise, the Simulated (23ºC) junction is

selected.

Remote progr amming — default and user setups

Default and user setup commands are listed in Table 1-5.

NOTE The SYSTem:PRESet and *RST defaul ts are listed in the SCPI tables in

Section 15.

Table 1-5

Default setup commands

Commands Description

SYSTem:PRESet Restore SYSTem:PRESet defaults. *RST Restore *RST defaults.

*SAV <NRf> Save settings as user-setup; <NRf> = 0, 1 or 2. *RCL <NRf> Restore user-saved setup; <NRf> = 0, 1 or 2.

SYSTem:POSetup <name> Specify power-on setup; <name> = RST , PRESet, SAV0,

SAV1, or SAV2.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-25

Programming e xample

*SAV 2 ' Save present setup in memory location 2. SYST:POS SAV2 ' Specify SAV2 setup as the power-on setup. *RST ' Return 2750 to RST defaults. *RCL 2 ' Return 2750 to setup stored in memory location 2.

Remote progr amming information

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

NOTE Except for Section 11 through Section 15, most programming tables in th is man-

ual are abridged. That is, they e xclude 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, Model 2750 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 command is sent and Model 2750 is addressed to talk, the response message is sent to the computer.

NOTE For complete details, see “Programming syntax,” page 1 0-11 .

Quick start ex ercises

This section topic summarizes the following basic instrument operations and provides simple exercises to perform them:

• Basic DMM measurements — front panel inputs

• Closing and opening channels — system channel operation

• Simple scanning

• Trigger and return readings — remote programming

WARNING For the exercises, it is not necessary to connect an input signal or DUT

to the instrument (front panel inputs or switching module inputs). However, if you decide to use an input signal, it is recommended that you keep it at a nonhazardous level (<42V) while learning to use the instrument.

1-26 Getting Started Model 2750 Multimeter/Switch System User’s Manual

NOTE When using the front panel input terminals, the INPUT switch must be in the

“F” (out) position. The INPUT switch is located on the right side of the front panel near the input terminals. When using a switching module, the switch must be in the “R” (in) position.

Basic DMM measurements — front panel inputs

NOTE See Section 3 for details on basic DMM operation.

The Model 2750 is shipped from the factory to power-up to factory defaults. The instrument powers up to a setup that continuously measures DC volts. Some of the default settings for the DCV function include auto range enabled, 6½-digit resolution, filter enabled, and slow reading rate. These settings provide a good starting point and in many cases, do not need to be changed.

“Starting-point” default settings are also provided for the other measurement functions. Therefore, to perform basic measurements, simply select the desired function, and “tweak” the setup (range, rate, filter, digits, etc.) as required.

For remote programming, the instrument is typically used in a non-continuous measurement mode. In this mode, the user (via remote command programming) specifies the number of measurements to perform. *RST defaults place the instrument in a non-continuous measurement mode. Most of the other settings for factory and *RST defaults are the same.

For remote programming, the following command is used to select function.

NOTE Items in brackets ([]) are optional and do not need to be included. Upper case

characters are required. Lower case characters are optional and need not be included.

[SENSe[1]]:FUNCtion <func> ' Select measurement function.

<func> = 'VOLTage[:DC]' DCV

'VOLTage:AC' ACV 'CURRent[:DC]' DCI 'CURRent:AC' ACI 'RESistance' Ω2 'FRESistance' Ω4 'FREQuency' FREQ 'PERiod' PERIOD 'TEMPerature' TEMP

Each function can have its own unique setup configuration (i.e., range, digits, speed, etc.). For example, the following command words select range and digits:

RANGe[:UPPer] <n> ' Specify expected reading. RANGe:AUTO ' Enable (ON) or disable (OFF) auto range. DIGits ' Set display resolution; 3.5, 4.5, 5.5 or 6.5 (digits).

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-27

The following examples demonstrate how to include the function name in the command string for configuration commands.

VOLT:RANG 10 ' Select 10V range for DCV. RES:RANG:AUTO ON ' Enable auto range for W2. CURR:DIG 4.5 ' Set DCI for 4½- digit resolution.

NOTE See Section 4 for details on setting range, digits, rate, bandwidth, and filter.

Exercise 1 — Basic DMM measur ements

The exercise in Table 1-6 measures ACV on the 10V range and stores 15 readings in the buffer.

Table 1-6

Exercise 1 — Measure AC volts - store readings in buffer

Front panel operation Command sequence

1 For front panel operation, proceed to step 2.

For remote programming, clear the buffer

TRAC:CLE

2 Restore defaults2:

Press SHIFT > press SETUP > select RESTORE: FACT.

*RST

3 Select ACV function:

Press ACV.

FUNC 'VOLT:AC'

4 Select 10V range:

Press RANGE

Δ to display “RANGE: 10V”.

VOLT:AC:RANG 10

6 Store 15 readings in buffer3:

Press STORE > set for 000015 RDGS > press ENTER.

SAMP:COUN 15

READ?

7 Recall buffer readings4:

Press RECALL > use edit keys to display readings. Press EXIT to exit

CALC1:DATA?

recall mode.

1. To a v o id problems with remote programming, it is good practice to routinely clear th e buffer (TRAC:CLE) at the beginning of a program that performs multiple measurements ( the buffer.

2. FACTory defaults place the instrument in a continuous measurement mode. *RST places the instrument in a noncontinuous measurement mode.

3. READ? triggers and returns 15 readings. These 15 readings are automatically stored in the buffer. See Exercise 4 and 5 for more information on the READ? command.

4. Statistics for buffer readings are also stored in the buffer. For remote programming, ings that were stored. It does not return buffer statistics. (see Section 6 for details).

SAMP:COUN >1). Restoring *RST or F ACTory defaults does not clear

CALC1:DATA? only returns the read-

CALC2 commands are used to calculate and return buffer statistics

1-28 Getting Started Model 2750 Multimeter/Switch System User’s Manual

DMM

DUT

DMM

Switching Module Switching Module

Input

Ch 1

Input

Ch 1

Closing and opening channels — system channel oper ation

NOTE See Section 2 for details on closing and opening switching module channels. NOTE The following discussion assumes a multiplexing switching module (i.e., Model

7700) installed in slot 1 of the mainframe. Switching module installation is covered in “Switching module installation and connections,” page 2-3.

An alternative to installing a switching module is to assign slot 1 as a pseudocard using remote programming. The instrument will operate as if a switching module is installed in slot 1. To “install” a 7700 pseudocar d in slot 1, send the following command:

SYST:PCAR1 C7700

System channel operation is used to connect input channels to the DMM of the Model 2750:

• For a 2-wire function (i.e., DCV), closing a system channel connects the input to DMM Input of the Model 2750.

Figure 1-5 shows system channel 1 closed. For the Ω2 function, the resistance

(DUT) would be connected to DMM Input as shown Figure 1-5.

• For a 4-wire function (i.e., Ω4), a channel pair is connected to the DMM when a system channel is closed. The system channel is connected to DMM Input and the paired channel is connected to DMM Sense.

Figure 1-6 shows system channel 6 closed. For a 4-wire function, the paired chan-

nel also closes. For the Model 7700, channels 1 through 10 are paired to channels 11 through 20. When channel 6 is closed, channel 16 also closes. Figure 1-6 shows how the DUT is connected to the DMM for the 4-wire function.

NOTE Figure 1-5 and Figure 1-6 show simplified schematics of the switching module.

They show a single switch closed to connect an input channel to the DMM. In reality, multiple switching to is used to make proper connections to the DMM. However, for system channel operation, the user need not be concerned about which switches in the module close.

Figure 1-5

Connection to DMM for 2-wire function (system channel 101 closed)

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-29

DUT

DMM DMM

7700

Switching Module

7700

Switching Module

Input

Ch 6

Sense

Ch 16

Input

Sense

Ch 16

Ch 6

Figure 1-6

Connectio n to DMM for 4-wire function (system channel 106 closed)

NOTE Switching module channels can also be contr olled using multiple channel opera-

tion. This allows individual control of all module channels (switches). Multiple channel operation should only be used by experienced service personnel who recognize the dangers associated with multiple channel closures. See Section 2 for details.

Close/open operation

The following points on operation pertain to system channel operation only:

• Only one input channel (or channel pair) is closed at one time. When you close an input channel, the previously closed input channel(s) will open.

• When a system channel is closed, the channel number will be displayed on the Model 2750. The slot number for the module is also displayed. For example, “103” indicates that system input channel 3 for a module in slot 1 is closed.

• The paired channel for a 4-wire function is not displayed. Only the system channel number is displayed. For example, in Figure 1-6, channel number 106 will be displayed with the Model 7707 installed in slot 1 of the mainframe.

• Switching modules that have current measurement capability have separate channels reserved exclusively for the DCI and ACI functions. For example, the Model 7700 has channels 21 and 22 reserved for amps measurements. With the DCI or ACI function selected, only channels 21 and 22 can be closed. These channels cannot be accessed on any other function.

Figure 1-7 shows the front panel keys used to close and open system channels.

1-30 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Close next

measurement

channel

Close previous

measurement

channel

CLOSEOPEN

CLOSE CH: XXX

CLOSE:SINGLE

Press CLOSE key

Display SINGLE option and press ENTER

Specify channel number (XXX) and press ENTER

CLOSEOPEN

OPEN: ALL

Press OPEN key

Display ALL option and press OPEN again

A. Sequencing through channnels B. Specifiying channel to close C. Opening all channels

Figure 1-7

Front panel keys to close and open system channels

For remote programming, the following three commands are used for basic system operation to open and close input channels:

ROUTe:CLOSe <clist> ' Close specified system channel1. ROUTe:CLOSe? ' Query closed system channel ROUT:OPEN:ALL ' Open all channels.

1. Only one channel can be specified in the <clist>. For example, to close input channel 3 for a module in slot 1, the following command would be sent:

ROUTe:CLOSe (@103)

2. Only the closed system channel is returned by ROUTe:CLOSe?. The paired channel for a 4-wire function is not returned. For example, assume channel 2 in slot 1 is closed. The following response message will be returned:

(@102)

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-31

Exercise 2 — Closing and opening c hannels (system channel oper ation)

The exercise in Table 1-7 demonstrates a sequence to close and open channels of a Model 7700 installed in slot 1 of the mainframe.

Table 1-7

Exercise 2 — Close and open channels (system channel operation)

Front panel operation Command sequence

1 Open all channels*:

Press OPEN > display OPEN:ALL > Press OPEN.

ROUT:OPEN:ALL

2 Select Ω2 function:

Press Ω2.

FUNC 'RES'

3 Close system channel 101:

Press the  key. Channel 1 connects to DMM Input (see Figure 1-5).

ROUT:CLOS (@101)

4 Close system channel 102:

Press the  key. Channel 2 connects to DMM Input.

