Keithley Instruments 2700 Service

Model 2700 Multimeter/
Data Acquisition System

Service Manual

Contains Servicing Information

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a
period of 1 year from date of shipment.

Keithley Instruments, Inc. warrants the following items for 90 days from the date of shipment: probes, cables,
rechargeable batteries, diskettes, and documentation.

During the warranty period, we will, at our option, either repair or replace any product that proves to be defec­tive.

To exercise this warranty, write or call your local Keithley representative, or contact Keithley headquarters in
Cleveland, Ohio. You will be given prompt assistance and return instructions. Send the product, transportation
prepaid, to the indicated service facility. Repairs will be made and the product returned, transportation prepaid.
Repaired or replaced products are warranted for the balance of the original warranty period, or at least 90 days.

LIMITATION OF WARRANTY

This warranty does not apply to defects resulting from product modification without Keithley’s express written
consent, or misuse of any product or part. This warranty also does not apply to fuses, software, non-recharge­able batteries, damage from battery leakage, or problems arising from normal wear or failure to follow instruc­tions.

THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUD­ING ANY IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE.
THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES.

NEITHER KEITHLEY INSTRUMENTS, INC. NOR ANY OF ITS EMPLOYEES SHALL BE LIABLE FOR
ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF
THE USE OF ITS INSTRUMENTS AND SOFTWARE EVEN IF KEITHLEY INSTRUMENTS, INC., HAS
BEEN ADVISED IN ADVANCE OF THE POSSIBILITY OF SUCH DAMAGES. SUCH EXCLUDED DAM­AGES SHALL INCLUDE, BUT ARE NOT LIMITED TO: COSTS OF REMOVAL AND INSTALLATION,
LOSSES SUSTAINED AS THE RESULT OF INJURY TO ANY PERSON, OR DAMAGE TO PROPERTY.

Keithley Instruments, Inc.

BELGIUM: Keithley Instruments B.V.
CHINA: Keithley Instruments China
FRANCE: Keithley Instruments Sarl
GERMANY: Keithley Instruments GmbH
GREAT BRITAIN: Keithley Instruments Ltd
INDIA: Keithley Instruments GmbH
ITALY: Keithley Instruments s.r.l.
NETHERLANDS: Keithley Instruments B.V.
SWITZERLAND: Keithley Instruments SA
TAIWAN: Keithley Instruments Taiwan

• 28775 Aurora Road • Cleveland, OH 44139 • 440-248-0400 • Fax: [phone] • http://www.keithley.com

Bergensesteenweg 709 • B-1600 Sint-Pieters-Leeuw • 02/363 00 40 • Fax: [phone]

Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-62022886 • Fax: [phone]
B.P. 60 • 3, allée des Garays • 91122 Palaiseau Cédex • 01 64 53 20 20 • Fax: [phone]
Landsberger Strasse 65 • D-82110 Germering • 089/84 93 07-40 • Fax: [phone]
The Minster • 58 Portman Road • Reading, Berkshire RG30 1EA • 0118-9 57 56 66 • Fax: [phone]
Flat 2B, WILOCRISSA • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
Viale S. Gimignano, 38 • 20146 Milano • 02/48 30 30 08 • Fax: [phone]
Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
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1 Fl. 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3572-9077• Fax: [phone]

10/99

Model 2700 Multimeter/Data Aquisition System

Service Manual

©1999, Keithley Instruments, Inc.

All rights reserved.

Cleveland, Ohio, U.S.A.

Second Printing, February 2000

Document Number: 2700-902-01 Rev. B

Manual Print History

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

Revision A (Document Number 2700-902-01)...........................................................November 1999

Revision B (Document Number 2700-902-01) ............................................................. February 2000

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

Safety Precautions

The following safety precautions should be observed before using this product and any associated in­strumentation. Although some instruments and accessories would normally be used with 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 the operating information carefully
before using the product.

The types of product users are:

Responsible body

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

Operators

and proper use of the instrument. They must be protected from electric shock and contact with hazardous
live circuits.

Maintenance personnel

setting the line voltage or replacing consumable materials. Maintenance procedures are described in the
manual. The procedures explicitly state if the operator may perform them. Otherwise, they should be
performed only by service personnel.

Service personnel

ucts. Only properly trained service personnel may perform installation and service procedures.

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.

practice is to expect that hazardous voltage is present in any unknown circuit before measuring.

Users of this product must be protected from electric shock at all times. The responsible body must en­sure that users are prevented access and/or insulated from every connection point. In some cases, con­nections must be exposed to potential human contact. Product users in these circumstances must be
trained to protect themselves from the risk of electric shock. If the circuit is capable of operating at or
above 1000 volts,

As described in the International Electrotechnical Commission (IEC) Standard IEC 664, digital multi­meter measuring circuits (e.g., Keithley Models 175A, 199, 2000, 2001, 2002, and 2010) are Installation
Category II. All other instruments’ signal terminals are Installation Category I and must not be connect­ed to mains.

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

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

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.

is the individual or group responsible for the use and maintenance of equipment, for

use the product for its intended function. They must be trained in electrical safety procedures

are trained to work on live circuits, and perform safe installations and repairs of prod-

no conductive part of the circuit may be exposed.

perform routine procedures on the product to keep it operating, for example,

A good safety

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

The instrument and accessories must be used in accordance with its specifications and operating instructions
or the safety of the equipment may be impaired.

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

When fuses are used in a product, replace with same type and rating for continued protection against fire hazard.

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

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

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

!

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

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

The

WARNING

read the associated information very carefully before performing the indicated procedure.

heading in a manual explains dangers that might result in personal injury or death. Always

The

CAUTION

invalidate the warranty.

Instrumentation and accessories shall not be connected to humans.

Before performing any maintenance, disconnect the line cord and all test cables.

To maintain protection from electric shock and fire, replacement components in mains circuits, including the
power transformer, test leads, and input jacks, must be purchased from Keithley Instruments. Standard fuses,
with applicable national safety approvals, may be used if the rating and type are the same. Other components
that are not safety related may be purchased from other suppliers as long as they are equivalent to the original
component. (Note that selected parts should be purchased only through Keithley Instruments to maintain ac­curacy and functionality of the product.) If you are unsure about the applicability of a replacement component,
call a Keithley Instruments office for information.

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

heading in a manual explains hazards that could damage the instrument. Such damage may

Rev. 10/99

Table of Contents

1 Performance Verification

Introduction ................................................................................ 1-2

Verification test requirements ..................................................... 1-3

Environmental conditions ................................................... 1-3

Warm-up period .................................................................. 1-3

Line power .......................................................................... 1-3

Recommended test equipment ................................................... 1-4

Verification limits ....................................................................... 1-5

Example reading limit calculation ...................................... 1-5

Calculating resistance reading limits .................................. 1-5

Restoring factory defaults .......................................................... 1-5

Performing the verification test procedures ............................... 1-6

Verification test summary ................................................... 1-6

Test considerations .............................................................. 1-7

Model 2700 verification ............................................................. 1-8

Verifying DC voltage .......................................................... 1-8

Verifying AC voltage ........................................................... 1-9

Verifying DC current ......................................................... 1-11

Verifying AC current ......................................................... 1-12

Verifying resistance ........................................................... 1-13

Verifying temperature ....................................................... 1-15

Verifying frequency .......................................................... 1-17

Model 7700 verification ........................................................... 1-18

Verifying DC voltage ........................................................ 1-18

Verifying AC voltage ......................................................... 1-20

Verifying DC current ......................................................... 1-22

Verifying AC current ......................................................... 1-24

Verifying resistance ........................................................... 1-25

Verifying temperature ....................................................... 1-27

Verifying frequency .......................................................... 1-30

Verifying ratio and average ............................................... 1-30

2 Calibration

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

Environmental conditions ........................................................... 2-2

Warm-up period ................................................................... 2-2

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

Calibration considerations .......................................................... 2-3

Calibration code .......................................................................... 2-4

Front panel calibration code ................................................ 2-4

Remote calibration code ...................................................... 2-4

Comprehensive calibration ......................................................... 2-5

Calibration cycle .................................................................. 2-5

Recommended equipment ................................................... 2-5

Aborting calibration ............................................................ 2-6

Front panel calibration ........................................................ 2-6

Remote calibration ............................................................ 2-13

Manufacturing calibration ........................................................ 2-18

Recommended test equipment .......................................... 2-18

Extender board preparation ............................................... 2-19

Unlocking manufacturing calibration ................................ 2-19

Measuring function generator signal amplitude ................ 2-19

Front panel manufacturing calibration .............................. 2-20

Remote manufacturing calibration .................................... 2-21

Model 7700 calibration ............................................................. 2-22

Recommended test equipment .......................................... 2-22

Extender board connections .............................................. 2-22

Model 7700 calibration ..................................................... 2-22

3 Routine Maintenance

Introduction ................................................................................ 3-2

Setting the line voltage and replacing the line fuse .................... 3-2

Replacing the front terminal AMPS fuse .................................... 3-4

Replacing plug-in module amps fuses ........................................ 3-5

Replacing Model 7700 amps fuses ...................................... 3-5

Replacing Model 7702 amps fuses ...................................... 3-6

Replacing non-volatile RAM battery ......................................... 3-8

4 Troubleshooting

Introduction ................................................................................ 4-2

Repair considerations ................................................................. 4-2

Power-on self-test ....................................................................... 4-2

Front panel tests ......................................................................... 4-3

KEY test .............................................................................. 4-3

DISP test ............................................................................. 4-3

Principles of operation ............................................................... 4-4

Power supply ....................................................................... 4-4

Display board ...................................................................... 4-6

Digital circuitry ................................................................... 4-7

Analog circuitry .................................................................. 4-8

Troubleshooting ....................................................................... 4-11

Display board checks ........................................................ 4-11

Power supply checks ......................................................... 4-11

Digital circuitry checks ..................................................... 4-12

Analog signal switching states .......................................... 4-13

No comm link error .................................................................. 4-18

5 Disassembly

Introduction ................................................................................ 5-2

Handling and cleaning ............................................................... 5-2

Handling PC boards ............................................................ 5-2

Solder repairs ...................................................................... 5-2

Static sensitive devices ........................................................ 5-3

Assembly drawings .................................................................... 5-3

Disassembly procedures ............................................................. 5-4

Case cover removal ............................................................. 5-4

Motherboard removal .......................................................... 5-4

Card cage removal .............................................................. 5-5

Front panel disassembly ...................................................... 5-6

Removing power components ............................................. 5-6

Instrument reassembly ............................................................... 5-7

Input terminal wire connections .......................................... 5-7

Power module wire connections ......................................... 5-7

6 Replaceable Parts

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

Parts lists .................................................................................... 6-2

Ordering information ................................................................. 6-2

Factory service ........................................................................... 6-2

Component layouts .................................................................... 6-2

A Specifications

Accuracy calculations .............................................................. A-12

Calculating DC characteristics accuracy .......................... A-12

Calculating AC characteristics accuracy .......................... A-12

Calculating dBm characteristics accuracy ........................ A-13

Calculating dB characteristics accuracy ........................... A-13

Additional derating factors ............................................... A-14

Optimizing measurement accuracy ......................................... A-14

DC voltage, DC current, and resistance: .......................... A-14

AC voltage and AC current: ............................................. A-14

Temperature: ..................................................................... A-14

Optimizing measurement speed .............................................. A-15

DC voltage, DC current, and resistance: .......................... A-15

AC voltage and AC current: ............................................. A-15

Temperature: ..................................................................... A-15

B Calibration Reference

Introduction ............................................................................... B-2

Command summary ................................................................... B-2

Miscellaneous calibration commands ........................................ B-4

:CODE ................................................................................ B-4

:COUNt? ............................................................................. B-4

:INIT ................................................................................... B-5

:LOCK ................................................................................ B-5

:LOCK? .............................................................................. B-6

:SAVE ................................................................................. B-6

:DATE ................................................................................. B-7

:NDUE ................................................................................ B-7

DC calibration commands ......................................................... B-8

:STEP1 ............................................................................... B-8

:STEP2 ............................................................................... B-9

:STEP3 ............................................................................... B-9

:STEP4 ............................................................................... B-9

:STEP5 ............................................................................. B-10

:STEP6 ............................................................................. B-10

:STEP7 ............................................................................. B-10

:STEP8 ............................................................................. B-11

:STEP9 ............................................................................. B-11

:STEP10 ........................................................................... B-11

:STEP11 ........................................................................... B-12

:STEP12 ........................................................................... B-12

AC calibration commands ....................................................... B-13

:AC:STEP<n> .................................................................. B-14

Manufacturing calibration commands ..................................... B-15

:AC:STEP<14|15> ........................................................... B-15

:DC:STEP0 ...................................................................... B-15

Model 7700 calibration commands ......................................... B-16

:CODE .............................................................................. B-17

:COUNt? .......................................................................... B-17

:DATE? ............................................................................. B-18

:INIT ................................................................................ B-18

:LOCK .............................................................................. B-19

:LOCK? ............................................................................ B-19

:RCOunt ........................................................................... B-19

:SAVE .............................................................................. B-20

:STEP0 ............................................................................. B-20

Remote error reporting ............................................................ B-21

Error summary ................................................................. B-21

Error queue ....................................................................... B-23

Status byte EAV (Error Available) bit .............................. B-23

Generating an SRQ on error ............................................ B-23

Detecting calibration step completion ..................................... B-23

Using the *OPC? query ................................................... B-23

Using the *OPC command ............................................... B-24

Generating an SRQ on calibration complete ................... B-24

C Calibration Program

Introduction ............................................................................... C-2

Computer hardware requirements ............................................. C-2

Software requirements .............................................................. C-2

Calibration equipment ............................................................... C-2

General program instructions .................................................... C-3

List of Illustrations

1 Performance Verification

Figure 1-1 Connections for Model 2700 DC volts verification ................1-8

Figure 1-2 Connections for Model 2700 AC volts verification .................1-9

Figure 1-3 Connections for Model 2700 DC current verification ...........1-11

Figure 1-4 Connections for Model 2700 AC current verification ...........1-12

Figure 1-5 Connections for Model 2700 resistance

verification (100Ω to 10MΩ ranges) ...............................1-13

Figure 1-6 Connections for Model 2700 resistance

verification (100MΩ range) .............................................1-14

Figure 1-7 Connections for Model 2700 frequency verification .............1-17

Figure 1-8 Connections for Model 7700 DC volts verification ..............1-18

Figure 1-9 Connections for Model 7700 AC volts verification ...............1-20

Figure 1-10 Connections for Model 7700 DC current verification ...........1-22

Figure 1-11 Connections for Model 7700 AC current verification ...........1-24

Figure 1-12 Connections for Model 7700 resistance

verification (100Ω to 10MΩ ranges) ...............................1-25

Figure 1-13 Connections for Model 7700 resistance

verification (100MΩ range) .............................................1-26

Figure 1-14 Connections for Model 7700 thermocouple

temperature verification ...................................................1-28

Figure 1-15 Connections for Model 7700 frequency verification .............1-30

Figure 1-16 Connections for Model 7700 ratio and

average verification ..........................................................1-31

2 Calibration

Figure 2-1 Low-thermal short connections ...............................................2-7

Figure 2-2 Connections for DC volts and ohms calibration .....................2-8

Figure 2-3 Connections for DC and AC amps calibration ......................2-10

Figure 2-4 Connections for AC volts calibration ....................................2-11

Figure 2-5 Function generator connections for

manufacturing calibration ................................................2-20

3 Routine Maintenance

Figure 3-1 Power module ..........................................................................3-3

Figure 3-2 Front terminal AMPS fuse ......................................................3-4

Figure 3-3 Model 7700 amps fuses ...........................................................3-5

Figure 3-4 Model 7702 amps fuses ...........................................................3-7

4 Troubleshooting

Figure 4-1 Power supply block diagram ................................................... 4-4

Figure 4-2 Digital circuitry block diagram ............................................... 4-6

Figure 4-3 Analog circuitry block diagram .............................................. 4-9

C Calibration Program

Figure C-1 Model 2700 calibration program ........................................... C-3

List of Tables

1 Performance Verification

Table 1-1 Recommended verification equipment ....................................1-4

Table 1-2 DCV reading limits .................................................................1-9

Table 1-3 ACV reading limits ...............................................................1-10

Table 1-4 DCI limits ..............................................................................1-11

Table 1-5 ACI limits ..............................................................................1-12

Table 1-6 Limits for resistance verification ...........................................1-14

Table 1-7 Thermocouple temperature verification reading limits .........1-16

Table 1-8 Four-wire RTD temperature verification reading limits ........1-17

Table 1-9 Plug-in module DCV reading limits .....................................1-19

Table 1-10 Plug-in module ACV reading limits ......................................1-21

Table 1-11 Plug-in module DCI limits ....................................................1-23

Table 1-12 Plug-in module ACI limits ....................................................1-24

Table 1-13 Limits for plug-in module resistance verification .................1-27

Table 1-14 Model 7700 thermocouple temperature verification

Table 1-15 Plug-in module four-wire RTD temperature

2 Calibration

Table 2-1 Recommended equipment for comprehensive calibration ......2-5

Table 2-2 Comprehensive calibration procedures ...................................2-7

Table 2-3 DC volts calibration summary .................................................2-9

Table 2-4 Ohms calibration summary .....................................................2-9

Table 2-5 DC current calibration summary ...........................................2-10

Table 2-6 AC voltage calibration summary ...........................................2-11

Table 2-7 AC current calibration summary ...........................................2-12

Table 2-8 DC voltage calibration programming steps ...........................2-15

Table 2-9 Resistance calibration programming steps ............................2-15

Table 2-10 DC current calibration programming steps ...........................2-16

Table 2-11 AC voltage calibration programming steps ...........................2-17

Table 2-12 AC current calibration programming steps ...........................2-17

Table 2-13 Recommended equipment for manufacturing calibration .....2-18

Table 2-14 Recommended equipment for Model 7700 calibration .........2-22

reading limits ...................................................................1-28

verification reading limits ................................................1-29

3 Routine Maintenance

Table 3-1 Power line fuse ........................................................................3-3

4 Troubleshooting

Table 4-1 Power supply components ...................................................... 4-5

Table 4-2 Display board checks ............................................................ 4-11

Table 4-3 Power supply checks ............................................................. 4-11

Table 4-4 Digital circuitry checks .........................................................4-12

Table 4-5 DCV signal switching ...........................................................4-13

Table 4-6 ACV and FREQ signal switching .........................................4-13

Table 4-7
Table 4-8
Table 4-9

Table 4-10 DCA signal switching ...........................................................4-15

Table 4-11 ACA signal switching ...........................................................4-15

Table 4-12 DCV signal multiplexing and gain .......................................4-16

Table 4-13 ACV and ACA signal multiplexing and gain ........................4-16

Table 4-14 DCA signal multiplexing and gain .......................................4-16

Table 4-15
Table 4-16

Table 4-17 Switching device locations ...................................................4-17

Ω

2 signal switching .............................................................. 4-14

Ω

4 signal switching .............................................................. 4-14

Ω2/Ω

4 reference switching ................................................... 4-14

Ω

2 signal multiplexing and gain ........................................... 4-17

Ω

4 signal multiplexing and gain ........................................... 4-17

5 Disassembly

Table 5-1 Input terminal wire colors ....................................................... 5-7

Table 5-2 Power module wire colors ......................................................5-7

6 Replaceable Parts

Table 6-1 Model 2700 motherboard parts list .........................................6-3

Table 6-2 Model 2700 display board parts list ........................................ 6-8

Table 6-3 Model 2700 connector board parts list ...................................6-9

Table 6-4 Model 2700 miscellaneous parts list ..................................... 6-10

Table 6-5 Model 7700 parts list ............................................................6-11

Table 6-6 Model 7702 parts list ............................................................6-12

Table 6-7 Model 7703 parts list ............................................................6-13

Table 6-8 Model 7705 parts list ............................................................6-14

B Calibration Reference

Table B-1 Remote calibration command summary ................................ B-2

Table B-2 DC calibration commands ..................................................... B-8

Table B-3 AC calibration commands .................................................... B-13

Table B-4 Model 7700 calibration commands ...................................... B-16

Table B-5 Calibration error summary ................................................... B-21

1

Performance Verification

1-2 Performance Verification

Introduction

Use the procedures in this section to verify that Model 2700 Multimeter/Data Acquisition
System accuracy is within the limits stated in the instrument’s one-year accuracy specifications.
You can perform these verification procedures:

• When you first receive the instrument to make sure that it was not damaged during ship­ment, and that the unit meets factory specifications.

• If the instrument’s accuracy is questionable.

• Following calibration.

WARNING

NOTE

There are three general verification procedures in this section:

•

Model 2700 verification

Model 2700 using the front panel terminals.

Model 7700 verification

•
made through the Model 7700 20-Channel Multiplexer. Note that the same general pro­cedures can be used to verify measurement accuracy of other Model 2700 plug-in mod­ules that have similar functions. For specific information about the individual modules,
refer to the appropriate appendices in the Model 2700 User’s Manual.

The information in this section is intended only for qualified service per­sonnel. Do not attempt these procedures unless you are qualified to do so.

If the instrument is still under warranty and its performance is outside specified lim­its, contact your Keithley representative or the factory to determine the correct
course of action. If the unit is not under warranty, and it fails to meet specified limits,
refer to the calibration procedures in Section 2.

: Covers procedures to verify measurement accuracy of the

: Discusses procedures to verify accuracy of measurement

Verification test requirements

Be sure that you perform the verification tests:

• Under the proper environmental conditions.

• After the specified warm-up period.

• Using the correct line voltage.

• Using the proper calibration equipment.

• Using the specified reading limits.

Environmental conditions

Conduct your performance verification procedures in a test environment that has:

• An ambient temperature of 18° to 28°C (65° to 82°F).

• A relative humidity of less than 80% unless otherwise noted.

Warm-up period

Allow the Model 2700 to warm up for at least two hours before conducting the verification

procedures.

Performance Verification 1-3

If the instrument has been subjected to temperature extremes (those outside the ranges stated
above), allow additional time for the instrument’s internal temperature to stabilize. Typically,
allow one extra hour to stabilize a unit that is 10°C (18°F) outside the specified temperature
range.

Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.

Line power

The Model 2700 requires a line voltage of 100V/120V/220V/240V, ±10% and a line
frequency of 45Hz to 66Hz. Note that the line frequency is automatically sensed at power-up,
but the line voltage must be manually set to either 100V/120V or 220V/240V as described in
Section 3.

1-4 Performance Verification

Recommended test equipment

Table 1-1 summarizes recommended verification equipment. You can use alternate

equipment as long as that equipment has specifications at least as good as those listed in

Table 1-1. Keep in mind, however, that calibrator uncertainty will add to the uncertainty of each

measurement.

Table 1-1

Recommended verification equipment

Fluke 5700A Calibrator:

AC voltage

DC voltage

100mV:±14ppm

1.0V:±7ppm
10V:±5ppm
100V:±7ppm
1000V:±9ppm

Fluke 5725A Amplifier:

AC Voltage, 50kHz: 700V, ±375ppm
DC Current, 3A, ±500ppm
AC Current, 1kHz, 3A, ±457ppm

Keithley 3930A or 3940 Frequency Synthesizer:

1V RMS, 10V RMS, 1kHz, ±5ppm, steady state and burst modulation

General Radio 1433-T Precision Decade Resistance Box:

Ω

to 400Ω, ±0.02%

10

Miscellaneous Equipment:

Double banana plug to double banana plug shielded cables (2)
BNC to double banana plug shielded cable

NOTE: The Fluke 5725A amplifier is necessary only if you wish to verify the 750V AC range at 50kHz and 3A AC and DC current

ranges at 3A. Verification at 220V, 50kHz, and 2.2A on the current ranges using only the 5700A calibrator is adequate for
most applications.

(1kHz, 50kHz) DC current

100mV:±200ppm

1.0V:±82ppm
10V:±82ppm
100V:±90ppm
700V:±85ppm

10mA:±60ppm
100mA:±70ppm
1A:±110ppm

2.2A:±94ppm

AC current
(1kHZ) Resistance

1A:±690ppm

2.2A:±682ppm

100

Ω

1k

Ω

10k

Ω

100k
1M

Ω

10M
100M

:±17ppm

:±12ppm

:±11ppm

Ω

:±13ppm

:±18ppm

Ω

:±37ppm

Ω

:±120ppm

Verification limits

The verification limits stated in this section have been calculated using only the Model 2700
one-year accuracy specifications, and they do not include test equipment uncertainty. If a par­ticular measurement falls slightly outside the allowable range, recalculate new limits based on
both Model 2700 specifications and pertinent calibration equipment specifications.

Example reading limit calculation

The following is an example of how reading limits have been calculated. Assume you are
testing the 10V DC range using a 10V input value. Using the Model 2700 one-year accuracy
specification for 10V DC of ± (30ppm of reading + 5ppm of range), the calculated limits are:

Performance Verification 1-5

Reading limits = 10V ± [(10V

Reading limits = 10V ± (0.0003 + 0.00005)

Reading limits = 10V ± 0.00035V

Reading limits = 9.99965V to 10.00035V

Calculating resistance reading limits

Resistance reading limits must be recalculated based on the actual calibration resistance val­ues supplied by the equipment manufacturer. Calculations are performed in the same manner as
shown in the preceding example, except, of course, that you should use the actual calibration
resistance values instead of the nominal values when performing your calculations.

For example, assume that you are testing the 10k
tion resistance value. Using Model 2700 one-year 10k
ing + 6ppm of range), the calculated reading limits are:

Reading limits = 10.03k

Reading limits = 10.02894k

Ω

± [(10.03kΩ × 100ppm) + (10kΩ × 6ppm)]

Ω

Restoring factory defaults

Before performing the verification procedures, restore the instrument to its factory defaults
as follows:

×

30ppm) + (10V × 5ppm)]

Ω

range using an actual 10.03kΩ calibra-

Ω

to 10.03106k

Ω

range accuracy of ± (100ppm of read-

1. Press

2. Using either range key, select FACT, then restore the factory default conditions by

SHIFT

and then

RESTORE: FACT.

pressing

ENTER

.

SETUP

. The instrument will display the following prompt:

1-6 Performance Verification

Performing the verification test procedures

Verification test summary

Verification tests can be performed either through the Model 2700 front panel terminals or

through plug-in modules. This section contains the following procedures:

•

Model 2700 verification

front panel terminals.

Model 7700 verification

•
available plug-in modules with the same functions as the Model 7700 20-Channel
Multiplexer Card.

Model 2700 tests

Model 2700 verification test procedures include:

• DC volts

• AC volts

• DC current

• AC current

• Resistance

• Temperature

• Frequency

: Use this procedure to test Model 2700 accuracy through the

: Use this procedure to test accuracy through any of the

Model 7700 tests

Model 7700 verification test procedures include:

• DC volts

• AC volts

• DC current

• AC current

• Resistance

• Temperature

• Frequency

• Ratio and average

Test considerations

When performing the verification procedures:

• Be sure to restore factory defaults as outlined above.