ROUT:CLOS (@102)

5 Close system channel 106:

Press CLOSE > select CLOSE:SINGLE > key in channel 106 > press

ROUT:CLOS (@106)

ENTER. Channel 6 connects to DMM Input.

6 Select Ω4 function:

Press Ω4. 4W annunciator turns on, and channels 6 and 16 connects to

FUNC 'FRES'

DMM Input and Sense (see Figure 1-6).

7 Open all channels*:

Press OPEN > display OPEN:ALL > Press OPEN ROUT:OPEN:ALL

*It is a good, safe practice to start and end a switching sequence by opening all channels.

Simple scanning

NOTE See Section 7 for details on scanning.

With at least one multiplexer switching module (i.e., Model 7700) installed in the mainframe, the instrument can scan channels that are valid for the selected function.

For front panel operation, Figure 1-8 shows the three basic steps to configure and run a simple scan. The differences between the STEP function and the SCAN function involve the reading count and the timer.

Reading count (RDG CT) — For both STEP and SCAN, the reading count specifies the number of readings to store in the buffer . For STEP, the reading count determines the number of channels to scan.

For SCAN, the reading count also determines the number of scans to perform and is best explained by an example. Assume there are 10 channels in the scan list (i.e., 101 through

110). If you set the reading count to 10 or less, one scan of the 10 channels will be performed. If you set the reading count to any value from 11 to 20, two scans will be performed. A reading count from 21 to 30 gives you three scans, and so on.

1-32 Getting Started Model 2750 Multimeter/Switch System User’s Manual

MIN CHAN: XXX

INT: SIMPLE

Display SIMPLE option and press ENTER

Specify minimum channel (XXX) and press ENTER

SHIFT

SCANSTEP

CONFIG

Press SHIFT

Press CONFIG (STEP)

MAX CHAN: YYY

Specify maximum channel (YYY) and press ENTER

TIMER? NO/YES

Display NO or YES and press ENTER

YESNO

xxH:xxM:xx.xxxS

Set timer interval in hr:min:sec format and press ENTER

RDG CT:xxxxxx

Specify reading count and press ENTER

SCANSTEP

Press STEP or SCAN to start scan

Timer interval specifies time between scans.

Reading count: Specifies number of scans to be performed. Specifies number of readings to store in buffer.

Timer interval specifies time between scanned channels.

Reading count: Specifies number of channels to be scanned. Specifies number of readings to store in buffer.

Step 1. Configure simple scan: Step 2. Run simple scan:

SHIFT

SCANSTEP

HALT

Press SHIFT

Press HALT (SCAN)

Step 3. Disable scan mode:

Timer interval (TIMER) — For the STEP function, the timer specifies the time delay between scanned channels. For the SCAN function, the interval specifies the time delay between scans. The timer starts when the scan is started. For SCAN, the next scan will not start until the timer interval expires.

NOTE The Model 2750 can also be configured to run an advanced scan. For an

advanced scan, each channel can have its own unique setup (i.e., function, range, etc.). Advanced scanning is covered in Section 7.

Figure 1-8

Simple scan operation

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-33

For remote programming, the following commands are used for simple scanning:

ROUTe:SCAN <clist> ' Define scan list*. TRIGger:COUNt <NRf> ' Specify number of scans (1 to 11000 or

' INFinity).

SAMPle:COUNt <NRf> ' Specify number of channels to scan

ROUTe:SCAN:LSELect <name> ' Enable (INT) or disable (NONE) scan.

' (1 to 11000).

*Any valid switching module channel can be included in the scan list. Make sure to list

them from the lowest numbered channel to the highest. For example, to scan channels 1 through 8 of a Model 7700 installed in slot 1, send the following command to define the scan list:

ROUTe:SCAN (@101:108)

Exercise 3 — Simple scanning

The scanning example in Table 1-8 assumes a Model 7700 installed in slot 1 of the mainframe. The scan will use default settings (DCV) to scan eight channels and store the readings in the buffer.

Table 1-8

Exercise 3 — Simple scanning

Front panel operation Command sequence

1 For front panel operation, proceed to step 2.

For remote programming, clear the buffer:

TRAC:CLE

2 Restore defaults1:

Press SHIFT > press SETUP > select RESTORE: FACT.

*RST

3 Configure scan:

Press SHIFT > press CONFIG > select INT: SIMPLE > set MIN CHAN101 > set MAX CHAN: 108 > select TIMER? NO > set RDG

ROUT:SCAN (@101:108) SAMP:COUN 8

CT:000008.

4 Enable and start scan2:

Press STEP.

ROUT:SCAN:LSEL INT INIT

5 Halt (disable) scanner:

Press SHIFT > press HALT.

ROUT:SCAN:LSEL NONE

6 Recall the eight stored readings:

Press RECALL > use edit keys to display readings. Press EXIT to

CALC1:DATA?

exit recall mode.

7 Open all channels:

Press OPEN > display OPEN:ALL > Press OPEN

1. Factory and *RST defaults opens all channels, select the DCV function and sets TRIG:COUN to 1. The trigger count specifies the number of scans to be performed.

2. ROUT:SCAN:LSEL INT enables the scan, and INIT triggers the start of the scan.

ROUT:OPEN:ALL

1-34 Getting Started Model 2750 Multimeter/Switch System User’s Manual

T rigger and return readings — r emote progr amming

There are several commands used to trigger and return readings. The proper commands and sequence to use depend on trigger state (continuous or non-continuous) and what you are trying to accomplish.

Presented here are three fundamental command sequences that can be used to “trigger and return readings.” These three command sequences (exercises) will accommodate most basic measurement scenarios. Simply use the command sequence (exercise) that satisfies your needs:

• Exercise 4 — Trigger and return a single reading

• Exercise 5 — Trigger and return multiple readings

• Exercise 6 — Return a single reading (continuous triggering)

Details on the commands to trigger and return readings are provided in other sections of this manual. For details, refer to the following sections:

Section 3 — See “Trigger and retrieve readings” in Table 3-8. Section 7 — For scanning, see “Trigger commands” in Table 7-1. Section 8 — Explains the triggering process. Section 13 — Covers Signal Oriented Measurement Commands (i.e., FETCh?, READ?). Section 15 — See Table 15-9 (Trigger command summary). Appendix D — Shows how trigger and read commands control data flow within the

instrument.

NOTE Each exercise indicates the commands used to configure triggering. Once

triggering is configured, the commands to trigger and/or return readings can be repeated as often as desired (unless noted otherwise).

Exercise 4 — Trigger and return a single reading Exercise 5 — Trigger and return multiple readings

Trigger controlled measurements — The instrument is typically used in a non-continuous trigger mode. In this mode, commands are used to trigger one or more readings. After the specified number of readings are completed, the measurement process stops.

Exercise 4 in Figure 1-9 provides a command sequence to trigger and return one reading. Exercise 5 in Figure 1-10 provides a command sequence to trigger and return multiple readings.

Exercise 6 — Return a single reading (continuous triggering)

Readings can be returned while the instrument is in the continuous measurement (trigger) mode. Each time a read command is sent, the latest reading is returned. Exercise 6 in

Figure 1-11 provides a command sequence to return a single reading while in the continu-

ous trigger state.

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-35

INIT:CONT OFF

TRIG:COUN 1

SAMP:COUN 1

Place 2750 in non-continuous trigger state

Set 2750 to perform one measurement

1. If a MATH function (mX+B, percent or 1/X) is enabled, the result of the calculation will be returned (MATH functions are covered in Section 5).

3. FETCh?, CALC:DATA?, and DATA? do not trigger readings. They simply return the last reading. If you again send one of these commands before triggering a new reading, the old reading will be returned.

Return Basic Reading

3,4

INITTrigger Reading

READ?

2. If there is no MATH function enabled,

FETCh?and CALC:DATA? will return the basic

reading.

Trigger and Return Reading

Trigger Configuration

Trigger and Return

Reading

DATA?

DATA:FRESh?

Return Result of MATH Calculation

1, 2, 3

4. DATA:FRESh? can only be used once to return the same reading. Sending it again without first triggering a new reading will cause error -230 (data corrupt or stale).

FETCh?

CALC:DATA?

Figure 1-9

Exercise 4 — Trigger and return a single reading

1-36 Getting Started Model 2750 Multimeter/Switch System User’s Manual

INIT:CONT OFF TRIG:COUN 1

SAMP:COUN x

READ?

INIT FETCh?

Place 2750 in non-continuous trigger state

Set 2750 to perform “x” number of measurements (x = 2 to 110000)

2. INIT triggers the measurements, and FETCh? returns the readings. Again sending FETCh? without first sending INIT will return old readings.

4. Triggered readings are automatically stored in the buffer. Statistics for buffer readings are also stored in the buffer. CALC2 commands are used to calculate and return buffer statistics (see Section 6 for details).

TRAC:CLE

Clear Buffer

Trigger and Return Readings

2, 3

3. READ? performs an INIT to trigger the measurements, and then FETCh? to return the reading(s).

TRAC:DATA?

Return Stored Readings

Trigger and Return

Readings

Trigger Configuration

1. In order to trigger and return multiple readings, the buffer must first be cleared of readings that were stored by the TRACe command or front panel operation (see Section 6 for details on buffer operation).

Figure 1-10

Exercise 5 — Trigger and return multiple readings

Model 2750 Multimeter/Switch System User’s Manual Getting Started 1-37

SAMP:COUN 1 INIT:CONT ON

DATA?

DATA:FRESh?

FETCh?

CALC:DATA?

Place 2750 in continuous trigger state.

Return Basic Reading

2, 3

Return result of MATH Calculation

1, 2

1. If a MATH function (mX+B, percent or 1/X) is enabled, the result of the calculation will be returned.

If there is no MATH function enabled, FETCh? and CALC:DATA? will return

the basic reading.

MATH functions are covered in Section 5.

2. None of these read commands trigger measurements. They simply return the lastest reading. If FETCH?, CALC:DATA?, or DATA? is again sent before a new reading is triggered, the ld reading will be returned.

3. DATA:FRESh? can only be used once to return the same reading. Sending it again before

a new reading is triggered will cause error -230 (data corrupt or stale).

Return Readings

Trigger Configuration

Figure 1-11

Exercise 6 — Return a single reading (continuous triggering)

1-38 Getting Started Model 2750 Multimeter/Switch System User’s Manual

Closing and Opening

SwitchingModuleChannels

• Close/open overview — Summarizes the two operating modes to control switch-

ing modules: system channel operation and multiple channel operation.

• Switching module installation and connections — Explains how to install a

switching module (or pseudocard) into the Model 2750 mainframe. Also explains where to find connection information which should only be performed by qualified service personnel.

• Channel assignments — Explains the format for specifying the mainframe chan-

nel assignment which is made up of the slot number and switching module channel number.