• Make sure that the equipment is properly warmed up and connected to the correct input
terminals. Also make sure that the INPUTS switch is in the correct position.

• Do not use autoranging for any verification tests because autorange hysteresis may
cause the Model 2700 to be on an incorrect range. For each test signal, you must manu­ally set the correct range for the Model 2700 using the range keys.

• Make sure the calibrator is in operate before you verify each measurement.

• Always let the source signal settle before taking a reading.

Performance Verification 1-7

WARNING

Observe the following safety precautions when performing these tests:

•

Some of the procedures in this section may expose you to dangerous
voltages. Use standard safety precautions when such dangerous volt­ages are encountered to avoid personal injury or death caused by elec­tric shock.

•

For the front panel terminals only, the maximum common-mode volt­age (voltage between INPUT LO and chassis ground) is 500V peak.
Exceeding this value may cause a breakdown in insulation, creating a
shock hazard.

•

For the plug-in modules, the maximum common-mode voltage (volt­age between any plug-in module terminal and chassis ground) is 300V
DC or 300V RMS. Exceeding this value may cause a breakdown in
insulation, creating a shock hazard.

•

When using the front panel terminals simultaneously with plug-in
modules, all cable insulation voltage ratings must equal or exceed the
maximum voltage applied to either the front panel terminals or the
plug-in module terminals.

1-8 Performance Verification

Model 2700 verification

Perform these tests to verify accuracy using the Model 2700 front panel terminals.

Verifying DC voltage

Check DC voltage accuracy by applying accurate voltages from the DC voltage calibrator to
the Model 2700 INPUT jacks and verifying that the displayed readings fall within specified
limits.

CAUTION

Do not exceed 1000V peak between front terminals INPUT HI and
INPUT LO because instrument damage may occur.

Follow these steps to verify DC voltage accuracy:

1. Connect the Model 2700 HI and LO INPUT jacks to the DC voltage calibrator as
shown in Figure 1-1. Make sure the INPUTS switch is set to the FRONT position.

NOTE

Use shielded, low-thermal connections when testing the 100mV and 1V ranges to
avoid errors caused by noise or thermal effects. Connect the shield to the calibra­tor’s output LO terminal.

Figure 1-1

Connections for Model 2700 DC volts verification

Model 2700

LOCAL

POWER

Integra Series

Model 2700 Multimeter / Data Acquisition System

CONT

LIMITS ON/OFFDELAY

RECALL

STEP SCAN

CH AVG

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

TRIG

EX TRIG

STORE

SAVE SETUP

CONFIG HALT

CLOSE

OPEN

RANGE

RANGE

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

PEAK

LO

500V
PEAK

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Input HI

Output HI

Input
LO

Output
LO

Calibrator (Output DC Voltage)

Note: Use shielded, low-thermal cables

for 100mV and 1V ranges.

2. Select the DC volts function by pressing the

DCV

key, and set the Model 2700 to the

100mV range.

3. Set the calibrator output to 0.00000mV DC, and allow the reading to settle.

4. Enable the Model 2700 REL mode. Leave REL enabled for the remainder of the DC
volts verification tests.

5. Source positive and negative and full-scale voltages for each of the ranges listed in

Table 1-2. For each voltage setting, be sure that the reading is within stated limits.

Table 1-2

DCV reading limits

Range Applied DC voltage* Reading limits (1 year, 18° to 28°C)

100mV
1V
10V
100V
1000V

*Source positive and negative values for each range.

100.0000mV

1.000000V

10.00000V

100.0000V

1000.000V

Verifying AC voltage

Check AC voltage accuracy by applying accurate AC voltages at specific frequencies from
the AC voltage calibrator to the Model 2700 inputs and verifying that the displayed readings
fall within specified ranges.

Performance Verification 1-9

99.9935 to 100.0065mV

0.999963 to 1.000037V

9.99965 to 10.00035V

99.9946 to 100.0054V

999.931 to 1000.069V

CAUTION

Do not exceed 1000V peak between front terminals INPUT HI and
INPUT LO, or 8

Follow these steps to verify AC voltage accuracy:

1. Connect the Model 2700 HI and LO INPUT jacks to the AC voltage calibrator as shown
in Figure 1-2. Be sure the INPUTS switch is in the FRONT position.

Figure 1-2

Connections for Model 2700 AC volts verification

Note: Amplifier required only

for 700V, 50kHz output.

Model 2700

POWER

Integra Series

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

RANGE

RANGE

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

PEAK

LO

500V
PEAK

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Shielded cable

×

107 V•Hz input, because instrument damage may occur.

Amplifier (Connect to calibrator)

Input HI

Output HI

Input
LO

Output
LO

Calibrator (Output AC Voltage)

1-10 Performance Verification

2. Select the AC volts function by pressing the

ACV

key.

3. Set the Model 2700 for the 100mV range; make sure that REL is disabled.

4. Source 1kHz and 50kHz AC voltages for each of the ranges summarized in Table 1-3,
and make sure that the respective Model 2700 readings fall within stated limits.

Table 1-3

ACV reading limits

ACV
range

100mV
1V
10V
100V
750V

* If the 5725A amplifier is not available, change the 700V @ 50kHz step to 220V @ 50kHz. Reading

limits for 220V @ 50kHz = 219.36 to 220.64V.

Applied AC
voltage

100.0000mV

1.000000V

10.00000V

100.0000V

700.000V*

1kHz reading limits
(1 year, 18°C to 28°C)

99.910 to 100.090mV

0.99910 to 1.00090V

9.9910 to 10.0090V

99.910 to 100.090V

699.36 to 700.64V

50kHz reading limits
(1 year, 18°C to 28°C)

99.830 to 100.170mV

0.99830 to 1.00170V

9.98300 to 10.0170V

99.830 to 100.170V

698.79 to 701.21V

Verifying DC current

Check DC current accuracy by applying accurate DC currents from the DC current calibra­tor to the AMPS input of the Model 2700 and verifying that the displayed readings fall within
specified limits.

Follow these steps to verify DC current accuracy:

1. Connect the Model 2700 AMPS and INPUT LO jacks to the calibrator as shown in

Figure 1-3. Be sure the INPUTS switch is in the FRONT position.

Figure 1-3

Connections for Model 2700 DC current verification

Model 2700

POWER

Integra Series

Model 2700 Multimeter / Data Acquisition System

CONT

RECALL

CH AVG

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

FREQ

TEMP

CH-OFF CARD

RELFILTER

LSYNC

RS-232

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

RANGE

RANGE

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

PEAK

LO

500V

PEAK

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Input
LO

Output HI

Amps

Output
LO

Performance Verification 1-11

Calibrator (Output DC Current)

Note: Be sure calibrator is set for

normal current output.

2. Select the DC current measurement function by pressing the

DCI

key.

3. Set the Model 2700 for the 20mA range.

4. Source positive and negative full-scale currents for each of the ranges listed in

Table 1-4, and verify that the readings for each range are within stated limits.

Table 1-4

DCI limits

DCI range Applied DC current* Reading limits (1 year, 18°C to 28°C)

20mA
100mA
1A
3A

20.0000mA

100.0000mA

1.000000A

3.000000A**

* Source positive and negative currents with values shown.

** If the Fluke 5725 amplifier is not available, apply 2.2A from calibrator. Reading limits for 2.2A

input are: 2.197240 to 2.202760A.

19.89960 to 20.01040mA

99.9100 to 100.0900mA

0.999160 to 1.000840A

2.99628 to 3.00372A

1-12 Performance Verification

Verifying AC current

Check AC current accuracy by applying accurate AC voltage current at specific frequencies
from the AC current calibrator to the Model 2700 input, and verifying that the displayed read­ings fall within specified limits. Follow these steps to verify AC current:

1. Connect the Model 2700 AMPS and INPUT LO jacks to the calibrator as shown in

Figure 1-4. Be sure the INPUTS switch is in the FRONT position.

Figure 1-4

Connections for Model 2700 AC current verification

Model 2700

POWER

Integra Series

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

LSYNC

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

RANGE

RANGE

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

PEAK

LO

500V

PEAK

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Output HI

Input

LO

Output
LO

Calibrator (Output AC Current)

Amps

2. Select the AC current function by pressing the ACI key.

3. Set the Model 2700 for the 1A range.

4. Source 1A and 3A, 1kHz full-scale AC currents as summarized in Table 1-5, and verify
that the readings are within stated limits.

Table 1-5

ACI limits

ACV range Applied AC voltage Reading limits @ 1kHz (1 year, 18°C to 28°C)

1A
3A

* If the Fluke 5725A amplifier is not available, apply 2.2A from the calibrator. Reading limits for 2.2A are

2.1949 to 2.2051A.

1.000000A

3.00000A*

0.99860 to 1.00140A

2.9937 to 3.0063A

Verifying resistance

Check resistance by connecting accurate resistance values to the Model 2700 and verifying

that its resistance readings are within the specified limits.

CAUTION Do not apply more than 1000V peak between front terminals INPUT HI

and LO or more than 350V peak between SENSE HI and LO, or instru­ment damage could occur.

Follow these steps to verify resistance accuracy:

1. Using shielded, Teflon-insulated or equivalent cables in a 4-wire configuration, connect
the Model 2700 INPUT and SENSE jacks to the calibrator as shown in Figure 1-5. Be
sure the INPUTS switch is in the FRONT position.

Figure 1-5

Connections for Model 2700 resistance verification (100Ω to 10MΩ ranges)

Performance Verification 1-13

LOCAL

POWER

Sense HI

Sense HI

Resistance Calibrator

Model 2700

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

!

RANGE

RANGE

PEAK

LO

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

LIMITS ON/OFFDELAY

TRIG

EX TRIG

STORE

SAVE SETUP

CONFIG HALT

CLOSE

OPEN

STEP SCAN

Input
HI

1000V
PEAK

500V
PEAK

Input
LO

Output
HI

Output
LO

Sense LO

Sense LO

Note: Use shielded low-thermal cables to

minimize noise. Enable or disable
calibrator external sense as indicated
in procedure.

2. Set the calibrator for 4-wire resistance with external sense on.

3. Select the Model 2700 4-wire resistance function by pressing the Ω4 key, then choose
the SLOW integration rate with the RATE key.

4. Set the Model 2700 for the 100Ω range, and make sure the FILTER is on. Enable
OCOMP (offset-compensated ohms) for 100Ω range verification. (Press SHIFT then
OCOMP.)

5. Recalculate reading limits based on actual calibrator resistance values.

1-14 Performance Verification

6. Source the nominal full-scale resistance values for the 100Ω-10MΩ ranges summarized
in Table 1-6, and verify that the readings are within calculated limits.

7. Connect the Model 2700 INPUT and SENSE jacks to the calibrator as shown in

Figure 1-6.

8. Disable external sense on the calibrator.

9. Set the Model 2700 for the 100MΩ range.

10. Source a nominal 100MΩ resistance value, and verify that the reading is within calcu­lated limits for the 100MΩ range.

Figure 1-6

Connections for Model 2700 resistance verification (100MΩ range)

Model 2700

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

GPIB

EXIT ENTER

ACI

POWER

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

CLOSE

LIMITS ON/OFFDELAY

TRIG

STORE

CONFIG HALT

STEP SCAN

LOCAL

Sense LO

Table 1-6

Limits for resistance verification

Nominal

Ω Range

100Ω∗
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

resistance

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

Integra Series

RANGE

AUTO

RANGE

Sense HI

SENSE

Ω 4 WIRE

HI

350V

!

PEAK

LO

INPUTS

F

R

FRONT/REAR

INPUT

3A 250V

AMPS

Input
HI

1000V
PEAK

500V
PEAK

Input
LO

Output

HI

Output
LO

Calibrator (Output 2-wire Resistance)

Note: Use shielded cables to minimize noise.

Disable calibrator external sense mode.

Nominal reading limits
(1 year, 18°C to 28°C) Recalculated limits**

99.9884 to 100.0116Ω

0.999894 to 1.000106kΩ

9.99894 to 10.00106kΩ

99.9890 to 100.0110kΩ

0.999890 to 1.000110MΩ

9.99590 to 10.00410MΩ

99.7970 to 100.2030MΩ

__________ to __________ Ω
__________ to __________ kΩ
__________ to __________ kΩ
__________ to __________ kΩ
__________ to __________ MΩ
__________ to __________ MΩ
__________ to __________ MΩ

* Enable O COMP (offset-compensated ohms) when testing 100Ω range.

** Calculate limits based on actual calibration resistance values and Model 2700 one-year resistance accuracy specifications. See

Verification limits.

Verifying temperature

Thermocouple, thermistor, and RTD temperature readings are derived from DC volts and
resistance measurements respectively. For that reason, it is not necessary to independently ver­ify the accuracy of temperature measurements. As long as the DC volts and resistance functions
meet or exceed specifications, temperature function accuracy is automatically verified. How­ever, temperature verification procedures are provided below for those who wish to separately
verify temperature accuracy.

Thermocouple temperature

1. Connect the DC voltage calibrator output terminals to the Model 2700 INPUT jacks
using low-thermal shielded connections. (Use 2-wire connections similar to those
shown in Figure 1-1.) Be sure the INPUTS switch is in the FRONT position.

2. Configure the Model 2700 for °C units, type J temperature sensor, and 0°C simulated
reference junction as follows:

a. Press SHIFT then SENSOR, and note the unit displays the temperature units:

UNITS: C. (If necessary, use the cursor and range keys to select °C units.)

b. Press ENTER. The unit displays the sensor type: SENS: TCOUPLE.

c. Make sure that TCOUPLE is displayed, then press ENTER. The unit then displays

the thermocouple type: TYPE: K.

d. Select a type J temperature sensor, then press ENTER. The unit then displays the

reference junction type: JUNC: SIM.

e. Make certain that the simulated reference junction type is selected, then press

ENTER. The unit then displays the current simulated reference junction tempera­ture: SIM: 023.

f. Using the cursor and range keys, set the reference junction temperature to 0°C,

then press ENTER twice to complete the temperature configuration process.