• System channel operation — Provides detailed information for using system

channel operation.

• Multiple channel operation — Provides detailed information for using multiple

channel operation. Due to safety considerations, this operating mode should only be used by experienced test engineers.

• Identifying installed modules and viewing closed channels — Explains how to

use the CARD menu to identify installed switching modules and view closed channels. Explains how to remotely identify installed modules (*OPT?) and summarizes other query commands that can be used to acquire information about the installed modules.

• Relay closure count — Explains how to determine the number of times switching

module relays have been closed.

• Model 7700 switching module — Covers operating characteristics that are unique

to the Model 7700. Also includes a simplified schematic diagram of the switching module.

2-2 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Close/open ov erview

NOTE This section covers basic close/open operations for switching module channels.

It also covers the operating characteristics that are unique to the Model 7700 switching module. Unique operating characteristics for all switching modules are provided in the Model 77XX Series Switching Modules Instruction Manual.

There are two modes of close/open operation:

• System channel operation — This is the mode of operation that should be used

exclusively by most (if not all) users. When you close an input channel (or channelpair), other channels on the switching module close automatically to internally connect it the DMM of the Model 2750.

• Multiple channel operation — This mode of operation provides additional flexi-

bility by providing individual control of each switching module channel. Ho wever , careless operation could create a safety hazard and/or damage the switching module and other equipment. Multiple channel operation should only be used by experienced test engineers.

CAUTION T o prevent damage to a switching module, do not exceed the maximum

signal level input for that module. Most switching modul es are rated for 303V. The following command queries maximum module voltage:

SYSTem:CARDx:VMAX? ‘ Request maximum allowable voltage for

‘ CARDx (where x is the slot number for ‘ the module).

For system channel operation, the instrument will display the “OVERFLOW” message when the maximum allowable voltage for the module is being exceeded.

However, for multiple channel operation, the “OVERFLOW” message will not occur until the maximum voltage of the mainframe (not module) is exceeded. Therefore, the “OVERFLOW” message would occur only if 1010V is exceeded.

WARNING Careless multiple channel operation could create an electric shock haz-

ard that could result in severe injury or death. Improper operation can also cause damage to the switching modules and external circuitry. Multiple channel operation should be restricted to experienced test engineers who recognize the dangers associated with multiple channel closures.

NOTE The Model 2750 can scan switching module channels. Each channel in the scan

can have its own unique setup configuration. Scanning is covered in Section 7.

NOTE When a setup is saved as a user setup (SAV0, SAV1, or SAV2), closed channels

are also saved. When the setup is restored, those channels (and only those channels) will be closed (see “Defaults and user setups,” page 1-19).

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-3

Switching module installation and connections

In order to exercise close/open operations explained in this section, a switching module (or pseudocard) must be installed in the mainframe. A switching module can be installed by the user, however external connections to the switching module are only to be performed by qualified service personnel.

NOTE For inexperienced users, it is recommended that DUT and external circuitry not

be connected to switching modules. This will allow you to exercise close/open operations without the dangers associated with live test circuits.

WARNING To prevent electric shock that could result in injury or death, NEVER

handle a switching module that has power applied to it:

• Before installing (or removing) a switching module, make sure the Model 2750 is turned off and disconnected from line power.

• If the switching module is already connected to DUT, make sure power is removed from all external circuitry.

Module installation

WARNING Slot covers must be installed on unused slots to prevent personal con-

tact with high voltage circuits.

Perform the following steps to install a switching module into the Model 2750 mainframe:

1. Turn the Model 2750 off and disconnect the power line cord and any other cable connected to the rear panel.

2. Position the Model 2750 so you are facing the rear panel.

3. Remove the slot cover plate from the desired mainframe slot. Retain the plate and screws for future use.

4. With the top cover of the switching module facing up, slide the module into an empty slot. For the last G inch or so, press in firmly to mate the module connector to the mainframe connector.

5. On each side of the module, there is a mounting screw. Tighten these two sc re ws to secure the module to the mainframe. Do not overtighten.

6. Reconnect the power line cable and any other cables to the rear panel.

7. When you turn on the Model 2750, the model number of the switching module will be briefly displayed.

2-4 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Connections

WARNING Connection information for switching modules is in ten ded for quali-

fied service personnel. Do not attempt to connect DUT or external circuitry to a switching module unless qualified to do so.

To prevent electric shock that could result in serious injury or death, adhere to following safety precautions:

• Before making or breaking connections to the switching module, make sure the Model 2750 is turned off and power is removed from all external circuitry.

• Do not connect signals that will exceed the maximum specifications of switching module.

If both the front panel terminals and the switching module terminals are connected at the same time, the test lead insulation must be rated to the highest voltage that is connected. For example, if 1000V is connected to the front panel input, the test lead insulation for the switching module must also be rated for 1000V.

Dangerous arcs of an explosive nature in a high energy circuit can cause severe personal injury or death. If the multimeter is connected to a high energy circuit when set to a current range, low resistance range, or any other low impedance range, the circuit is virtually short ed. Dangerous arcing can result even when the multimeter is set to a voltage range if the minimum voltage spacing is reduced in the external connections. For details to safely make high energy measurements, see

“High energy circuit safety precautions,” page 3-3.

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, the Model 2750 is Installation Category I and must not be connected to mains.

For the Model 7700, detailed connection and wiring information is provided in

Appendix B of this manual (Model 7700 Connection Guide).

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-5

Pseudocards

Using remote programming, you can assign a pseudocard to an empty switching module slot. With a pseudocard installed, the Model 2750 will operate as if the switching module is installed in the Model 2750. This feature allows you exercise open/close/scan operations, or configure your system without having the actual switching module installed in the unit. There is a pseudocard for every Keithley Model 77XX series switching module.

A pseudocard cannot be installed from the front panel. However, once it is installed, you can take the Model 2750 out of remote and use the front panel. Pressing the LOCAL key takes the Model 2750 out of remote.

When a pseudocard is installed, the appropriate front panel slot indicator lamp turns on. When the instrument is turned off, the pseudocard will be lost (uninstalled). Use the following commands to install pseudocards:

SYSTem:PCARd1 <name> ' Install pseudocard in slot 1. SYSTem:PCARd2 <name> ' Install pseudocard in slot 2. SYSTem:PCARd3 <name> ' Install pseudocard in slot 3. SYSTem:PCARd4 <name> ' Install pseudocard in slot 4. SYSTem:PCARd5 <name> ' Install pseudocard in slot 5. <name> = C7700, C7701, C7702, C7703, C7705, C7706, C7707, C7708 or C7709

Programming example — The following command sets up the Model 2750 to operate as if a Model 7700 switching module is installed in slot 2, which must be empty. You cannot assign a pseudocard to a slot that already has a switching module installed in it.

SYSTem:PCAR2 C7700 ' "Install" pseudocard 7700 for slot 2.

Channel assignments

The Model 2750 has five slots for switching modules. T o control the appropriate switching module, the slot number must be included with the switching module channel number when you specify a channel. The channel assignment is formatted as follows:

SCH where: S is the slot number

CH is the channel number Examples: 101 = Slot 1, Channel 1

210 = Slot 2, Channel 10 506 = Slot 5, Channel 6

NOTE For remote operation, the 3-digit channel assignment is included in the channel

list parameter for the commands. Format examples for the channel list parameter are provided in Table 2-1 and Table 2-2.

2-6 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

System channel oper ation

The system channel is a closed measurement channel that is internally connected to the internal DMM Input of the Model 2750. The system channel number is displayed on the Model 2750. For a 4-wire function (i.e., Ω4), the paired channel for the system channel is internally connected to DMM Sense. The paired channel is not displayed on the Model

2750. When triggered, the DMM performs a measurement and displays it on the Model

2750. The system channel is selected by closing a measurement channel using the system chan-

nel close keys. These include the  and  keys, or the CLOSE key (SINGLE menu option). See “Controlling the system channel,” page 2-9, for details.

Other important points about system channel operation include the following:

• There can only be one system channel. This is the channel that is presently displayed (and closed) on the Model 2750. When a channel is not displayed, there is no system channel.

• When a measurement channel is closed, the input backplane isolation channel also closes to connect the system channel to DMM input. For a 4-wire function, the paired channel and the sense backplane isolation channel also close to make the sense connections to the DMM.

• When a different measurement channel is closed, the previous system channel opens. The newly closed (and displayed) measurement channel becomes the system channel.

• The system channel close keys can only close measurement channels that will automatically connect to the DMM. Non-measurement channels cannot be closed by the system channel close keys.

NOTE Use the VIEW option of the CARD menu to display all closed channels in the

mainframe (see “CARD menu,” page 2-28).

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-7

DMM

Model 7700 Switching Module

Model 2750

Slot 1

System Channel Operation: Close Channel 101

Channel 1

Relay

Input

Channel 25

Backplane

Isolation

Relay

Channel 1

2-wire functions

Figure 2-1 shows an example of how the system channel is connected to the DMM Input

of the Model 2750. Assume a Model 7700 switching module is installed in slot 1 of the mainframe. When channel 101 is closed using the system channel close keys, both the Channel 1 relay and the backplane isolation relay (Channel 25) closes to connect the channel to the DMM. The complete simplified schematic of the Model 7700 is provided in

Figure 2-12.

Figure 2-1

2-wire system channel connections to Model 2750 DMM

4-wire functions (paired channels)

A 4-wire function, such as Ω4, requires that another measurement channel be paired to the system channel. For example, if the switching module has 20 measurement channels, channels 1 through 10 can be used as the system channel, while channels 11 through 20 are used as the paired channel. For a switching module that has 20 measurement channels, channel 1 is paired to channel 11, channel 2 is paired to channel 12, channel 3 is paired to channel 13, and so on.

Figure 2-2 shows an example of system channel connections for a 4-wire function.

Assume a Model 7700 switching module is installed in slot 1 of the mainframe, and a 4wire function, such as Ω4, is selected. When channel 101 is closed using the system chan- nel close keys, the Channel 1 relay and the input backplane isolation relay (Channel 25) closes to connect the channel to DMM Input. Also, the Channel 11 relay and the sense backplane isolation relay (Channel 24) closes to connect the paired channel to DMM Sense. Also note in Figure 2-2 that the Channel 23 rela y closes to isolate channel 1 from channel 11.

The complete simplified schematic of Model 7700 is provided in Figure 2-12.