3. Select the temperature function by pressing the TEMP key.

Performance Verification 1-15

1-16 Performance Verification

4. Source each of the voltages summarized in Table 1-7, and verify that the temperature
readings are within limits. Be sure to select the appropriate thermocouple type for each
group of readings. (See step 2 above.)

Table 1-7

Thermocouple temperature verification reading limits

Thermocouple type Applied DC voltage* Reading limits (1 year, 18°C to 28°C)

J

-7.659mV
0mV

42.280mV

K

-5.730mV
0mV

54.138mV

* Voltages shown are based on ITS-90 standard using 0°C reference junction temperature. See text for pro-

cedure to set reference junction temperature.

-190.2 to -189.9°C

-0.2 to +0.2°C

749.8 to 750.2°C

-190.2 to -189.8°C

-0.2 to +0.2°C

1349.8 to 1350.2°C

RTD temperature

1. Connect the precision decade resistance box (listed in Table 1-1) to the Model 2700
INPUT and SENSE jacks using four-wire connections. (See Figure 1-5 for similar con­necting scheme.) Be sure the INPUTS switch is in the FRONT position.

2. Configure the Model 2700 temperature function for ˚C units and RTD temperature sen­sor (α=0.00385) as follows:

a. Press SHIFT then SENSOR, and note the unit displays the temperature units:

UNITS: C.

b. Press ENTER, and note the unit displays the sensor type: SENS: TCOUPLE.

c. Using the cursor and range keys, set the display as follows: SENS: 4W-RTD.

d. Press ENTER, and note the unit displays: TYPE: PT100.

e. Using the cursor and range keys, set the unit for the following display: TYPE:

PT385.

f. Press ENTER to complete the temperature configuration process.

3. Select the temperature function by pressing the TEMP key.

Performance Verification 1-17

4. Set the decade resistance box to each of the values shown in Table 1-8, and verify that
the temperature readings are within the required limits.

Table 1-8

Four-wire RTD temperature verification reading limits

Applied resistance* Reading limits (1 year, 18°C to 28°C)

22.80Ω

100.00Ω

313.59Ω

-190.06 to -189.94°C

-0.06 to +0.06°C

599.94 to 600.06°C

*Based on α = 0.00385. See text.

Verifying frequency

Follow the steps below to verify the Model 2700 frequency function:

1. Connect the function generator to the Model 2700 INPUT jacks. (See Figure 1-7.) Be
sure the INPUTS switch is in the FRONT position.

2. Set the function generator to output a 1kHz, 1V RMS sine wave.

3. Select the Model 2700 frequency function by pressing the FREQ key.

4. Verify that the Model 2700 frequency reading is between 999.9Hz and 1.0001kHz.

Figure 1-7

Connections for Model 2700 frequency verification

BNC-to-Dual

Banana Plug

Adapter

Model 2700

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

INPUTS

F

FRONT/REAR

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

POWER

Model 2700 Multimeter / Data Acquisition System

CONT

RECALL

CH AVG

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

FREQ

TEMP

RANGE

CH-OFF CARD

GPIB

EXIT ENTER

AUTO

RANGE

RS-232

RELFILTER

LSYNC

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

CLOSE

LIMITS ON/OFFDELAY

TRIG

STORE

CONFIG HALT

STEP SCAN

LOCAL

Function Generator

50Ω

Coax

Cable

Function

Output

1-18 Performance Verification

Model 7700 verification

Use these procedures to verify measurement accuracy through the Model 7700 20-Channel

Multiplexer Card.

NOTE Although the following tests are based on the Model 7700 20-Channel Multiplexer,

the same general procedures can be used for other plug-in modules that have similar
capabilities. Refer to the Model 2700 User’s Manual for specific information on ter­minals and connections for other plug-in modules.

Verifying DC voltage

Check DC voltage accuracy by applying accurate voltages from the DC voltage calibrator to
the Model 7700 input terminals and verifying that the displayed readings fall within specified
limits.

CAUTION Do not exceed 300V DC between plug-in module INPUT H and L termi-

nals or between any adjacent channels.

Follow these steps to verify DC voltage accuracy:

1. Connect the Model 7700 CH1 H and L INPUT terminals to the DC voltage calibrator as
shown in Figure 1-8.

NOTE Use shielded, low-thermal connections when testing the 100mV and 1V ranges to

avoid errors caused by noise or thermal effects. Connect the shield to the calibra­tor’s output LO terminal.

Figure 1-8

Connections for Model 7700 DC volts verification

CH1

INPUT SENSE

HLHL

HLHL

HLHL
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

LO

AMPS

HLHL

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10
HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

CH5

CH6

CH4

CH3

CH1 CH2

Model 7700

Output HI

Output
LO

Calibrator (Output DC Voltage)

Note: Use shielded, low-thermal cables

for 100mV and 1V ranges.

Performance Verification 1-19

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the DC volts function by pressing the DCV key, and set the Model 2700 to the
100mV range. Close Channel 1 by pressing the CLOSE key and then keying in 101.

4. Set the calibrator output to 0.00000mV DC, and allow the reading to settle.

5. Enable the Model 2700 REL mode. Leave REL enabled for the remainder of the DC
volts verification tests.

6. Source positive and negative and full-scale voltages for each of the ranges listed in

Table 1-9. For each voltage setting, be sure that the reading is within stated limits.

7. Press the OPEN key to open Channel 1.

Table 1-9

Plug-in module DCV reading limits

Range Applied DC voltage* Reading limits (1 year, 18° to 28°C)

100mV
1V
10V
100V
1000V

*Source positive and negative values for each range.

100.0000mV

1.000000V

10.00000V

100.0000V

300.000V

99.9935 to 100.0065mV

0.999963 to 1.000037V

9.99965 to 10.00035V

99.9946 to 100.0054V

299.976 to 300.024V

1-20 Performance Verification

Verifying AC voltage

Check AC voltage accuracy by applying accurate AC voltages at specific frequencies from
the AC voltage calibrator to the Model 7700 inputs and verifying that the displayed readings
fall within specified ranges.

CAUTION Do not exceed 300V RMS between plug-in module INPUT H and L termi-

nals or between adjacent channels, or 8 × 10
ment damage may occur.

Follow these steps to verify AC voltage accuracy:

1. Connect the Model 7700 CH1 H and L INPUT terminals to the AC voltage calibrator as
shown in Figure 1-9.

Figure 1-9

Connections for Model 7700 AC volts verification

CH1

CH5

CH6

CH4

CH3

CH1 CH2

INPUT SENSE

HLHL

HLHL

HLHL
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

LO

AMPS

HLHL

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Output HI

7

V•Hz input, because instru-

Amplifier (Connect to calibrator)

Model 7700

Shielded

Cable

Output

LO

Calibrator (Output AC Voltage)

Performance Verification 1-21

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the AC volts function by pressing the ACV key. Close Channel 1 by pressing the
CLOSE key and then keying in 101.

4. Set the Model 2700 for the 100mV range; make sure that REL is disabled.

5. Source 1kHz and 50kHz AC voltages for each of the ranges summarized in Table 1-10,
and make sure that the respective Model 2700 readings fall within stated limits.

6. Press the OPEN key to open Channel 1.

Table 1-10

Plug-in module ACV reading limits

ACV
range

100mV
1V
10V
100V
750V

* If the 5725A amplifier is not available, change the 300V @ 50kHz step to 220V @ 50kHz. Read-

ing limits for 220V @ 50kHz = 219.36 to 220.64V.

Applied AC
voltage

100.0000mV

1.000000V

10.00000V

100.0000V

300.000V*

1kHz reading limits
(1 year, 18°C to 28°C)

99.910 to 100.090mV

0.99910 to 1.00090V

9.9910 to 10.0090V

99.910 to 100.090V

299.60 to 300.40V

50kHz reading limits
(1 year, 18°C to 28°C)

99.830 to 100.170mV

0.99830 to 1.00170V

9.98300 to 10.0170V

99.830 to 100.170V

299.27 to 300.73V

1-22 Performance Verification

Verifying DC current

Check DC current accuracy by applying accurate DC currents from the DC current calibra­tor to the input terminals of the Model 7700 and verifying that the displayed readings fall
within specified limits.

Follow these steps to verify DC current accuracy:

1. Connect the Model 7700 CH21 H and L terminals to the calibrator as shown in

Figure 1-10.

Figure 1-10

Connections for Model 7700 DC current verification

INPUT SENSE

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

CH21

HLHL

Model 7700

CH3

CH1 CH2

HLHL

HLHL

LO

AMPS

CH4

CH5
HLHL

HLHLHLHLHLHL

CH6

CH7 CH8 CH9 CH10
HLHLHLHL

HLHLHLHL
CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Output HI

Output

LO

Calibrator (Output DC Current)

Note: Be sure calibrator is set for

normal current output.

Performance Verification 1-23

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the DC current measurement function by pressing the DCI key.

4. Set the Model 2700 for the 20mA range. Close Channel 21 by pressing the CLOSE key,
and keying in 121.

5. Source positive and negative full-scale currents for each of the ranges listed in

Table 1-11, and verify that the readings for each range are within stated limits.

6. Press the OPEN key to open Channel 21.

Table 1-11

Plug-in module DCI limits

DCI range Applied DC current* Reading limits (1 year, 18°C to 28°C)

20mA
100mA
1A
3A

* Source positive and negative currents with values shown.

** If the Fluke 5725 amplifier is not available, apply 2.2A from calibrator. Reading limits for 2.2A

input are: 2.197240 to 2.202760A.

20.0000mA

100.0000mA

1.000000A

3.000000A**

19.89960 to 20.01040mA

99.9100 to 100.0900mA

0.999160 to 1.000840A

2.99628 to 3.00372A

1-24 Performance Verification

Verifying AC current

Check AC current accuracy by applying accurate AC voltage current at specific frequencies
from the AC current calibrator to the Model 7700 input terminals and verifying that the dis­played readings fall within specified limits. Follow these steps to verify AC current:

1. Connect the Model 7700 CH21 H and L terminals to the calibrator as shown in

Figure 1-11.

Figure 1-11

Connections for Model 7700 AC current verification

INPUT SENSE

HLHL

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

CH21

Model 7700

CH1 CH2
HLHL

LO

HLHL

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

CH5

CH6

CH4

CH3

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the AC current function by pressing the ACI key.

4. Set the Model 2700 for the 1A range. Close Channel 21 by pressing the CLOSE key
and keying in 121.

5. Source 1A and 3A, 1kHz full-scale AC currents as summarized in Table 1-12, and ver­ify that the readings are within stated limits.

6. Press the OPEN key to open Channel 21.

Table 1-12

Plug-in module ACI limits

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Calibrator (Output AC Current)

Output

HI

Output

LO

ACV range Applied AC voltage Reading limits @ 1kHz (1 year, 18°C to 28°C)

1A
3A

* If the Fluke 5725A amplifier is not available, apply 2.2A from the calibrator. Reading limits for 2.2A are

2.1949 to 2.2051A.

1.000000A

3.00000A*

0.99860 to 1.00140A

2.9937 to 3.0063A

Verifying resistance

Check resistance by connecting accurate resistance values to the Model 7700 and verifying

that its resistance readings are within the specified limits.

CAUTION Do not apply more than 300V between plug-in module INPUT or SENSE

H and L terminal, or between any adjacent channels, or instrument dam­age could occur.

Follow these steps to verify resistance accuracy:

1. Using shielded Teflon or equivalent cables in a 4-wire configuration, connect the
Model 7700 CH1 H and L INPUT terminals, and CH11 H and L SENSE terminals to
the calibrator as shown in Figure 1-12.

Figure 1-12

Connections for Model 7700 resistance verification (100Ω to 10MΩ ranges)

CH1

Sense HI

Output

HI

INPUT SENSE

HLHL

Model 7700

CH4

CH3

CH1 CH2

HLHL

HLHL

CH5

HLHL

CH6

CH7 CH8 CH9 CH10
HLHLHLHL

INPUT

(V, 2 WIRE)

Performance Verification 1-25

Resistance Calibrator

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

LO

AMPS

CH11

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow

3. Set the calibrator for 4-wire resistance with external sense on.

4. Select the Model 2700 4-wire resistance function by pressing the Ω4 key. Close Chan-

5. Set the Model 2700 for the 100Ω range, and make sure the FILTER is on. Enable

6. Recalculate reading limits based on actual calibrator resistance values.

SENSE

(OHMS, 4 WIRE)

Output

LO

HLHLHLHLHLHL

HLHLHLHL
CH17 CH18 CH19 CH20

Sense LO

Note: Use shielded, low-thermal cables

to minimize noise. Enable or disable
calibrator external sense as indicated
in procedure.

the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

nel 1 by pressing the CLOSE key and keying in 101.

OCOMP (offset-compensated ohms) for the 100Ω range test. (Press SHIFT then
OCOMP.)

1-26 Performance Verification

7. Source the nominal full-scale resistance values for the 100Ω-10MΩ ranges summarized
in Table 1-13, and verify that the readings are within calculated limits.

8. Connect the Model 7700 CH1 and CH11 terminals to the calibrator as shown in

Figure 1-13.

9. Disable external sense on the calibrator.

10. Set the Model 2700 for the 100MΩ range.

11. Source a nominal 100MΩ resistance value, and verify that the reading is within calcu­lated limits for the 100MΩ range.