2-8 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

DMM

Model 7700 Switching Module

Model 2750

Slot 1

Close Channel 101

System Channel Operation:

(Closed Position

Shown

)

Channel 1

Relay

Input

Channel 25

Backplane

Isolation

Relay

Channel 1

Channel 11

Relay

Sense

Channel 24

Backplane

Isolation

Relay

Channel 11

Channel

2-Pole/4-Pole

Relay

Figure 2-2

4-wire system channel connections to Model 2750 DMM

Controlling the system channel

When a measurement channel is closed, a previous system channel (and, for a 4-wire function, its paired channel) is first opened. The closed measurement channel becomes the system channel. When a 4-wire function is selected, the paired channel for the system channel also closes.



and  keys

These front panel keys (Figure 2-3) can be used to select the next or previous measurement channel as the system channel. If there are no measurement channels available, one of the following messages will be briefly displayed when one of these keys is pressed:

NO SCAN CARD — This message indicates that there are no switching modules (or pseudocards) installed. All five slots are empty.

NO MEAS CARD — This message indicates that none of the installed switching modules (or pseudocards) have measurement channels. For example, the Model 7705 switching module does not have any measurement channels. Those channels cannot be internally connected to the DMM.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-9

Close next

measurement

channel

Close previous

measurement

channel

NOTE The  and  keys can also be used to open all c hannels in the mainframe. Sim-

ply increment or decrement the channel number until there is no channel displayed.

Figure 2-3

System channel operation — closing next or previous measurement channel

CLOSE key (SINGLE menu option)

The SINGLE menu option for the CLOSE key can be used to select a measurement channel as the system channel (Figure 2-4). Perform the following steps to select the system channel:

1. Press the CLOSE key. The message “CLOSE:SINGLE” message will be displayed.

NOTE If the “CLOSE:MULTI” message is instead displayed when CLOSE is pressed,

it indicates that there are no measurement modules installed in the mainframe. See “Multiple channel operation,” page 2-15, to close the channels of a non- measurement module (i.e., Model 7705).

2. Press ENTER to display the prompt to close a channel (CLOSE CH: XXX).

3. Using , ,

Δ , and ∇, key in the three-digit channel you want to select.

4. Press ENTER. The channel closes and the CHAN annunciator turns on.

An inv alid channel cannot be closed and will cause one of the following error messages to be briefly displayed:

INVALID CHAN — This message indicates that the channel is not a valid measurement channel. The following actions will cause this error:

• Trying to close a non-measurement channel, such as a backplane isolation channel, a channel that sets the pole mode, or a channel that cannot be internally connected to the DMM.

• Trying to close an amps channel while on a non-amps function. The DCI or ACI function must be selected in order to close an amps channel.

• Trying to close a paired-channel while on a 4-wire function. For the Model 7700, channels 1 through 10 are paired to channels 11 through 20 for a 4-wire function. If, for example, you try to close channel 12 while on the Ω4 function, the INVALID CHAN error will occur.

• Trying to close a switching module channel that does not exist.

2-10 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

CLOSEOPEN

CLOSE CH: XXX

CLOSE:SINGLE

Press CLOSE key

Display SINGLE option and press ENTER

Specify channel number (XXX) and press ENTER

OPEN

OPEN: ALL

Press OPEN key

Display ALL option and press OPEN again

TOO SMALL or TOO LARGE — These messages also indicate an invalid channel. TOO SMALL indicates that the specified channel and any other lower numbered channel is invalid. TOO LARGE indicates that the specified channel and any other higher numbered channel is invalid.

Figure 2-4

System channel operation — specifying measurement channel to close

OPEN key (ALL menu option)

The ALL menu option of the OPEN key opens all channels for all switching modules installed in the Model 2750 (Figure 2-5). For example, if a Model 7700 switching module is installed in slot 1, OPEN: ALL will open all measurement channels (101 to 120, 121, and 122), the backplane isolation channels (124 and 125) and the 2-pole/4-pole channel (123). Figure 2-2 shows the backplane isolation channels and the 2-pole/4-pole channel for the Model 7700.

Perform the following steps to open all channels:

1. Press the OPEN key to display “OPEN: ALL.”

2. Press OPEN a second time (or press ENTER) to open all channels.

NOTE Opening the system channel disables Ratio or Channel Average. Ratio and

Channel Average operation are covered in Section 5.

Figure 2-5

System channel operation — opening all channels in mainframe

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-11

Remote programming — system channel contr ol commands

The commands to close and open the system channel are listed in Table 2-1. When a system channel reading is returned, the system channel number will be included in the data string if the CHANnel data element is selected. The FORMat:ELEMents command is used to specify the data elements to be included in the data string (see FORMat commands in

Section 14).

Table 2-1

System channel control commands

Commands Description Ref

ROUTe:CLOSe <clist> Specify one measurement channel to close. a ROUTe:CLOSe:STATe? <clist> Query closed channels in specified list

(1 = closed).

ROUTe:CLOSe? Returns a <clist> of closed measurement

channels.

ROUTe:OPEN:ALL Open all channels, and disable ratio and channel

average.

Channel list parameter:

<clist> = (@SCH)

where: S = Mainframe slot number (1, 2, 3, 4 or 5)

CH = Switching module channel number (must be 2 digits)

Examples: (@101) = Slot 1, Channel 1

(@101, 203) = Slot 1, Channel 1 and Slot 2, Channel 3 (@101:110) = Slot 1, Channels 1 through 10

Reference:

a. ROUTe:CLOSe <clist>

This command functions the same as the front panel CLOSE key (SINGLE menu option) to select the system channel. Only one measurement channel can be specified in the <clist>.

Trying to close an invalid channel (such as a non-measurement channel) with this command will result in error -222 (Parameter data out of range).

b. ROUTe:CLOSe:STATe? <clist>

This query returns a “0” (open) or “1” (closed) for every measurement channel specified the <clist>. For example, assume <clist> = (@101, 104, 107, 102). The response message “0, 0, 1, 0” indicates that channel 107 is closed.

The state of non-measurement channels cannot be checked with this command.

2-12 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

c. ROUTe:CLOSe?

This query command returns a <clist> of closed measurement channels, including paired channels for 4-wire functions.

This query command will not return non-measurement channels, such as backplane isolation channels and the pole-mode channel.

d. ROUTe:OPEN:ALL

This command functions the same as the front panel OPEN key (ALL menu option). It simply opens all channels (including non-measurement channels) installed in the mainframe.

Remote programming example (system channel operation)

The following example assumes a Model 7700 installed in slot 1, and the Ω4 function of the Model 2750 is selected. This command sequence connects channel 101 and its paired channel (111) to DMM Input and Sense as shown in Figure 2-2.

ROUT:OPEN:ALL ' Open all channels. ROUT:CLOS (@101) ' Close channels 101, 111, 123,

' 124 and 125.

Non-amp and non-measure switching modules

There are Keithley switching modules that do not support current measurements and there are modules that do not support any measurements at all.

Non-amps module — With an amps function selected (DCI or ACI), system channel operation cannot be used to close channels on that module.

Non-measure module — For front panel oper at ion, system channel operation cannot be used to close channels. For remote programming, system channel operation can be used, but only the one specified channel will close. All other channels on the module will open.

Non-amps switching modules

NOTE Presently, non-amps Keithley modu les inclu de the Mo dels 7701, 7703, 7706,

7707, 7708, and 7709. You can check the Keithley website (www.keithley.com) for new modules.

A non-amp module does not support amps measurements. System channel operation cannot be used to close channels while an amps function (DCI or ICI) is selected.

If an amps function (DCI or ACI) is selected and you attempt to close a system channel, the message “NO AMPS CHAN” will be displayed briefly. For remote programming, error -222 (Parameter data out of range) is generated. Example:

SYST:PRES ' Restores system preset defaults. SENS:FUNC ‘CURR:DC’ ' Selects DCI function. ROUT:CLOS (@101) ' Attempts to close system channel 101 – Generates

' error -222.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-13

If a system channel is already closed and you attempt to select the DCI or ACI function, the message “INVALID FUNC” will be displayed briefly. For remote programming, error -221 (Settings conflict) is generated. Example:

SYST:PRES ' Restores system preset defaults. ROUT:CLOS (@101) ' Close system channel 101. SENS:FUNC ‘CURR:DC’ ' Attempts to select DCI function – Generates

' error -221.

2-14 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Making amps measurements — In order to perform amps measurements, you must use the front panel inputs of the 2701 mainframe. You can still use the non-amps module for other aspects of the test, but you must use multiple channel operation to close channels. Example:

NOTE In order to use the front panel inputs, make sure the INPUT switch is in the out

(F) position.

SYST:PRES ' Restores system preset defaults. ROUT:MULT:CLOS (@101) ' Closes channel 101. SENS:FUNC ‘CURR:DC’ ' Selects DCI function – Legal operation.

Non-measure switching modules

NOTE Presently, non-measure Keithley modules include the Models 7705, 7711, and

7712. You can check the Keithley website (www.keithley.com) for new modules.

Keep the following in mind when using a non-measure module:

• For a non-measure card, no channels are connected to the internal DMM (the channels cannot be connected to the backplane).

• Multiple channel operation should be used to close channels on a non-measure module. For remote operation, the ROUT:MULT commands are used to close channels.

• Front panel system (single) channel operation cannot be used to close channels on a non-measure module. For front panel operation, system channel operation will cause message “NO MEAS CARD” to be displayed.

• A non-measure module may have open/close operations that are specific only to that module. Refer to the appropriate module manual (packing list) for details on operation.

• In order to perform measurements, you must use the front panel inputs of the 2701 mainframe. You can still use the non-measure module to control other operations.

Multiple channel oper ation

The capability to individually control channels provides you with added flexibility in how you use a switching module. For example, assume you want to route a signal into channel 1 and out channel 20 of a Model 7700 switching module. You would do this by closing channels 1, 20, and 23. If you open channels 24 and 25, you will isolate the input signal from the DMM of Model 2750.

Multiple channel operation allows any channel (or channels) in the test system to be closed or opened. It allows more than one measurement channel to be closed at the same time. It also allows individual control of non-measurement channels, such as backplane

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-15

isolation channels. Multiple channel operation should only be performed by experienced test system engineers.

WARNING Careless multiple channel operation could create an electric shock haz-

NOTE Multiple channel operation cannot be used to perform thermocouple tempera-

ture measurements using the internal or external reference junction. The simulated reference junction will instead be used and the integrity of the temperature reading will be questionable (“ERR” annunciator turns on). See “Temperature

measurements ,” page 3-25, for details.

2-16 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Some other key points for multiple channel operation include the following:

• Closing a channel using multiple channel operation has no affect on other closed channels. Whatever channels were previously closed, remain closed.

• A channel closed using multiple channel operation is not displayed on the Model

2750. Also, the CHAN annunciator does not turn on when a channel is closed.

• Opening a channel using multiple channel operation has no affect on other closed channels. Only the specified channel opens.

NOTE Use the VIEW option of the CARD menu to display closed channels (see “CARD

menu,” page 2-28).

Controlling multiple channels

WARNING When using multiple channel operation, you must be very careful

when switching hazardous voltages. If you inadvertently close the wrong channel(s), you could create a shock hazard and/or cause damage to the equipment.

Most switching modules use latching relays. That is, closed channels remain closed when the Model 2750 is turned off. Never handle a switching module that is connected to an external source that is turned on. Turn off all power sources before (1) making or breaking connections to the module, and (2) installin g (or removing) the module into (or out of) the Model 2750.

Avoiding corrupt measurements

Aside from the safety issues, improper use of multiple channel operation can result in corrupt measurements. For example, assume two Model 7700s installed in slots 1 and 2, and a 2-wire function selected. If you use multiple channel operation to close channels 201 and 225, you will connect the input at channel 201 to the DMM for measurement.

If you then use system channel operation to close channel 101, channel 125 will also close to connect the input at channel 101 to the DMM. You now have two input channels (101 and 201) connected to DMM Input at the same time, inviting all sorts of problems.

The above problem can be avoided by opening channels 201 and/or 225 before closing channel 101 (and 125) as demonstrated by the following sequence:

1. Multiple channel operation — Close channels 201 and 225 for connection to DMM.

2. Multiple channel operation — Open channels 201 and/or 225 to disconnect from DMM.

3. System channel operation — Close system channel 101 to connect to DMM.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-17

CLOSEOPEN

CLOSE MLT:XXX

CLOSE:MULTI

Press CLOSE key

Display MULTI option and press ENTER

Specify channel number (XXX) and press ENTER

CLOSE key (MUL TI menu option)

The MULTI menu option for the CLOSE key can be used to close any individual channel in the mainframe (Figure 2-6). Perform the following steps to close a channel:

NOTE Channels closed by the MULTI option of the CLOSE key are not displayed. Use

the VIEW option of the CARD menu to display closed channels (see “CARD

menu,” page 2-28).

1. Press the CLOSE key and then use the “CLOSE:MULTI” message.

2. Press ENTER to display the prompt to close a channel (CLOSE MLT:XXX).

3. Using , ,

4. Press ENTER to close the channel.

An invalid channel cannot be closed. The error messages associated with system channel operation also apply to multiple channel operation.

Figure 2-6

Multiple channel operation — specifying a channel to close

Δ , and ∇, key in the three-digit channel you want to select.

Δ or ∇ key to display the

OPEN key

The OPEN key has two options to open channels: ALL and MULTI. The ALL option simply opens all channels in the mainframe. The MULTI option opens only the specified channel. All other closed channels remain closed. Figure 2-7 summarizes OPEN key operation.

OPEN: ALL — Perform the following steps to open all channels in the mainframe:

OPEN: MULTI — Perform the following steps to open only the specified channel:

1. Press the OPEN key to display “OPEN: ALL.”

2. Press OPEN again (or press ENTER) to open all channels.

1. Press the OPEN key. The “OPEN: ALL” message will be displayed.

2. Press the

Δ or ∇ key to display the “OPEN: MULTI” message.

2-18 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

CLOSEOPEN

OPEN: MULTI

Press OPEN key

Display MULTI option and press ENTER

OPEN: ALL

OPEN MULTI:XXX

Display ALL option and press OPEN again

Specify channel number (XXX) and press ENTER

3. Press ENTER to display the prompt to open a channel (OPEN MLT:XXX).

4. Using , ,

Δ , and ∇, key in the three-digit channel you want to select.

5. Press ENTER to open the channel.

NOTE If the channel you open using OPEN: MULTI is the system channel (channel

number displayed on the Model 2750), the channel will open, but the system channel number will still be displayed (see “Multiple channel operation

anomalies,” page 2-21).

Figure 2-7

Multiple channel operation — opening one or all channels

Remote programming — Multiple channel contr ol commands

The commands to close and open the system channel are listed in Table 2-2.

Table 2-2

Multiple channel control commands

Commands Description Ref

ROUTe:MULTiple:CLOSe <clist> Specify one or more channels to

close.

ROUTe:MULTiple:OPEN <clist> Open channels specified in list. Unlisted

channels not affected. ROUTe:OPEN:ALL Open all channels. c ROUTe:MULTiple:CLOSe? Returns a <clist> of all closed channels. d ROUTe:MULTiple:CLOSe:STATe?

<clist>

Channel list parameter:

<clist> = (@SCH)

where: S = Mainframe slot number (1, 2, 3, 4 or 5)

CH = Switching module channel number (must be 2 digits)

Examples: (@101) = Slot 1, Channel 1

(@101, 203) = Slot 1, Channel 1 and Slot 2, Channel 3 (@101:110) = Slot 1, Channels 1 through 10

Query closed channels in specified list

(1 = closed).

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-19

Reference:

a. ROUTe:MULTiple:CLOSe <clist>

This command functions like the front panel CLOSE key (MULTI menu option) to close channels. When you send this command to close the channels specified in the <clist>, only those listed channels will close. Channels not specified are not affected, and channel pairing is disabled.

NOTES Channels closed by ROUT:MULT:CLOS are not displayed.

The ROUT:MULT:CLOS command cannot be used to perform thermocouple temperature measurements using the internal or external reference junction. The simulated reference junction will instead be used and the integrity of the temperature rea ding will be questionable (“ERR” annunciator on). See “Temperature

measurement s ,” page 3-25, for details.

NOTE For RS-232 operation (and in some cases, GPIB operation), *OPC

or *OPC? should be used with :ROUT :MULT :CLOS if the <clist> is large. Details on *OPC and *OPC? are provided in Section 12.

b. ROUTe:MULTiple:OPEN <clist>

With this command, you can open one or more switching module channels. When you send this command to open the channels specified in the <clist>, only those listed channels will open. Channels not specified are not affected.

NOTE For RS-232 operation (and in some cases, GPIB operation), *OPC

or *OPC? should be used with :ROUT:MULT:OPEN if the <clist> is large. Details on *OPC and *OPC? are provided in Section 12.

c. ROUTe:OPEN:ALL

This command functions the same as the front panel OPEN key (ALL menu option). It simply opens all channels (including non-measurement channels) in the mainframe.

d. ROUTe:MULTiple:CLOSe?

This query command returns a <clist> of all closed channels, including non-measurement channels and paired channels for 4-wire functions.

e. ROUTe:MULTiple:CLOSe:STATe? <clist>

This query returns a “0” (open) or “1” (closed) for every channel specified in the <clist>. It is valid for both measurement and non-measurement channels.

For example, assume channel 125 is closed, and you use this command to query channels 101, 104, and 125 (<clist> = (@101, 104, 125)). The response message returns “0, 0, 1” to indicate that channels 101 and 104 are open, and channel 125 is closed.

2-20 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Remote programming example (multiple channel operation)

The following example assumes a Model 7700 installed in slot 1. This command sequence connects channel 101 to channel 111 (through channel 123). Note that these two closed channels will be internally isolated from the DMM since the backplane isolation channels (124 and 125) will be open.

ROUT:OPEN:ALL ' Open all channels. ROUT:MULT:CLOS (@101,111,123) ' Close channels 101, 111 and 123.

When finished with multiple channel operation it is a good, safe practice to open all channels (

ROUT:OPEN:ALL).

Multiple channel operation anomalies

• Anomaly #1 — When you use multiple channel operation to open the system

channel, the channel will open but the system channel number will still be displayed on the Model 2750. For details, see “Anomaly #1 example — wrong

channel displayed.”

• Anomaly #2 — For a 4-wire function, you can use multiple channel operation to

open the paired channel. If you then use system channel operation to again select the already closed system channel, it will not re-close the paired channel. For details, see “Anomaly #2 example — opening the paired channel.”

NOTE The following anomaly examples assume a Model 7700 installed in slot 1.

Anomaly #1 example — wrong c hannel display ed

The following example closes channel 102 and connects it to the DMM Input. However, the Model 2750 will not display the measurement channel that is closed. It will display channel 101 instead of channel 102.

1. Use the ALL option for the OPEN key to open all channels in the mainframe.

Remote programming:

2. Press the  key to close (and display) channel 101. This closes channel 101 (which is the system channel) and channel 125 to connect it to the DMM Input (Figure 2-1).

Remote programming:

3. Use the MULTI option for the CLOSE key to close channel 102. The system channel is not affected. Channels 101, 102, and 125 are now closed.

Remote programming:

4. Use the MULTI option for the OPEN key, open channel 101. Even though channel 101 is still being displayed on the Model 2750, it is channel 102 that is actually connected to the DMM Input (channels 102 and 125 closed).

Remote programming:

ROUT:OPEN:ALL

ROUT:CLOS (@101)

ROUT:MULT:CLOS (@102)

ROUT:MULT:OPEN (@101)

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-21

To correctly display the channel that is closed (channel 102) repeat step 1 above to open all channels, and then use the  key or the

ROUT:CLOS (@102) command to close (and dis-

play) channel 102. This closes channel 102 (which is the system channel) and channel 125 to connect it to the DMM Input.

Anomaly #2 example — opening the paired c hannel

Assume 4-wire connections to a 1kΩ resistor using channels 1 and 11 of the Model 7700 switching module. Also assume the Ω4 function is selected. The following procedure dem- onstrates how careless multiple channel operation can cause an overflow reading even though everything else from the front panel “looks right.”

1. Use the ALL option for the OPEN key (OPEN: ALL) to open all channels in the mainframe.

Remote programming:

2. Press the  key to close (and display) channel 101. The following channels close (see Figure 2-2):

• Channel 101 (system channel).

• Channel 125 (connects channel 101 to DMM Input).

• Channel 111 (paired channel for 4-wire measurements).

• Channel 124 (connects channel 111 to DMM Sense).

• Channel 123 (isolates channel 101 from channel 111).

The Model 2750 will display the 1kΩ reading for system channel 101.

Remote programming:

3. Using the MULTI option for the OPEN key, open channel 111. This opens the connection to DMM Sense and causes an OVRFLW reading. Keep in mind that channel 101 is still closed and displayed as the system channel. Remote programming:

4. In an attempt to clear the overflow reading problem, use the SINGLE option of the CLOSE key to again close channel 101. You might think that this will again close channel 111 to reconnect it to DMM Sense. However, that is not the case. Since channel 101 is still the system channel, selecting it again in this manner is a “no action.” Channel 111 does not close. Remote programming:

ROUT:OPEN:ALL

ROUT:CLOS (@101)

ROUT:MULT:OPEN (@111)

ROUT:CLOS (@101)

A simple way to resolve the above problem is to repeat step 1 to open all channels, and then repeat step 2 to close channel 101. All the listed channels in step 2 will close to make the 4-wire connection to the 1kΩ resistor.

2-22 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Ch 1

Ch 10

Ch 11

Ch 20

Ch 23

(Closed)

Ch 24

Ch 25

Multiplexer A

(1x10)

Multiplexer B

(1x10)

For the dual multiplexer configuration, Ch 23 must be closed, and Ch 24 must remain open.