12. Press the OPEN key to open Channel 1.

Figure 1-13

Connections for Model 7700 resistance verification (100MΩ range)

CH1

Model 7700

INPUT SENSE
HLHL

HLHL
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

HLHL

LO

AMPS

HLHL

CH4

CH3

CH1 CH2

CH11

CH5

CH6

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

HLHLHLHL
CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Calibrator (Output 2-wire Resistance)

Output

HI

Output

LO

Note: Use shielded cables to minimize

noise. Disable calibrator external
sense mode.

Table 1-13

Limits for plug-in module resistance verification

Performance Verification 1-27

Nominal resis-

Ω Range

100Ω∗
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

* Enable OCOMP for 100Ω range.

** Calculate limits based on actual calibration resistance values and Model 2700 one-year resistance accuracy specifications. See

Verification limits.

tance

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

Nominal reading limits
(1 year, 18°C to 28°C) Recalculated limits**

99.9884 to 100.0116Ω

0.999894 to 1.000106kΩ

9.99894 to 10.00106kΩ

99.9890 to 100.0110kΩ

0.999890 to 1.000110MΩ

9.99590 to 10.00410MΩ

99.5770 to 100.4230MΩ

__________ to __________ Ω
__________ to __________ kΩ
__________ to __________ kΩ
__________ to __________ kΩ
__________ to __________ MΩ
__________ to __________ MΩ
__________ to __________ MΩ

Verifying temperature

Thermocouple, thermistor, and RTD temperature readings are derived from DC volts and
resistance measurements respectively. For that reason, it is not necessary to independently ver­ify the accuracy of temperature measurements. As long as the DC volts and resistance functions
meet or exceed specifications, temperature function accuracy is automatically verified. How­ever, temperature verification procedures are provided below for those who wish to separately
verify temperature accuracy.

Thermocouple temperature

1. Connect the DC voltage calibrator output terminals and ice point reference to the
Model 7700 CH1 H and L INPUT terminals using low-thermal shielded connections, as
shown in Figure 1-14.

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the temperature function by pressing the TEMP key. Close Channel 1 by press­ing the CLOSE key and keying in 101.

4. Configure the Model 2700 for °C units, type K temperature sensor, and internal refer­ence junction as follows:

a. Press SHIFT then SENSOR, and note the unit displays the temperature units:

UNITS: C. (If necessary, use the cursor and range keys to select °C units.)

b. Press ENTER. The unit then displays the sensor type: SENS: TCOUPLE.

c. Make sure that TCOUPLE is displayed, then press ENTER. The unit displays the

thermocouple type: TYPE: J.

d. Select a type K temperature sensor, then press ENTER. The unit then displays the

reference junction type: JUNC: SIM.

e. Select INT reference junction, then press ENTER.

1-28 Performance Verification

5. Source each of the voltages summarized in Table 1-14 and verify that the temperature
readings are within limits. Be sure to select the appropriate thermocouple type for each
group of readings. (See step 3 above.) Open Channel 1 after the test is complete.

Table 1-14

Model 7700 thermocouple temperature verification reading limits

Thermocouple type Applied DC voltage* Reading limits (1 year, 18°C to 28°C)

J

-7.659mV
0mV

42.280mV

K

-5.730mV
0mV

54.138mV

*Voltages shown are based on ITS-90 standard.

Figure 1-14

Connections for Model 7700 thermocouple temperature verification

CH1

INPUT SENSE
HLHL

HLHL
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

HLHL

LO

AMPS

HLHL

CH4

CH3

CH1 CH2

Model 7700

CH5

CH6

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

HLHLHLHL
CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Twisted

Thermocouple Wire

Output

HI

Output

-191.0 to -189.0°C

-1.0 to +1.0°C

749.0 to 751.0°C

-191.0 to -189.0°C

-1.0 to +1.0°C

1349.0 to 1351.0°C

Calibrator (Output DC Voltage)

LO

Low Thermal

Copper Connection

Make HI and LO

Connections

in Ice Bath

Ice Bath

Notes: This setup and reading limits table

does not include errors from
ice point, thermocouple wire,
and connections.

HI and LO connections from
the calibrator and Model 7700
must be electrically isolated
from each other.

Performance Verification 1-29

RTD temperature

1. Connect the precision decade resistance box (listed in Table 1-1) to the Model 7700
CH1 and CH11 H and L terminals using four-wire connections. (See Figure 1-12 for
similar connecting scheme.)

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the temperature function by pressing the TEMP key. Close Channel 1 by press­ing the CLOSE key and keying in 101.

4. Configure the Model 2700 temperature function for ˚C units and RTD temperature sen­sor (α=0.00385) as follows:

a. Press SHIFT then SENSOR, and note the unit displays the temperature units:

UNITS: C.

b. Press ENTER, and note the unit displays the sensor type: SENS: TCOUPLE.

c. Using the cursor and range keys, set the display as follows: SENS: 4W-RTD.

d. Press ENTER, and note the unit displays: TYPE: PT100.

e. Using the cursor and range keys, set the unit for the following display: TYPE:

PT385.

f. Press ENTER to complete the temperature configuration process.

5. Set the decade resistance box to each of the values shown in Table 1-15, and verify that
the temperature readings are within the required limits. Open Channel 1when finished.

Table 1-15

Plug-in module four-wire RTD temperature verification reading limits

Applied resistance* Reading limits (1 year, 18°C to 28°C)

22.80Ω

100.00Ω

313.59Ω

*Based on α = 0.00385. See text.

-190.06 to -189.94°C

-0.06 to +0.06°C

599.94 to 600.06°C

1-30 Performance Verification

Verifying frequency

Follow the steps below to verify the Model 2700 frequency function:

1. Connect the function generator to the Model 7700 CH1 H and L INPUT terminals. (See

Figure 1-15.)

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for one hour before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Set the function generator to output a 1kHz, 1V RMS sine wave.

4. Select the Model 2700 frequency function by pressing the FREQ key. Close Channel 1
by pressing the CLOSE key and keying in 101.

5. Verify that the Model 2700 frequency reading is between 0.9999kHz and 1.0001kHz.

Figure 1-15

Connections for Model 7700 frequency verification

CH1

INPUT SENSE

HLHL

HLHL

HLHL
CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

LO

AMPS

HLHL

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10
HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

CH5

CH6

CH4

CH3

CH1 CH2

Model 7700

Verifying ratio and average

Follow the procedure below to verify ratio and average.

CAUTION Exceeding 300V between plug-in module INPUT or SENSE H and L ter-

1. Connect the Model 7700 CH1 and CH11 H and L terminals to the DC calibrator, as
shown in Figure 1-16.

2. Install the Model 7700 in Slot 1 of the Model 2700, then turn on the power, and allow
the unit to warm up for two hours before proceeding. Be sure the front panel INPUTS
switch is set to the REAR position.

3. Select the Model 2700 DCV function and the 1V range. Close Channel 1 by pressing
the CLOSE key and keying in 101.

INPUT

(V, 2 WIRE)

50Ω

Coax Cable

SENSE

(OHMS, 4 WIRE)

Function

Output

minals may cause instrument damage.

Function Generator

4. Select the Model 2700 RATIO function (press SHIFT then RATIO).

5. Set the calibrator output to 1.00000V DC, and allow the reading to settle.

6. Verify that the ratio reading is between 0.9999926 and 1.000074.

7. Press OPEN to open Channel 1.

Figure 1-16

Connections for Model 7700 ratio and average verification

CH1

Model 7700

CH5

CH6

CH4

CH3

CH1 CH2

INPUT SENSE

HLHL

HLHL

HLHL

HLHL

CH7 CH8 CH9 CH10
HLHLHLHL

INPUT

(V, 2 WIRE)

Performance Verification 1-31

DC Voltage Calibrator

Output

HI

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

LO

AMPS

CH11

HLHLHLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

SENSE

(OHMS, 4 WIRE)

Output

LO

Note: Use shielded cables to minimize noise.

1-32 Performance Verification

2

Calibration

2-2 Calibration

Introduction

Use the procedures in this section to calibrate the Model 2700. Calibration procedures

include:

• Comprehensive calibration: Usually the only calibration required in the field.

• Manufacturing calibration: Usually only performed at the factory (unless the unit has
been repaired).

• Model 7700 calibration: Covers calibration procedures specific to Model 7700 cards.

WARNING The information in this section is intended only for qualified service per-

sonnel. Do not attempt these procedures unless you are qualified to do so.

All the procedures require accurate calibration equipment to supply precise DC and AC volt­ages, DC and AC currents, and resistance values. Comprehensive calibration can be performed
any time by an operator either from the front panel, or by using the SCPI commands sent either
over the IEEE-488 bus or the RS-232 port. DC-only and AC-only calibration may be performed
individually, if desired.

Environmental conditions

Conduct the calibration procedures in a location that has:

• An ambient temperature of 18° to 28°C (65° to 82°F)

• A relative humidity of less than 80% unless otherwise noted

Warm-up period

Allow the Model 2700 Multimeter/Data Acquisition system to warm up for at least two
hours before performing calibration.

If the instrument has been subjected to temperature extremes (those outside the ranges stated
above) allow extra time for the instrument’s internal temperature to stabilize. Typically, allow
one extra hour to stabilize a unit that is 10°C (18°F) outside the specified temperature range.

Also, allow the test equipment to warm up for the minimum time specified by the
manufacturer.

Line power

The Model 2700 requires a line voltage of 100V/120V/220V/240V, ±10% and a line fre­quency of 45Hz to 66Hz. Note that the line frequency is automatically sensed at power-up, but
the line voltage must be manually set to either 100V/120V or 220V/240V as described in
Section 3.

Calibration considerations

When performing the calibration procedures:

• Make sure that the equipment is properly warmed up and connected to the appropriate
input jacks. Also make sure that the correct front or rear terminals are selected with the
INPUTS switch.

• Make sure the calibrator is in OPERATE before you complete each calibration step.

• Always let the source signal settle before calibrating each point.

• If an error occurs during calibration, the Model 2700 will generate an appropriate error
message. See Appendix B for more information.

WARNING Observe the following safety precautions when performing these tests:

• Some of the procedures in this section may expose you to dangerous

voltages. Use standard safety precautions when such dangerous
voltages are encountered to avoid personal injury or death caused by
electric shock.

• For the front panel terminals only, the maximum common-mode volt­age (voltage between INPUT LO and chassis ground) is 500V peak.
Exceeding this value may cause a breakdown in insulation, creating a
shock hazard.

Calibration 2-3

• For the plug-in modules, the maximum common-mode voltage (volt­age between any plug-in module terminal and chassis ground) is 300V
DC or 300V RMS. Exceeding this value may cause a breakdown in
insulation, creating a shock hazard.

• When using the front panel terminals simultaneously with plug-in
modules, all cable insulation voltage ratings must equal or exceed the
maximum voltage applied to either the front panel terminals or the
plug-in module terminals.

2-4 Calibration

Calibration code

Before performing comprehensive calibration, you must first unlock calibration by entering

the appropriate calibration code.

Front panel calibration code

For front panel calibration, follow these steps:

1. Access the calibration menu by pressing SHIFT then TEST, then use the up or down
range key to display TEST: CALIB. Press ENTER, and note that the instrument dis­plays the following:

CAL: DATES

2. Use the up or down range key to scroll through the available calibration items until the
unit displays RUN, then press ENTER.

3. The Model 2700 then prompts you to enter a code:

CODE? 000000

(The factory default code is 002700.) Use the left and right arrow keys to move among
the digits; use the up range key to increment numbers, and press the down range key to
specify alphabetic letters. Confirm the code by pressing ENTER.

4. The Model 2700 allows you to define a new calibration code. Use the up and down
range keys to toggle between yes and no. Choose N if you do not want to change the
code. Choose Y if you want to change the code. The unit then prompts you to enter a
new code. Enter the code, and press ENTER.

Remote calibration code

If you are performing calibration over the IEEE-488 bus or the RS-232 port, send this com-

mand to unlock calibration:

:CAL:PROT:CODE '<8-character string>'.

The default code command is:

:CAL:PROT:CODE 'KI002700'.

To change the code via remote, simply send the :CAL:PROT:CODE command twice, first

with the present code, then with the new code.

Comprehensive calibration

The comprehensive calibration procedure calibrates the DCV, DCI, ACV, ACI, and ohms
functions. You can also choose to calibrate only the DCV/DCI and resistance or ACV/ACI
functions.

These procedures are usually the only calibration required in the field. Manufacturing cali­bration is normally done only at the factory, but it should also be done in the field if the unit has
been repaired. See “Manufacturing calibration” at the end of this section for more information.

Calibration cycle

Perform comprehensive calibration at least once a year, or every 90 days to ensure the unit
meets the corresponding specifications.

Recommended equipment

Table 2-1 lists the recommended equipment you need for comprehensive, DC-only, and

AC-only calibration procedures. You can use alternate equipment, such as a DC transfer stan­dard and characterized resistors, as long that equipment has specifications at least as good as
those listed in the table.

Calibration 2-5

Table 2-1

Recommended equipment for comprehensive calibration

Fluke 5700A Calibrator:

AC voltage

DC voltage

10V:±5ppm
100V: ±7ppm

Miscellaneous equipment:

Keithley 8610 low-thermal shorting plug
Double banana plug to double banana plug shielded cable
BNC to double banana plug shielded cable

*1kHz specifications. 10mV and 700V points require 1kHz only. All calibrator specifications are 90-day, 23°C ±5°C specifications

and indicate total absolute uncertainty at specified output.