Channels

2–9

Channels

12–19

Sense

Input

To Model 2750 DMM

Dual independent multiplexers

Using multiple channel operation, an y multi ple xer switching module can be configured as two independent multiplexers. For example, the Model 7700 is normally used as a single 1 × 20 multiplexer, but it can also be configured as two 1 × 10 multiplexers.

NOTE Thermocouple temperature measurements using the internal or external refer-

ence junction cannot be performed when using multiple channel operation to connect an input channel to the DMM. The simulated reference junction will instead be used resulting in invalid readings (“ERR” annunciator turns on). See

“Temperature measurements,” page 3-25, for details.

A multiplexer switching module is configured as two multiplexers by using multiple channel operation to close the 2-pole/4-pole relay. The Model 7700 is configured as two independent multiplexers by closing channel 23. As shown in Figure 2-8, the closed position of channel 23 isolates Multiplexer A (channels 1 through 10) from Multiplexer B (channels 11 through 20).

For the dual multiplexer configuration, only Multiplexer A channels can be internally connected to the DMM of the Model 2750. For the Model 7700, closing channel 25 allows channels 1 through 10 to be measured by the DMM.

When using the dual multiplexer configuration, the sense backplane isolation relay must be kept open to isolate Multiplexer B channels from the sense terminals of the DMM. For the Model 7700, channel 24 must be kept open (Figure 2-8).

Figure 2-8

Dual multiplexer configuration (Model 7700)

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-23

Dual multiplexer application

This application demonstrates how to use the Model 7700 as a dual multiplexer to bias and measure 10 DUT. An e xternal source powers the DUT, while the DMM of the Model 2750 measures the output of the DUT. To prev ent overloading of the external source, each DUT is powered (and measured) separately.

Figure 2-9 shows the connections for this application. The external source is connected to

the Sense terminals of the switching module, and DUT is connected to channels 1 through

10. Channels 11 through 20 are used to connect external power to each DUT. For this application, the 2-pole/4-pole relay and backplane isolation relays of the switch-

ing module are to be controlled as follows:

• Closing channel 23 isolates the input measurement channels (1 through 10) from the external source channels (11 through 20). It also connects the DUT to the external source. This channel must remain closed while testing DUT.

• Opening channel 24 isolates the external source from the backplane of the Model

2750. This channel must remain open while testing DUT.

• Closing channel 25 connects an input channel (1 through 10) to the DMM.

In Figure 2-9, channels 1 and 11 are closed to test DUT 1. A more detailed view of the test for DUT 1 is shown in Figure 2-10. The test for the other DUTs is similar except that different source and measure channels are closed. Closed channels for each DUT test are listed as follows:

Tested

device Closed channels

DUT 1 1, 11, 23 and 25 DUT 6 6, 16, 23 and 25 DUT 2 2, 12, 23 and 25 DUT 7 7, 17, 23 and 25 DUT 3 3, 13, 23 and 25 DUT 8 8, 18, 23 and 25 DUT 4 4, 14, 23 and 25 DUT 9 9, 19, 23 and 25 DUT 5 5, 15, 23 and 25 DUT 10 10, 20, 23 and 25

NOTE Do not use this application to measure the temperature of th e DUT using a

thermocouple with the INTernal or EXTernal reference junction selected. The SIMulated reference junction will instead be used resulting in invalid readings. The “ERR” annunciator will turn on to indicate that the integrity of the temperature reading is questionable.

Tested device Closed channels

2-24 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Ch 1

DUT

H1 LO

Ch 2

DUT

Ch 10

DUT

Ch 11

H1 LO

Ch 12

Ch 20

Ch 23

(Closed)

Ch 25

Ch 24

External

Source

Model 7700 Switching Module

Model 2750

DMM

Sense

Input

Sense

Figure 2-9

Dual multiplexer application connections

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-25

Test procedure:

NOTES The following test procedure assumes a Model 7700 switching module installed

in slot 1 of the mainframe. The procedure assumes that the instrument is operating in the continuous mea-

surement (triggering) mode (see “Defaults and user setups,” page 1-19). Do not use the following procedure to perform thermocouple temperature

measurements with the INTernal or EXTernal reference junction selected. The SIMulated reference junction will instead be used resulting in invalid readings. The “ERR” annunciator will turn on to indicate that the integrity of the temperature reading is questionable.

1. Open all channels. For most switching modules, channels remain closed after the Model 2750 is turned off. Therefore, it is good, safe practice to open all channels at the start and end of the test.

Front panel operation: Press OPEN > Display ALL > Press OPEN Remote programming:

ROUT:OPEN:ALL

2. Close channels 23 and 25.

Front panel operation: Press CLOSE > Select MULTI > Key in 123 >

Press ENTER Press CLOSE > Select MULTI > Key in 125 >

Press ENTER

Remote programming:

ROUT:MULT:CLOS (@123,125)

3. Close channels 1 and 11 to connect DUT #1 to the DMM and bias supply.

Front panel operation: Press CLOSE > Select MULTI > Key in 101 >

Press ENTER Press CLOSE > Select MULTI > Key in 111 >

Press ENTER

Remote programming:

ROUT:MULT:CLOS (@101,111)

4. Measure DUT #1.

Front panel operation: Take reading from display Remote programming:

DATA?

5. Open channels 1 and 11.

Front panel operation: Press OPEN > Select MULTI > Key in 101 >

Press ENTER Press OPEN > Select MULTI > Key in 111 >

Press ENTER

Remote programming:

ROUT:MULT:OPEN (@101,111)

6. Modify steps 3, 4, and 5 to test DUT #2. That is, close channels 2 and 12, measure DUT #2, and then open channels 2 and 12.

2-26 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

DMM

Model 7700 Switching Module

Model 2750

Slot 1

Equivalent Circuit

DUT

Ch 23

(Closed)

DMM

Mutliple channel operation: Open all channels Close channel 123 Close channel 125 Close channel 101 Close channel 111

DUT

External

Source

External

Source

Input

Ch 25

Ch 1

Sense

Ch 24

Ch 11

Sense

7. Test the remaining eight DUT in a similar manner. That is, close the appropriate channels for the DUT, make the measurement, and then open the channels.

8. After the last DUT is tested, repeat step 1 to open all channels.

Figure 2-10

Testing DUT 1

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-27

Identifying installed modules and viewing closed channels

On power-up, the model numbers of installed switching modules are displayed briefly. While in the normal display state, red slot indicators on the right side of the display indicate which slots have a switching module or pseudocard installed.

NOTE If a Model 7700, 7701, 7702, 7703, 7705, 7708, or 7709 switching module is

NOTE If a Model 7706 or 7707 is removed while power is on, error +523 (“Card har d-

ware error”) will occur, and the module will be removed from the system.

NOTE In general, it is not recommended to install or remove switching modules with

the power on.

CARD menu

The CARD menu identifies the switching modules installed in the mainframe, and is used for the following operations:

• Configure digital inputs and outputs, and analog outputs for switching modules that have one or more of those capabilities (i.e., Models 7706 and 7707).

• View the analog input channels that are presently closed. Also, read digital input and output ports, and analog output values for switching modules that have one or more of those capabilities.

Menu navigation keys — Once in the menu structure, the manual range keys ( and the cursor keys ( and ) are used to display menu items and options, and set parameter values. With the desired item, option or setting displayed, press the ENTER key to select it. You can cancel a pending selection (and exit the menu structure) by pressing the EXIT key.

Press the SHIFT key and then the CARD key to display the CARD menu. The Card menu tree is shown in Figure 2-11. The items and options of the menu are explained as follows:

NOTE Identifying installed modules — If you simply want to identify installed modules

or pseudocards, select CONFIG or VIEW and use the slot. While in the menu structure, the slot indicator for the selected slot will be on. The other indicators will be off. When finished, press EXIT.

Δ or ∇ key to check each

Δ and ∇)

2-28 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

CARD: CONFIG — This menu item is used to configure switching modules. The channels of the Model 7700 switching module and other similar type modules do not need to be configured.

SLOTX: 77xx — Use to configure the switching module in Slot X (where X = 1, 2, 3, 4, or 5). If configuration is not necessary, the instrument will exit from the menu when ENTER is pressed.

NOTE For switching modules that require configuration, refer to the packing list that

was shipped with each module.

CARD: VIEW — This menu item is used to view all analog input channels that are presently closed. These include both measurement and non-measurement channels.

The channels are built into a string that scrolls the display . Four dots identify the end of the string. Model 7700 example (Slot 1) — Assume the Ω4 function is selected and system channel 101 is closed. The following string will scroll across the display:

101, 111, 123, 124, 125 . . . .

Channels 101 and 111 are the paired channels for the 4-wire measurement. Channel 123 is the 4-pole relay setting, and channels 124 and 125 connect input and sense to the DMM of the Model 2750 (Figure 2-2).

NOTE Some switching modules have analog outputs, digital inputs, and/or digital out-

puts. The values for these channels are also displayed fr om the VIEW menu item. For details on a pa rticular switching module, refer to the packing list that was shipped with each module.

SLOTX: 77xx — Use to scroll the closed channels and channel settings (if applicable) for the switching module in Slot X (where X = 1, 2, 3, 4, or 5).

Scrolling speed — The scrolling speed of the channel string is adjustable, or can be

paused. The 

key slows do wn scrolling speed and the  key speeds it up. The ENTER

key pauses scrolling. Press ENTER a second time to resume scrolling.

Exiting VIEW —

key will also exit VIEW, but it will also perform the operation associated with the key. For example, pressing Ω2 will exit VIEW, and select the Ω2 function.

To exit from VIEW, press the EXIT key. Pressing an instrument setting

NOTE When a command is received while the display is scrolling, the instrument exits

from the CARD menu and the command is executed.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-29

SHIFT

CARD

CONFIG

VIEW

Scrolls

Channels

SLOT1: 77XX SLOT5: 77XX

77XX = Model number of installed switching module.

SLOT1: 77XX

SLOT5: 77XX

Scrolls

Channels

Figure 2-11

CARD menu tree

Switching module queries (remote oper ation)

For remote operation there are commands to identify installed switching modules and channels that are closed. There are also commands to acquire general information about the installed modules.

*OPT?

For remote operation, the *OPT? command can be used to determine which switching modules (or pseudocards) are installed in the Model 2750. For example, assume a Model 7700 is installed in slot 1, a Model 7706 is installed in slot 2 and the other slots are empty. After sending *OPT? and addressing the Model 2750 to talk, the following response message will be sent to the computer:

7700, 7706, NONE, NONE, NONE

2-30 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

ROUT e:CLOSe? ROUT e:MULTiple:CLOSe? ROUT e:MULTiple:CLOSe:ST A Te? <clist>

These query commands are used to determine closed switching module channels. ROUT:CLOS? is used to return a list of closed measurement channels including the paired

channel for 4-wire measurements. It will not return non-measurement channels. For details, see Table 2-1 and related reference information.

ROUT:MULT:CLOS? is used to return all closed channels (measurement and non-measurement). For details, see Table 2-2 and related reference information.

ROUT:MULT:CLOS:STAT? is used to return the state (open or closed) of each specified channel. A “0” is returned for an open channel, and a “1” is returned for a closed channel. For details, see Table 2-2 and related reference information.

SYST em:C ARD commands

There is a series of SYSTem:CARD commands that can be used to acquire the following information about a switching module installed in the Model 2750:

• Return the serial number and firmware revision.

• Determine the maximum allowable voltage.

• Determine if the module supports multiplexer or isolated channels.

• Determine if the module has built-in temperature sensors for internal cold junction, thermocouple temperature measurements.

• Determine which channels are used for volts/2-wire measurements and which are used for amps.

• Determine which channels are used for analog or digital output.

• Determine the totalizer channel (Model 7706 only).

The SYSTem:CARD commands are covered in Table 15-7.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-31

Relay closur e count

The Model 2750 keeps an internal count of the number of times each module relay has been closed. The total number of relay closures are stored in EEPROM on the card. This count will help you determine if and when any relays require replacement (see module contact life specifications).

Relay closures are counted only when a relay cycles from open to closed state. If you send multiple close commands to the same channel without sending an open command, only the first closure will be counted.

Relay closure count can only be read via remote operation. The commands are summarized in Table 2-3. Details follow the table.

Table 2-3

Relay closure count commands

Commands Description Default

ROUTe:CLOSe:COUNt? <clist> Query close count for specified

channels.

ROUTe:CLOSe:COUNt:INT erv al < NRf> Set count update interval in minutes

(10 to 1440).

ROUTe:CLOSe:CO UNt :INTerval? Query relay count update interval.

Note

Channel list parameter:

<clist> = (@SCH)

where: S = Mainframe slot number (1, 2, 3, 4 or 5)

CH = Switching module channel number (must be 2 digits)

Examples: (@101) = Slot 1, Channel 1

(@101, 203) = Slot 1, Channel 1 and Slot 2, Channel 3 (@101:110) = Slot 1, Channels 1 through 10

Note: Relay count interval set to 15 minutes at the factory. SYSTem:PREset and *RST have no effect on the

set interval.

NOTE The r elay closur e count can be r eset to zer o. For details, see Model 2750 Service

Manual, “Plug-in module relay closure count.”

2-32 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Reading relay closur e count

To determine the closure count of specific channels, send this query via remote:

ROUTe:CLOSe:COUNt? <clist>

Here, <clist> is the summary of channels. For example, to determine the closure count of channels 1 and 4 of a module in slot 1, the following query would be sent:

ROUT:CLOS:COUN? (@101,104)

The following query would determine the closure count of slot 1 module channels 1 through 10:

ROUT:CLOS:COUN? (@101:110)

Setting count update interval

Relay closure counts are updated in temporary RAM every time a channel is closed regardless of how it was closed: by an SCPI command, front panel control, or during a scan. These counts are permanently written to the EEPROM on the card only at a user-set time interval (which is initially set to 15 minutes at the factory), or whenever the counts are queried. Valid intervals (set in integer number of minutes) are between 10 and 1440 minutes (24 hrs).

The lower the interval, the less chance there is of losing relay counts due to power failures. However, writing to the EEPROM more often may reduce scanning throughput. The higher the interval, the less scanning throughput is reduced, but more relay counts may be lost in the event of a power failure.

NOTE If the Model 2750 is turned off before the updated count is written to EEPROM,

the relay counts will be lost. It is good practice to add the ROUT :CLOS:COUN? <clist> command at the end of a program to manually update the count.

To set the count update interval, send this command:

ROUTe:CLOSe:COUNt:INTerval <NRf>

where; <NRf> = 10 to 1440 (minutes) For example, to set the interval to 30 minutes, send this command:

ROUT:CLOS:COUN:INT 30

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-33

Model 7700 switching module

NOTE Connection and wiring procedur es for the Model 7700 are to be performed by

qualified service personnel. This information is provided in Appendix B (Model 7700 Connection Guide).

Switching module capabilities

Channels 1 through 20 — The Model 7700 can multiplex one of 20 2-pole signals, or one of 10 4-pole signals into the input of the Model 2750.

Channels 21 and 22 — The Model 7700 can multiplex one of two 2-pole current signals into the input of the Model 2750.

CAUTION T o prevent damage to the Model 7700 switching module, do not exceed

these maximum signal levels: Channels 1-20: 300VDC or RMS, 1A switched, 60W, 125VA

Channels 21, 22: 60VDC or 30V RMS, 3A switched, 60W, 125VA

NOTE System channel operation – Of the 22 measur ement channels, only one channel

(or channel pair) can be closed at the same time. When you close a channel (or channel pair), all other measurement channels will open. The user has no control of channels 23, 24, and 25. The open/close state of these channels are determined by the selected function.

The Model 7700 has six temperature transducers to monitor the cold junction temperature at the screw terminals. For temperature measurements, this internal reference junction allows thermocouples to be connected directly to the screw terminals of the module.

When the Model 2750 is on the DCV, ACV, Ω2, CONT, Ω4, FREQ, PERIOD, or TEMP function, channels 1 through 20 are available. When on a current function (DCI or ACI), channels 21 and 22 are the only available channels.

The Model 7700 can accommodate 4-wire measurements by using channel pairs. Primary channels 1 through 10 become paired to channels 11 through 20. For example, with the Ω4 function selected, channel 1 becomes paired to channel 11. For example, when you close channel 1, channel 11 will also close.

The 2-wire functions include DCV, ACV, DCI, ACI, Ω2, CONT, FREQ, PERIOD, and TEMP (thermocouple and thermistor). The 4-wire functions/operations include Ω4, TEMP (4-wire RTD), RATIO, and CH AVG (ratio and channel average are covered in Section 5).

With a 4-wire function/operation selected, channels are paired as follows:

• CH1 and CH11 • CH6 and CH16

2-34 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

• CH2 and CH12 • CH7 and CH17

• CH3 and CH13 • CH8 and CH18

• CH4 and CH14 • CH9 and CH19

• CH5 and CH15 • CH10 and CH20

Schematic diagram

The simplified schematic diagram of the Model 7700 is shown in Figure 2-12. Channels 1 through 20 are used for all measurements except amps. Channels 21 and 22 are used for amps only.

There are two backplane relays (channels 24 and 25) to connect the input channel(s) to the backplane of the Model 2750. With a 2-wire function (except amps) selected, channel 25 will close, and with a 4-wire function selected, both channels 24 and 25 will close.

There is a 2-pole/4-pole relay (channel 23) between channels 1-10 and channels 11-20. When a 2-wire function (i.e., DCV) is selected, channel 23 opens (2-pole position) to allow any of the 20 channels to be connected to the input backplane.

When a 4-wire function is selected, channel 23 closes (4-pole position) to isolate channels 1 through 10 from channels 11 through 20. With a system channel (1 through 10) closed, its paired channel (11 through 20) will also close to connect the sense channel to the sense backplane.

For the two current channels (21 and 22), signal HI and LO are routed directly to the backplane when the channel is closed.

As shown in Figure 2-12, there are also screw terminals labeled “Input,” “Sense,” and “Amps.” The Input and Sense terminals are connected to the inputs of channels 24 and 25 (isolation relays). If channels 1 through 20 are not intended to be connected to the internal DMM, channels 24 and 25 can be controlled independently using multiple channel operation. The Amps terminals are connected directly to the DMM.

Notes:

Cold Junction Ref x3

Channel 1

Channel 10

(Channels 2–9)

Channel 11

Channel 20

(Channels 12–19)

Channel 21

Channel 22

AMPS

Sense

Input

Channel 23

2-Pole (Open)

4-Pole (Closed)

(See Note)

To Model 2750 Backplane

Channel 25

(See Note)

Backplane

Isolation

Channel 24

(See Note) Backplane

Isolation

Channels 23 and 25 in this schematic refer to the designations used for control and are not actual available measurement channels.

AMPS

Sense

Input

Cold Junction Ref x3

If the module is not to be internally connected to the DMM, channels 24 and 25 can be opened using multiple channel operation.

Model 2750 Multimeter/Switch System User’s Manual Close/Open Switching Module Channels 2-35

Figure 2-12

Model 7700 simplified schematic

2-36 Close/Open Switching Module Channels Model 2750 Multimeter/Switch System User’s Manual

Basic DMM Operation

• DMM measurement capabilities — Summarizes the measurement capabilities of

the Model 2750 and covers maximum signal levels for switching modules.

• High energy circuit safety precautions — Provides safety information when per-

forming measurements in high energy circuits.

• Performance considerations — Covers some considerations that affect overall

performance including warm-up, autozero, and line synchronization.

• Channel list parameter (<clist>) — Summarizes the use of the <clist> parameter

which is used throughout this manual to configure scan channels.

• Voltage measurements (DCV and ACV) — Provides detailed information for

making basic DC and AC voltage measurements.

• Current measurements (DCI and ACI) — Provides detailed information for

making basic DC and AC current measurements.

• Resistance measurements — Provides detailed information for making resistance

measurements. Also covered are offset compensated ohms (OCOMP) and dry circuit ohms (DR Y CKT ).

• T emperature measurements — Provides detailed information for making thermo-

couple, thermistor, and 4-wire RTD temperature measurements.

• Frequency and period measurements — Provides detailed information for mak-

ing frequency and period measurements.

• Continuity testing — Explains how to use the CONT feature to test continuity.

• Remote programming for basic measurements — Covers the commands used to

perform basic measurements. Includes some simple programming examples.

• Measurement queries — Summarizes commands typically used to trigger and/or

return measured readings.

3-2 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual

DMM measurement capabilities

The DMM of the Model 2750 can make the following measurements: DCV — DC voltage measurements from 0.1µV to 1000V. ACV — AC voltage measurements from 0.1µV to 750V. DCI — DC current measurements from 10nA to 3A. ACI — AC current measurements from 1µA to 3A.

Ω2 — 2-wire resistance measurements from 10µΩ to 120MΩ. Ω4 — 4-wire resistance measurements from 1µΩ to 120MΩ.

FREQ — Frequency measurements from 3Hz to 500kHz. PERIOD — Period measurements from 333ms to 2µs. TEMP — Temperature measurements from -200°C to 1820°C. CONT — Continuity testing using the 1kΩ ran ge.

CAUTION When using a switching module, do not exceed the maximum signal

levels of the module. To prevent damage to the Model 7700 switching module, do not exceed these maximum signal levels:

Channels 1-20: 300VDC or RMS, 1A switched, 60W, 125VA Channels 21, 22: 60VDC or 30V RMS, 3A switched, 60W, 125VA

For the other switching modules, the maximum signal levels are included with their specifications.