(1kHz, 50kHz)* DC current

10mV:±710ppm
100mV:±200ppm
1V:±82ppm
10V:±82ppm
100V:±90ppm
700V:±85ppm

10mA:±60ppm
100mA:±70ppm
1A:±110ppm

AC current
(1kHz) Resistance

100mA:±190ppm
1A:±690ppm
2A:±670ppm

1kΩ:±12ppm
10kΩ:±11ppm
100kΩ:±13ppm
1MΩ:±18ppm

2-6 Calibration

Aborting calibration

Front panel calibration

You can abort the front panel calibration process at any time by pressing EXIT. The instru-

ment will then ask you to confirm your decision to abort with the following message:

ABORT CAL?

Press EXIT to abort calibration at this point, or press any other key to return to the calibra-

tion process.

NOTE The Model 2700 will not respond to any remote programming commands while the

ABORT CAL? message is displayed.

Follow the steps in the following paragraphs in the order shown for comprehensive, DC

only, and AC only calibration procedures.

The procedures for front panel calibration include:

• Preparing the Model 2700 for calibration

• Front panel short and open calibration

• DC voltage calibration

• Resistance calibration

• DC current calibration

• AC voltage calibration

• AC current calibration

• Setting calibration dates

Preparing the Model 2700 for calibration

1. Turn on the Model 2700, and allow it to warm up for at least two hours before perform­ing a calibration procedure.

2. Start the calibration process as follows:

a. Access the calibration menu by pressing SHIFT then TEST, then display TEST:

CALIB using the up or down range key. Press ENTER.

b. Use the up or down range key to scroll through the available calibration menu

items until the unit displays RUN, then press ENTER.

c. At the prompt, enter the calibration code. (The default code is 002700.) Use the

left and right arrow keys to move among the digits; use the up range key to incre­ment numbers, and press the down range key to specify alphabetic letters. Confirm
the code by pressing ENTER.

d. Choose N at the prompt to proceed without changing the code, then press ENTER.

3. Choose which of the calibration tests summarized in Table 2-2 you want to run at the

Fi

1

CAL: RUN prompt. Use the up and down range keys to scroll through the options;
select your choice by pressing ENTER.

Table 2-2

Comprehensive calibration procedures

Procedure Menu choice Procedures

Calibration 2-7

Full calibration
DCV, DCI, and ohms
ACV and ACI

gure 2-

Low-thermal short
connections

ALL
DC
AC

All comprehensive calibration steps (DC and AC)
DC voltage, DC current, and resistance calibration
AC voltage and AC current calibration

Front panel short and open calibration

At the Model 2700 prompt for a front panel short, do the following:

1. Connect the Model 8610 low-thermal short to the instrument front panel INPUT and
SENSE terminals as shown in Figure 2-1. Make sure the INPUTS button is not pressed
in so that the front inputs are selected. Wait at least three minutes before proceeding to
allow for thermal equilibrium.

HI

INPUT

HI

1000V

!

!

PEAK

LO

500V

PEAK

R

3A 250V

AMPS

Model 8610

Low-thermal

short

LO

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

OUTPUT

ACV

HOLD

TRIG

CLOSE

RATIO

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

Model 2700

Model 2700 Multimeter / Data Acquisition System

CONT

OCOMP

CH AVG

RECALL

ACI

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

PERIOD SENSOR

FREQ

CH-OFF CARD

RELFILTER

LSYNC

GPIB

EXIT ENTER

Integra Series

TEMP

RS-232

S+

SENSE

Ω 4 WIRE

350V

PEAK

INPUTS

F

RANGE

F
F

AUTO

FRONT/REAR

RANGE

S-

NOTE Be sure to connect the low-thermal short properly to the HI, LO, and SENSE termi-

nals. Keep drafts away from low-thermal connections to avoid thermal drift, which
could affect calibration accuracy.

2-8 Calibration

2. Press ENTER to start short-circuit calibration. While the unit is calibrating, it will
display:

CALIBRATING

3. When the unit is finished with short-circuit calibration, it will display the following
prompt:

OPEN CIRCUIT

4. Remove the calibration short, and press ENTER. During this phase, the
CALIBRATING message will be displayed.

NOTE Be sure to minimize movement near front Input terminals. Excessive movements can

cause capacitive coupling errors, which could affect calibration accuracy.

DC volts calibration

After the front panel short and open procedure, the unit will prompt you for the first DC

voltage: +10V. Do the following:

1. Connect the calibrator to the Model 2700 as shown in Figure 2-2. Wait three minutes to
allow for thermal equilibrium before proceeding.

Figure 2-2

Connections for DC volts and ohms calibration

POWER

Sense HI

Sense HI

DC Voltage and Resistance Calibrator

Model 2700

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

!

RANGE

RANGE

PEAK

LO

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

Input
HI

1000V
PEAK

500V
PEAK

Input
LO

Output
HI

Output
LO

Sense LO

Sense LO

Note: Use shielded low-thermal cables to minimize noise.

Enable or disable calibrator external sense as
indicated in procedure.

NOTE Although 4-wire connections are shown, the sense leads are connected and discon-

nected at various points in this procedure by turning calibrator external sense on or
off as appropriate. If your calibrator does not have provisions for turning external
sense on and off, disconnect the sense leads when external sensing is to be turned off,
and connect the sense leads when external sensing is to be turned on.

2. Set the calibrator to output DC volts, and turn external sense off.

Calibration 2-9

3. Perform the steps listed in Table 2-3 to complete DC volts calibration. For each calibra-
tion step:

• Set the calibrator to the indicated value, and make sure it is in OPERATE.

• Press the ENTER key to calibrate that step.

• Wait until the Model 2700 finishes each step. (The unit will display the
CALIBRATING message while calibrating.)

NOTE If your calibrator cannot output the values recommended in Table 2-3, use the left and

right arrow keys, and the up and down range keys to set the Model 2700 display value
to match the calibrator output voltage.

Table 2-3

DC volts calibration summary

Calibration step Calibrator voltage Allowable range

+10V

-10V
100V

+10.00000V

-10.00000V
+100.0000V

+9V to +11V

-9V to -11V
+90V to +110V

Resistance calibration

Completing the 100V DC calibration step ends the DC voltage calibration procedure. The

Model 2700 will then prompt you to connect 1kΩ. Follow these steps for resistance calibration:

1. Set the calibrator output for resistance, and turn on external sense.

NOTE Use external sense (4-wire Ω) when calibrating all resistance ranges. Be sure that

the calibrator external sense mode is turned on.

2. Perform the calibration steps summarized in Table 2-4. For each step:

• Set the calibrator to the indicated value, and place the unit in operate. (If the cali­brator cannot output the exact resistance value, use the Model 2700 left and right
arrow keys and the range keys to adjust the Model 2700 display to agree with the
actual calibrator resistance.)

• Press the ENTER key to calibrate each point.

• Wait for the Model 2700 to complete each step before continuing.

Table 2-4

Ohms calibration summary

Calibration step Calibrator resistance* Allowable range

1kΩ
10kΩ
100kΩ
1MΩ

*Nominal resistance. Adjust Model 2700 calibration parameter to agree with actual value.

1kΩ
10kΩ
100kΩ
1MΩ

0.9kΩ to 1.1kΩ
9kΩ to 11kΩ
90kΩ to 110kΩ

0.9MΩ to 1.1MΩ

2-10 Calibration

DC current calibration

After the 1MΩ resistance point has been calibrated, the unit will prompt you to apply 10mA.

Follow these steps for DC current calibration:

1. Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as
shown in Figure 2-3.

Figure 2-3

Connections for DC and AC amps calibration

Model 2700

POWER

Integra Series

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

LSYNC

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

RANGE

RANGE

SENSE

Ω 4 WIRE

HI

350V

!

PEAK

LO

INPUTS

F

R

AUTO

FRONT/REAR

DC and AC Current Calibrator

Input

1000V
PEAK

500V

PEAK

LO

Output HI

INPUT

3A 250V

AMPS

Amps

Output
LO

Note: Be sure calibrator is set for

normal current output.

2. Calibrate each current step summarized in Table 2-5. For each step:

• Set the calibrator to the indicated DC current, and make sure the unit is in
OPERATE.

• Make sure the Model 2700 display indicates the correct calibration current.

• Press ENTER to complete each step.

• Allow the Model 2700 to finish each step.

NOTE If you are performing DC-only calibration, proceed to “Setting calibration dates

and saving calibration.”

Table 2-5

DC current calibration summary

Calibration step Calibrator current Allowable range

10mA
100mA
1A

10.00000mA

100.0000mA

1.000000A

9mA to 11mA
90mA to 110mA

0.9A to 1.1A

AC voltage calibration

Follow these steps for AC voltage calibration:

1. Connect the calibrator to the Model 2700 INPUT HI and LO terminals as shown in

Figure 2-4.

Figure 2-4

Connections for AC volts calibration

Calibration 2-11

POWER

Input HI

AC Voltage Calibrator

Model 2700

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

!

RANGE

RANGE

PEAK

LO

INPUTS

F

R

AUTO

FRONT/REAR

3A 250V

AMPS

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

FREQ

TEMP

CH-OFF CARD

RELFILTER

RS-232

LSYNC

GPIB

EXIT ENTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

EX TRIG

SAVE SETUP

OPEN

TRIG

CLOSE

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

LOCAL

1000V
PEAK

500V
PEAK

Output HI

Input
LO

Output
LO

2. Perform the calibration steps summarized in Table 2-6. For each step:

• Set the calibrator to the indicated value, and make sure the calibrator is in
OPERATE.

• Press ENTER to complete each step.

• Wait until the Model 2700 completes each step.

Table 2-6

AC voltage calibration summary

Calibration step Calibrator voltage, frequency

10mV AC at 1kHz
100mV AC at 1kHz
100mV AC at 50kHz
1V AC at 1kHz
1V AC at 50kHz
10V AC at 1kHz
10V AC at 50kHz
100V AC at 1kHz
100V AC at 50kHz
700V AC at 1kHz

10.00000mV, 1kHz

100.0000mV, 1kHz

100.0000mV, 50kHz

1.000000V, 1kHz

1.000000V, 50kHz

10.00000V, 1kHz

10.00000V, 50kHz

100.0000V, 1kHz

100.0000V, 50kHz

700.000V, 1kHz

2-12 Calibration

AC current calibration

After the 700VAC at 1kHz point has been calibrated, the unit will prompt you for 100mA at

1kHz. Follow these steps for AC current calibration:

1. Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as
shown in Figure 2-3.

2. Perform the calibration steps summarized in Table 2-7. For each step:

• Set the calibrator to the indicated current and frequency, and make sure the unit is
in OPERATE.

• Press ENTER to complete each calibration step.

• Allow the unit to complete each step before continuing.

Table 2-7

AC current calibration summary

Calibration step Calibrator current, frequency

100mA at 1kHz
1A at 1kHz
2A at 1kHz

100.0000mA, 1kHz

1.000000A, 1kHz

2.000000A, 1kHz

Setting calibration dates and saving calibration

At the end of the calibration procedure, the instrument will display the CALIBRATION
COMPLETE message. Press ENTER to continue, and the Model 2700 will prompt you to enter
the calibration date and the calibration due date. Set these dates as follows:

1. At the CAL DATE: prompt, use the left and right arrow keys, and the range keys to set
the calibration date, then press ENTER.

2. The unit will then prompt you to enter the next calibration due date with this prompt:
CAL NDUE:. Use the left and right arrow keys, and the range keys to set the calibration
due date, then press ENTER.

3. The unit will prompt you to save new calibration constants with this message: SAVE
CAL? YES. To save the new constants, press ENTER. If you do not want to save the
new constants, press the down range key to toggle to NO, then press ENTER.

NOTE Calibration constants calculated during the present calibration procedure will not

be saved unless you choose the YES option. Previous calibration constants will be
retained if you select NO.

Remote calibration

Follow the steps in this section to perform comprehensive procedures via remote. See

Appendix B for a detailed list and description of remote calibration commands.

When sending calibration commands, be sure that the Model 2700 completes each step
before sending the next command. You can do so either by observing the front panel CALI­BRATING message, or by detecting the completion of each step over the bus. (See “Detecting
calibration step completion” in Appendix B.)

The procedures for calibrating the Model 2700 via remote include:

• Preparing the Model 2700 for calibration

• Front panel short and open calibration

• DC volts calibration

• Resistance calibration

• DC current calibration

• AC volts calibration

• AC current calibration

• Programming calibration dates

• Saving calibration constants

• Locking out calibration

Calibration 2-13

NOTE As with front panel calibration, you can choose to perform comprehensive, DC-only,

or AC-only calibration. Be sure to include a space character between each command
and parameter.

Preparing the Model 2700 for calibration

1. Connect the Model 2700 to the IEEE-488 bus of the computer using a shielded
IEEE-488 cable, such as the Keithley Model 7007, or connect the unit to a computer
through the RS-232 port using a straight-through 9-pin to 9-pin cable (use a 9-25-pin
adapter if necessary).

2. Turn on the Model 2700, and allow it to warm up for at least two hours before perform­ing calibration.

3. Make sure the primary address of the Model 2700 is the same as the address specified
in the program that you will be using to send commands. (Use the GPIB key.)

4. Unlock the calibration function by sending this command:

:CAL:PROT:CODE 'KI002700'

(The above command shows the default code, KI002700. Substitute the correct code if
changed.)

5. Send the following command to initiate calibration:

:CAL:PROT:INIT

2-14 Calibration

Short and open calibration

1. Connect the Model 8610 low-thermal short to the instrument INPUT and SENSE termi­nals as shown in Figure 2-1. Make sure the INPUTS button is not pressed in so that the
front inputs are active. Wait at least three minutes before proceeding to allow for ther­mal equilibrium.

NOTE Be sure to connect the low-thermal short properly to the HI, LO, and SENSE termi-

nals. Keep drafts away from low-thermal connections to avoid thermal drift, which
could affect calibration accuracy.

2. Send the following command:

:CAL:PROT:DC:STEP1

3. After the Model 2700 completes this step, remove the low-thermal short, and then send
this command:

:CAL:PROT:DC:STEP2

NOTE Be sure to minimize movement near front Input terminals. Excessive movements can

cause capacitive coupling errors, which could affect calibration accuracy.

DC volts calibration

After the front panel short and open steps, do the following:

1. Connect the calibrator to the Model 2700 as shown in Figure 2-2. Allow three minutes
for thermal equilibrium.

NOTE Although 4-wire connections are shown, the sense leads are connected and discon-

nected at various points in this procedure by turning calibrator external sense on or
off as appropriate. If your calibrator does not have provisions for turning external
sense on and off, disconnect the sense leads when external sensing is to be turned off,
and connect the sense leads when external sensing is to be turned on.

Calibration 2-15

2. Perform the calibration steps summarized in Table 2-8. For each step:

• Set the calibrator to the indicated voltage, and make sure the unit is in operate.
(Use the recommended voltage if possible.)

• Send the indicated programming command. (Change the voltage parameter if you
are using a different calibration voltage.)

• Wait until the Model 2700 completes each step before continuing.

NOTE Ensure the calibrator has settled to the final value. You can do so by verifying that

the “Settled” indicator is off, or by using the *OPC? (operation complete) query.

Table 2-8

DC voltage calibration programming steps

Calibration step Calibrator voltage Calibration command* Parameter range

+10V

-10V
100V

*Use recommended value where possible. Change parameter accordingly if using a different calibrator voltage.

+10.00000V

-10.00000V

100.0000V

:CAL:PROT:DC:STEP3 10
:CAL:PROT:DC:STEP4 -10
:CAL:PROT:DC:STEP5 100

9 to 11

-9 to -11
90 to 110

Resistance calibration

Follow these steps for resistance calibration:

1. Set the calibrator to the resistance mode, and turn on external sensing.

NOTE Use external sense (4-wire Ω) when calibrating all resistance ranges. Be sure that

the calibrator external sense mode is turned on.

2. Perform the calibration steps summarized in Table 2-9. For each step:

• Set the calibrator to the indicated resistance, and make sure the unit is in operate.
(Use the recommended resistance or the closest available value.)

• Send the indicated programming command. (Change the command parameter if
you are using a different calibration resistance than that shown.)

• Wait until the Model 2700 completes each step before continuing.

Table 2-9

Resistance calibration programming steps

Calibration
step

Calibrator
resistance Calibration command* Parameter range

1kΩ
10kΩ
100kΩ
1MΩ

*Use exact calibrator resistance value for parameter.

1kΩ
10kΩ
100kΩ
1MΩ

:CAL:PROT:DC:STEP6 1E3
:CAL:PROT:DC:STEP7 10E3
:CAL:PROT:DC:STEP8 100E3
:CAL:PROT:DC:STEP9 1E6

900 to 1.1E3
9E3 to 11E3
90E3 to 110E3
900E3 to 1.1E6

2-16 Calibration

DC current calibration

After the 1MΩ resistance point has been calibrated, follow these steps for DC current

calibration:

1. Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as
shown in Figure 2-3.

2. Perform the calibration steps listed in Table 2-10. For each step:

• Set the calibrator to the indicated current, and make sure the unit is in operate.
(Use the recommended current if possible.)

• Send the indicated programming command. (Change the current parameter if you
are using a different calibration current.)

• Wait until the Model 2700 completes each step before continuing.

NOTE If you are performing DC-only calibration, proceed to “Programming calibration

dates.”

Table 2-10

DC current calibration programming steps

Calibration
step

10mA
100mA
1A

*Change parameter if using different current.

Calibrator
current Calibration command* Parameter range

10.00000mA

100.00000mA

1.000000A

:CAL:PROT:DC:STEP10 10E-3
:CAL:PROT:DC:STEP11 100E-3
:CAL:PROT:DC:STEP12 1

9E-3 to 11E-3
90E-3 to 110E-3

0.9 to 1.1

AC voltage calibration

Follow these steps for AC voltage calibration:

1. Connect the calibrator to the Model 2700 INPUT HI and LO terminals as shown in

Figure 2-4.

2. Perform the calibration steps summarized in Table 2-11. For each step:

• Set the calibrator to the indicated voltage and frequency, and make sure the unit is
in operate. (You must use the stated voltage and frequency.)

• Send the indicated programming command.

• Wait until the Model 2700 completes each step before continuing.

Calibration 2-17

Table 2-11

AC voltage calibration programming steps

Calibration step Calibrator voltage, frequency Calibration command

10mV AC at 1kHz
100mV AC at 1kHz
100mV AC at 50kHz
1VAC at 1kHz
1VAC at 50kHz
10VAC at 1kHz
10VAC at 50kHz
100VAC at 1kHz
100VAC at 50kHz
700VAC at 1kHz

10.00000mV, 1kHz

100.0000mV, 1kHZ

100.0000mV, 50kHz

1.000000V, 1kHz

1.000000V, 50kHz

10.00000V, 1kHz

10.00000V, 50kHz

100.0000V, 1kHz

100.0000V, 50kHz

700.000V, 1kHz

:CAL:PROT:AC:STEP1
:CAL:PROT:AC:STEP2
:CAL:PROT:AC:STEP3
:CAL:PROT:AC:STEP4
:CAL:PROT:AC:STEP5
:CAL:PROT:AC:STEP6
:CAL:PROT:AC:STEP7
:CAL:PROT:AC:STEP8
:CAL:PROT:AC:STEP9
:CAL:PROT:AC:STEP10

AC current calibration

Follow these steps for AC current calibration:

1. Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2700 as

shown in Figure 2-3.

2. Perform the calibration steps summarized in Table 2-12. For each step:

• Set the calibrator to the indicated current and frequency, and make sure the unit is
in operate. (You must use the stated current and frequency.)

• Send the indicated programming command.

• Wait until the Model 2700 completes each step before continuing.

Table 2-12

AC current calibration programming steps

Calibration step Calibrator current, frequency Calibration command

100mA at 1kHz
1A at 1kHz
2A at 1kHz

100.0000mA, 1kHz

1.000000A, 1kHz

2.000000A, 1kHz

:CAL:PROT:AC:STEP11
:CAL:PROT:AC:STEP12
:CAL:PROT:AC:STEP13

Programming calibration dates

Program the present calibration date and calibration due date by sending the following

commands:

:CAL:PROT:DATE <year>, <month>, <day>
:CAL:PROT:NDUE <year>, <month>, <day>

For example, the following commands assume calibration dates of 12/15/1999 and

12/15/2000 respectively:

:CAL:PROT:DATE 1999, 12, 15
:CAL:PROT:NDUE 2000, 12, 15

2-18 Calibration

Saving calibration constants

After completing the calibration procedure, send the following command to save the new

calibration constants:

:CAL:PROT:SAVE

NOTE Calibration constants will not be saved unless the :CAL:PROT:SAVE command is

sent.

Locking out calibration

After saving calibration, send the following command to lock out calibration:

:CAL:PROT:LOCK

Manufacturing calibration

The manufacturing calibration procedure is normally performed only at the factory, but the
necessary steps are included here in case the unit is repaired, and the unit requires these calibra­tion procedures.

NOTE If the unit has been repaired, the entire comprehensive calibration procedure should

also be performed in addition to the manufacturing calibration procedure.

Recommended test equipment

Table 2-13 summarizes the test equipment required for the manufacturing calibration steps.

In addition, you will need the calibrator (see Table 2-1) and signal generator to complete the
comprehensive calibration steps.

Table 2-13

Recommended equipment for manufacturing calibration

Stanford Research Systems DS345 Function Generator:

1V RMS, 3Hz, ±5ppm
1V RMS, 1kHz, ±5ppm

Keithley Model 2001 or 2002 Digital Multimeter:

1V, 3Hz AC, ±0.13%

Keithley 7797 Calibration/Extender Board

Keithley 7798-250B Calibration/Extender/Test Board

Extender board preparation

Before performing manufacturing calibration, short the output HI, LO, SHI, and SLO
terminals of the 7798-250B Calibration/Extender/Test Board together using clean, solid copper
wires. These connections will form a low-thermal short necessary for the manufacturing
calibration procedure. The Calibration Extender Test Board should then be installed in scanner
Slot #1.

Unlocking manufacturing calibration

To unlock manufacturing calibration, press and hold in the OPEN key while turning on the
power.

Measuring function generator signal amplitude

The 3Hz function generator signal amplitude must be accurately measured using the digital
multimeter listed in Table 2-13. Proceed as follows:

1. Connect the function generator output to the digital multimeter INPUT jacks. (See

Figure 2-5 for typical connections.)

2. Turn on the function generator and multimeter, and allow a two-hour warm-up period
before measuring.

3. Set the function generator to output a 1V RMS sine wave at 3Hz; measure and record
the signal amplitude.

Calibration 2-19

2-20 Calibration

Front panel manufacturing calibration

1. Install the shorted calibration extender board (see “Extender board preparation” earlier
in this section) in scanner card Slot 1, and select the rear inputs with the INPUTS
switch. Allow three minutes for thermal equilibrium.

2. Press in and hold the OPEN key while turning on the power.

3. Press SHIFT then TEST. then display CALIB: TEST with the up or down range key.
Press ENTER, select RUN, then enter the appropriate calibration code (default:

002700).

4. Select ALL at the CAL:RUN prompt.

5. Press ENTER to perform the first manufacturing calibration step.

6. Perform the entire front panel comprehensive calibration procedure discussed earlier in
this section. (See “Comprehensive calibration” earlier in this section.)

7. Connect the function generator to the Model 2700 front panel INPUT jacks as shown in

Figure 2-5. Select the front input jacks with the INPUTS switch.

Figure 2-5

Function generator connections for manufacturing calibration

BNC-to-Dual

Banana Plug

Adapter

Model 2700

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

LOCAL

POWER

Model 2700 Multimeter / Data Acquisition System

CONT

RECALL

CH AVG

OCOMP

PERIOD SENSOR

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

FREQ

TEMP

RANGE

CH-OFF CARD

GPIB

EXIT ENTER

AUTO

RANGE

RS-232

RELFILTER

ACI

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

DCI

HOLD

LIMITS ON/OFFDELAY

EX TRIG

TRIG

STORE

SAVE SETUP

CONFIG HALT

CLOSE

OPEN

STEP SCAN

F

FRONT/REAR

INPUTS

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

50Ω

Cable

Function Generator

Function

Output

Note: Output voltage must be accurately measured.

(See text).

8. After the last AC current calibration step, the instrument will prompt you to enter 3Hz
at 1V RMS and 1kHz with the following prompts:

• Low-frequency cal: Set the function generator to output a 1V RMS, 3Hz sine
wave. Use the left and right arrow keys, and the range keys to adjust the display to
agree with the generator amplitude you measured previously, then press ENTER.

• Frequency cal: Set the function generator to output a 1V RMS, 1kHz sine wave.
Enter 1.000000kHz at the prompt, then press ENTER.

9. Set the calibration dates, then save calibration to complete the process.

Remote manufacturing calibration

1. Install the shorted calibration extender board (see “Extender board preparation” earlier

in this section) in scanner card Slot 1, and select the rear inputs with the INPUTS
switch. Allow three minutes for thermal equilibrium.

2. Press in and hold the OPEN key while turning on the power.

3. Enable calibration by sending the :CODE command. For example, the default com-

mand is:

:CAL:PROT:CODE 'KI002700'

4. Initiate calibration by sending the following command:

:CAL:PROT:INIT

5. Calibrate step 0 with the following command:

:CAL:PROT:DC:STEP0

6. Perform the entire remote comprehensive calibration procedure discussed earlier in this

section. (See “Comprehensive calibration” earlier in this section.)

7. Connect the function generator to the Model 2700 INPUT jacks as shown in Figure 2-5.

Select the front input jacks with the INPUTS switch.

8. Set the generator to output a 1V RMS, 3Hz sine wave, then send the following com-

mand:

:CAL:PROT:AC:STEP14 <Cal_voltage>

Here <Cal_voltage> is the actual 3Hz generator signal amplitude you measured
previously.

9. Set the generator to output a 1V RMS, 1kHz sine wave, then send the following

command:

:CAL:PROT:AC:STEP15 1E3

10. Send the following commands to set calibration dates, save calibration, and lock out
calibration:

:CAL:PROT:DATE <year>, <month>, <day>

:CAL:PROT:NDUE <year>, <month>, <day>

:CAL:PROT:SAVE

:CAL:PROT:LOCK

Calibration 2-21

2-22 Calibration

Model 7700 calibration

The following procedures calibrate the temperature sensors on the Model 7700 plug-in

modules.

NOTE For additional information about the Keithley modules, refer to the appropriate

appendix in the Model 2700 User’s Manual.

Recommended test equipment

In order to calibrate the Model 7700, you will need equipment summarized in Table 2-14.

Table 2-14

Recommended equipment for Model 7700 calibration

Digital Thermometer:

18 to 28˚C, ±0.1˚C

Keithley 7797 Calibration/Extender Board

Extender board connections

The Model 7700 being calibrated should be connected to the 7797 Calibration/Extender
Board, and the extender board should then be installed in scanner Slot #1. Note that the module
being calibrated will be external to the Model 2700 to avoid card heating during calibration.