NOTE This section shows DUT connections to the front panel inputs of the Model 2750

and to the Model 7700 switching module. Details on Model 7700 connections are provided in Appendix B.

Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-3

High energy cir cuit safety precautions

To optimize safety when measuring voltage in high energy distribution circuits, read and use the directions in the following warning.

WARNING Dangerous arcs of an explosive nature in a high energy circuit can

cause severe personal injury or death. If the multimeter is connected to a high energy circuit when set to a current range or low resistance range the circuit is virtually shorted. Dangerous arcing can result even when the multimeter is set to a voltage range if the minimum voltage spacing is reduced in the external connections.

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, the Model 2750 is Installation Category I and signal lines must not be directly connected to AC mains.

When making measurements in high energy circuits, use test leads that meet the following requirements:

• Test leads should be fully insulated.

• Only use test leads that can be connected to the circuit (e.g., alligator clips, spade lugs, etc.) for hands-off measurements.

• Do not use test leads that decrease voltage spacing. These diminish arc protection and create a hazardous condition.

Use the following sequence when testing power circuits:

1. De-energize the circuit using the regular installed connect-disconnect device, for example, by removing the device's power cord or by turning off the power switch.

2. Attach the test leads to the circuit under test. Use appropriate safety rated test leads for this application. If over 42V, use double insulated test leads or add an additional insulation barrier for the operator.

3. Set the multimeter to the proper function and range.

4. Energize the circuit using the installed connect-disconnect device and make measurements without disconnecting the multimeter.

5. De-energize the circuit using the installed connect-disconnect device.

6. Disconnect the test leads from the circuit under test.

WARNING For the front panel inputs, the maximum common-mode voltage (volt-

age between INPUT LO and the chassis ground) is 500V peak. For a switching module, the maximum common mode voltage is 300V. Exceeding these values may cause a breakdown in insulation, creating a shock hazard.

3-4 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual

P erformance considerations

Warm-up

After the Model 2750 is turned on, it must be allowed to warm up for at least two hours to allow the internal temperature to stabilize. If the instrument has been exposed to extreme temperatures, allow extra warm-up time.

Autozero

To help maintain stability and accuracy over time and changes in temperature, the Model 2750 periodically measures internal voltages corresponding to offsets (zero) and amplifier gains. For thermocouple temperature measurements using the internal reference junction (i.e., Model 7700 switching module installed), the internal temperature is also measured. These measurements are used in the algorithm to calculate the reading of the input signal. This process is known as autozeroing.

When autozero is disabled, the offset, gain, and internal temperature measurements are not performed. This increases the measurement speed. However, the zero, gain, and temperature reference points will eventually drift resulting in inaccurate readings of the input signal. It is recommended that autozero only be disabled for short periods of time.

When autozero is enabled after being off for a long period of time, the internal reference points will not be updated immediately. This will initially result in inaccurate measurements, especially if the ambient temperature has changed by several degrees.

NOTE To force a rapid update of the internal reference points, set the integration rate

to 0.01 PLC, and then back to the desired rate (i.e., 1.0 PLC). The NPLC commands to set the integration rate are covered in Section 4.

Remote programming can be used to enable or disable autozero (Table 3-1). Autozero cannot be disabled from the front panel; however, it can be enabled by restoring factory default conditions.

Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-5

1 PLC

A/D

Conversion

A/D

Conversion

Trigger

# 1

Trigger

# 2

Reading

Done

Reading

Done

LSYNC (line cycle sync hronization)

Synchronizing A/D conversions with the frequency of the power line increases common mode and normal mode noise rejection. When line cycle synchronization is enabled, the measurement is initiated at the first positive-going zero crossing of the power line cycle after the trigger.

Figure 3-1 shows the measurement process that consists of two A/D conversions. If the

trigger occurs during the positive cycle of the po wer line (Trigger #1), the A/D conversion starts with the positive-going zero crossing of the power line cycle. If the next trigger (Trigger #2) occurs during the negative cycle, then the measurement process also starts with the positive-going zero crossing.

Figure 3-1

Line cycle synchronization

Perform the following steps to enable or disable line cycle synchronization:

1. Press SHIFT and then LSYNC to display the present state of line synchronization (OFF or ON).

2. Use the up or down key to display “LINESYNC ON” or “LINESYNC OFF.”

3. Press ENTER. The instrument returns to the normal display state.

NOTE Line synchronization is not available for the AC functions (ACV, ACI, FREQ, or

PERIOD), and for integration rates <1 PLC, regardless of the LSYNC setting.

3-6 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual

Remote programming — autozer o and LSYNC

Autozero and LSYNC commands

The commands to control display resolution (digits) are listed in Table 3-1.

Table 3-1

Autozero and LS YNC commands

Commands Description Default

Autozero command

SYSTem:AZERo:STATe Enable or disable autozero; = ON or

Line synchronization command

SYSTem:LSYNc[:STATe] Enable or disable LSYNC; = ON or

*After enabling autozero, you can update the internal reference points immediately by setting the integration

rate to 0.01 PLC and then back to the desired setting (see NPLC commands in Section 4).

OFF

Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-7

Channel list parameter (<clist>)

Channels of one or more switching modules installed in the Model 2750 can be scanned. Each scan channel can have its own unique setup. For example, a channel could be set to measure DCV on the 10V range, while another channel can be set to measure ACV on the 1V range.

From the front panel, scan channels are configured from the scan configuration menu as explained in Section 7. For remote programming, the <clist> parameter is used to configure scan channels.

Channel list parameter: <clist> = (@SCH) where: S = Mainframe slot number (1, 2, 3, 4 or 5)

CH = Switching module channel number (must be 2 digits)

Examples: (@101) = Slot 1, Channel 1

(@101, 203) = Slot 1, Channel 1 and Slot 2, Channel 3 (@101:110) = Slot 1, Channels 1 through 10

Throughout this manual, you will encounter commands that can use the <clist> parameter. The <clist> simply indicates that the associated command can be used to configure a scan channel. For example:

SENSe:FUNCtion ‘VOLTage:AC’ ' Select ACV function. SENSe:FUNCtion ‘VOLTage:AC’, (@101) ' Configure scan channel 101 for ACV.

While in the normal measurement display state, the first command simply selects the ACV function. The second command configures channel 101 to measure ACV when it is scanned.

See Section 7 for detailed information on scanning.

3-8 Basic DMM Operation Model 2750 Multimeter/Switch System User’s Manual

V oltage measur ements (DCV and ACV)

The Model 2750 can make DCV measurements from 0.1µV to 1000V and ACV measurements from 0.1µV to 750V RMS, 1000V peak.

DCV input resistance: 100 V and 1000V ranges: 10MΩ

100mV, 1V, and 10V ranges: >10GΩ || <400pF or 10MΩ

ACV input impedance: 1MΩ || <100pF

DCV input divider

Normally, the input resistance for the 100mVDC, 1VDC, and 10VDC ranges is >10GΩ, while the input resistance of the 100VDC and 1000VDC ranges is 10MΩ. However, the input resistance for the three lower DCV ranges can also be set to 10MΩ by enabling the input divider.

With the input resistance lowered, a more stable 0V reading is achieved with an open input. Also, some external devices (such as a high voltage probe) must be terminated to a 10MΩ load.

The input divider cannot be enabled from the front panel. For remote programming, the following command controls the input divider:

VOLT:IDIVider ' Enable (ON) or disable (OFF) the DCV input divider.

Connections

WARNING Even though the Model 2750 can measure up to 1000V peak, the maxi-

NOTE When using the front panel inputs, the INPUTS switch must be in the “F” (out)

mum input to a switching module is less. Exceeding the voltage rating of a switching module may cause damage and create a safety hazard.

position. For switching modules, it must be in the “R” (in) position.

Model 2750 Multimeter/Switch System User’s Manual Basic DMM Operation 3-9

Input Impedance = 1MΩ || <100pF Caution: Maximum Input = 750V RMS, 1000V peak, 8 x 10 VHz

Input Resistance =10MΩ on 1000V and 100V ranges;

>10GΩ on 10V, 1V, and 100mV ranges.

Caution: Maximum Input = 1000V peak A. DCV Connections

B. ACV Connections

DC Voltage

Source

AC Voltage

Source

Model 2750 Front Panel

3A, 250V

500V

PEAK

FRONT/REAR

INPUT

SENSE

Ω 4 WIRE

INPUT

350V

PEAK

1000V PEAK

CAT I

AMPS

500V

PEAK

FRONT/REAR

INPUT

SENSE

Ω 4 WIRE

INPUT

350V

PEAK

1000V PEAK

CAT I

Front panel input

When using the front panel input terminals, connect the test leads to the INPUT HI and LO terminals as shown in Figure 3-2.

Figure 3-2

DCV and ACV connections using front panel inputs

Keithley 2750 User guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Safety Precautions

Table of Contents

1 Getting Started

2 Closing and Opening Switching Module Channels

3 Basic DMM Operation

4 Range, Digits, Rate, Bandwidth, and Filter

5 Relative, Math, Ratio, ChannelAver age, and dB

6Buffer

7 Scanning

8 T riggering

9 Limits and Digital I/O

10 Remote Operations

11 Status Structure

12 Common Commands 13 SCPI Signal Oriented Measurement Commands

14 FORMat and Miscellaneous SYST em Commands

15 SCPI Reference Tables

B Model 7700 Connection Guide

E Measurement Considerations

F T emper ature Equations

G IEEE-488 Bus Overvie w

Getting Started

General information

Contact information

Safety symbols and terms

Inspection

Options and accessories

Plug-in switching modules

Connector and adapter kits for switching modules

Cables and adapters (GPIB and trigger link)

Rack mount kit

Model 2750 features

Plug-in switching modules

Pseudocards

Identifying installed switching modules

Fr ont and rear panel familiarization

Front panel summar y

Rear panel summary

Rack mounting

Power-up

Line power connection

Line frequenc y

Setting line voltage and replacing fuse

Po wer -up sequence

Keyclick

Remote programming

Display

Status and error messages

Display commands

Programming e xample

Defaults and user setups

Saving and restoring setups

Saving a user setup

Saving a pow er -on setup

Restoring a setup

Programming e xample

Remote progr amming information

Quick start ex ercises

Close/open operation

Simple scanning

Close/open ov erview

Switching module installation and connections

Module installation

Connections

Pseudocards

Channel assignments

System channel oper ation

2-wire functions

4-wire functions (paired channels)

Controlling the system channel

CLOSE key (SINGLE menu option)

OPEN key (ALL menu option)

Non-amp and non-measure switching modules

Non-amps switching modules

Non-measure switching modules

Multiple channel oper ation

Controlling multiple channels