Model 7700 calibration

NOTE Before calibrating the Model 7700, make sure that power has been removed from the

card for at least two hours to allow card circuitry to cool down. After turning on the
power during the calibration procedure, complete the procedure as quickly as possi­ble to minimize card heating that could affect calibration accuracy. Allow the
Model 2700 to warm up for at least two hours.

Front panel Model 7700 calibration

1. Connect the Model 7700 to the Model 7797 Calibration/Extender Board (see “Extender
board connections” above).

2. With the power off, install the Model 7700/7797 combination in Slot 1, and select the
rear inputs with the INPUTS switch. Allow three minutes for thermal equilibrium.

3. Accurately measure and record the cold temperature of the Model 7700 card surface at
the center of the card with an RTD sensor.

4. Press in and hold the Model 2700 OPEN key while turning on the power.

Calibration 2-23

5. Press SHIFT then TEST, then display TEST:CALIB with the up or down range key.
Press ENTER, select RUN, then enter the appropriate calibration code (default:

002700).

6. Using the up or down range key, select CARD at the CAL:RUN prompt, then press
ENTER.

7. Set the display value to the cold calibration temperature (˚C) you measured in Step 3,
then press ENTER to complete Model 7700 calibration.

Remote Model 7700 calibration

1. Connect the Model 7700 to the 7797 Calibration/Extender Board (see “Extender board
connections” above).

2. With the power off, install the Model 7700/7797 combination in Slot 1, and select the
rear inputs with the INPUTS switch. Allow three minutes for thermal equilibrium.

3. Accurately measure and record the cold temperature of the Model 7700 card surface at
the center of the card.

4. Press in and hold the Model 2700 OPEN key while turning on the power.

5. Enable calibration by sending the :CODE command. For example, the default com­mand is:

:CAL:PROT:CODE 'KI002700'

6. Initiate calibration by sending the following command:

:CAL:PROT:CARD1:INIT

7. Calibrate the Model 7700 with the following command:

:CAL:PROT:CARD1:STEP0 <temp>

Here <temp> is the cold calibration temperature (˚C) measured in Step 3.

8. Send the following commands to save calibration and lock out calibration:

:CAL:PROT:CARD1:SAVE

:CAL:PROT:CARD1:LOCK

2-24 Calibration

3

Routine Maintenance

3-2 Routine Maintenance

Introduction

The information in this section deals with routine type maintenance and includes procedures
for setting the line voltage, replacing the Model 2700 line and front terminal AMPS fuses, and
replacing the amps fuses for the Models 7700 and 7702 plug-in modules. Replacement of the
Model 2700 non-volatile RAM battery is also covered.

Setting the line voltage and replacing the line fuse

WARNING Disconnect the line cord at the rear panel, and remove all test leads con-

nected to the instrument (front and rear) before replacing the line fuse.

The power line fuse is located in the power module next to the AC power receptacle (see

Figure 3-1). If the line voltage must be changed, or if the line fuse requires replacement, per-

form the following steps:

1. Place the tip of a flat-blade screwdriver into the power module by the fuse holder
assembly (see Figure 3-1). Gently push in and to the left. 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 3-1.

CAUTION For continued protection against fire or instrument damage, replace the

fuse only 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 inverted in the window.

CAUTION Operating the Model 2700 on the wrong line voltage may result in instru-

ment damage.

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

Routine Maintenance 3-3

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

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

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

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

Fi

1

P

gure 3-

ower module

DIGITAL I/O TRIG. LINK

Table 3-1

Power line fuse

!

Model 2700

RS232

MADE IN

U.S.A.

IEEE-488

SLT

1

SLT

2

!

Line Voltage Selector

Fuse

220

240

0
0

120

1

Spring

Window

Fuse Holder Assembly

Line Voltage Rating Keithley Part No.

100/120V 1/2A, 250V, 5 × 20 mm, slow-blow FU-71

200/240V 1/4A, 250V, 5 × 20 mm, slow-blow FU-96-4

3-4 Routine Maintenance

Fi

2

F
A

Replacing the front terminal AMPS fuse

The front terminal AMPS fuse protects the Model 2700 current input from an over-current

condition. Follow the steps below to replace the AMPS fuse.

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

equipment before replacing the AMPS fuse.

1. Turn off the power, and disconnect the power line and test leads.

2. From the front panel, gently push in the AMPS jack with your thumb, and rotate the
fuse carrier one-quarter turn counterclockwise. (See Figure 3-2.) Release pressure on
the jack, and its internal spring will push the fuse carrier out of the socket.

3. Remove the fuse, and replace it with the same type: 3A, 250V, fast-blow, Keithley part
number FU-99-1.

CAUTION Do not use a fuse with a higher current rating than specified or instrument

damage may occur. If the instrument repeatedly blows fuses, locate and
correct the cause of the trouble before replacing the fuse.

4. Install the new fuse by reversing the above procedure.

gure 3-

ront terminal
MPS fuse

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

OUTPUT

ACV

HOLD

TRIG

CLOSE

Model 2700

Model 2700 Multimeter / Data Acquisition System

CONT

CH AVG

RECALL

OCOMP

ACI

Ω2 Ω4

MONITOR

TYPE

RELFILTER

LSYNC

TEST

DIGITS RATE

RATIO

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

PERIOD SENSOR

FREQ

TEMP

CH-OFF

CARD

RS-232

GPIB

EXIT ENTER

Integra Series

RANGE

AUTO

RANGE

PEAK

350V

SENSE

Ω 4 WIRE

INPUTS

F

FRONT/REAR

INPUT

HI

1000V

!

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

Push in AMPS

and Rotate

Counterclockwise

Replacing plug-in module amps fuses

NOTE The following procedures apply only to the Model 7700 and 7702 plug-in modules.

WARNING The information in this section is intended only for qualified service per-

sonnel. Do not perform these procedures unless you are qualified to do so.

Make sure that all plug-in module connections are de-energized and dis­connected before replacing module amps fuses.

Replacing Model 7700 amps fuses

1. Turn off the power, and disconnect the power line and external connections from the
Model 7700.

2. Open the Model 7700 top cover.

3. Locate the amps fuses for CH21 and CH22 (see Figure 3-3).

4. Remove the circuit board from the bottom plastic housing by removing the two bottom
screws.

Figure 3-3

Model 7700 amps fuses

Routine Maintenance 3-5

CH22 Fuse

Model 7700

INPUT SENSE

HLHL

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

CH1
HLHL

LO

AMPS

HLHL

HLHL

HLHLHLHLHLHL

CH6

CH5

CH4

CH3

CH2

CH21 Fuse

CH7 CH8 CH9 CH10

HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

3-6 Routine Maintenance

5. De-solder the blown CH21 or CH22 fuse as required, taking care not to damage the cir­cuit board or spread solder flux around the board.

6. Install a new 3A, 250V fast-blow fuse, Keithley part number FU-107-1.

CAUTION Do not use a fuse with a higher current rating than specified or module

7. Solder the new fuse in place using organic (OA based) flux solder, again taking care not
to damage the circuit board or spread solder flux around the board.

8. Carefully clean the repaired area of the circuit board with a foam tipped swab or brush
dipped in pure water, then blow dry the board with dry nitrogen gas. Allow the board to
dry for several hours in a 50˚C low-humidity environment before use.

9. Re-install the circuit board into the plastic housing, then close the top cover.

Replacing Model 7702 amps fuses

1. Turn off the power, and disconnect the power line and external connections from the
Model 7702.

2. Open the Model 7702 top cover.

3. Locate the amps fuses for CH41 and CH42 (see Figure 3-4).

4. Remove the circuit board from the bottom plastic housing by removing the two bottom
screws.

5. De-solder the blown CH41 or CH42 fuse as required, taking care not to damage the cir­cuit board or spread solder flux around the board.

6. Install a new 3A, 250V fast-blow fuse, Keithley part number FU-107-1.

damage may occur.

CAUTION Do not use a fuse with a higher current rating than specified or module

damage may occur.

7. Solder the new fuse in place using organic (OA based) flux solder, again taking care not
to damage the circuit board or spread solder flux around the board.

8. Carefully clean the repaired area of the circuit board with a foam tipped swab or brush
dipped in pure water, then blow dry the board with dry nitrogen gas. Allow the board to
dry for several hours in a 50˚C low-humidity environment before use.

9. Re-install the circuit board into the plastic housing, then close the top cover.

Figure 3-4

Model 7702 amps fuses

Routine Maintenance 3-7

Model 7702

TE122

TE121

CH42 FuseCH41 Fuse

3-8 Routine Maintenance

Replacing non-volatile RAM battery

The Model 2700 has a three year battery for non-volatile RAM. Use the procedure below to
replace the battery, if required. Refer to the disassembly procedures in Section 5 and the parts
list and component layout drawings at the end of Section 6 for more information.

WARNING The following procedure is intended only for qualified service personnel.

Do not perform this procedure unless you are qualified to do so.

Disconnect the line cord and all connecting wires from the Model 2700
before removing the top cover.

1. Before replacing the battery, refer to the troubleshooting procedures in Table 4-4 in
Section 4 to determine if the battery requires replacement

2. Remove the Model 2700 top cover using the disassembly procedures in Section 5.

3. Locate battery BT100 using the motherboard component layout drawing at the end of
Section 6.

4. De-solder the battery from the top side of the circuit board.

5. Install a new battery, Keithley part number BA-51, taking care to observe proper
polarity.

6. Solder the battery connection to the circuit board using organic (OA-based) flux solder.

7. After soldering, remove all flux using a foam-tipped swab or brush dipped in pure
water. Blow dry the board with dry nitrogen gas, then allow the board to dry for several
hours in a 50˚C, low-humidity environment before use.

8. Re-install the top cover by following the disassembly procedures in Section 5 in reverse
order.

4

Troubleshooting

4-2 Troubleshooting

Introduction

This section of the manual will assist you in troubleshooting and repairing the Model 2700.
Included are self-tests, test procedures, troubleshooting tables, and circuit descriptions. It is left
to the discretion of the repair technician to select the appropriate tests and documentation
needed to troubleshoot the instrument. Refer to the disassembly procedures in Section 5 and
the parts lists in Section 6 for further information.

WARNING The information in this section is intended only for qualified service per-

sonnel. Do not perform these procedures unless you are qualified to do so.
Some of these procedures may expose you to hazardous voltages that could
cause personal injury or death. Use caution when working with hazardous
voltages.

Repair considerations

Before making any repairs to the Model 2700, be sure to read the following considerations.

CAUTION The PC boards are built using surface mount techniques and require spe-

cialized equipment and skills for repair. If you are not equipped and/or
qualified, it is strongly recommended that you send the unit back to the
factory for repairs or limit repairs to the PC board replacement level.
Without proper equipment and training, you could damage a PC board
beyond repair.

• Repairs will require various degrees of disassembly. However, it is recommended that
the Front Panel Tests be performed prior to any disassembly. The disassembly instruc­tions for the Model 2700 are contained in Section 5 of this manual.

• Do not make repairs to surface mount PC boards unless equipped and qualified to do so
(see previous CAUTION).

• When working inside the unit and replacing parts, be sure to adhere to the handling pre­cautions and cleaning procedures explained in Section 5.

• Many CMOS devices are installed in the Model 2700. These static-sensitive devices
require special handling as explained in Section 5.

• Whenever a circuit board is removed or a component is replaced, the Model 2700 must
be recalibrated. See Section 2 for details on calibrating the unit.

Power-on self-test

During the power-on sequence, the Model 2700 will perform a checksum test on its EPROM
(U156 and U157) and test its RAM (U151 and U152). If one of these tests fails, the instrument
will lock up.

Front panel tests

There are two front panel tests: one to test the functionality of the front panel keys and one
to test the display. In the event of a test failure, refer to “Display board checks” for details on
troubleshooting the display board.

KEY test

The KEY test allows you to check the functionality of each front panel key. Perform the fol­lowing steps to run the KEY test:

1. Press SHIFT and then TEST to access the self-test options.

2. Use the up or down RANGE key to display “TEST: KEY”.

3. Press ENTER to start the test. When a key is pressed, the label name for that key is dis­played to indicate that it is functioning properly. When the key is released, the message
“NO KEY PRESS” is displayed.

4. Pressing EXIT tests the EXIT key. However, the second consecutive press of EXIT
aborts the test and returns the instrument to normal operation.

DISP test

Troubleshooting 4-3

The display test allows you to verify that each segment and annunciator in the vacuum fluo-

rescent display is working properly. Perform the following steps to run the display test:

1. Press SHIFT and then TEST to access the self-test options.

2. Use the up or down RANGE key to display “TEST: DISP”.

3. Press ENTER to start the test. There are four parts to the display test. Each time
ENTER is pressed, the next part of the test sequence is selected. The four parts of the
test sequence are as follows:

a. All annunciators are displayed.

b. The segments of each digit are sequentially displayed.

c. The 12 digits (and annunciators) are sequentially displayed.

d. The annunciators located at either end of the display are sequentially displayed.

4. When finished, abort the display test by pressing EXIT. The instrument returns to nor­mal operation.

4-4 Troubleshooting

Principles of operation

The following information is provided to support the troubleshooting tests and procedures

covered in this section of the manual. Refer to the following block diagrams:

Figure 4-1 — Power supply block diagram

Figure 4-2— Digital circuitry block diagram

Figure 4-3 — Analog circuitry block diagram

Power supply

The following information provides some basic circuit theory that can be used as an aid to

troubleshoot the power supply. A block diagram of the power supply is shown in Figure 4-1.

Figure 4-1

Power supply block diagram

Fuse

Power

Switch

Line

Voltage

Select

Switch

Power

Transformer

CR104
C156, C175
C281, U144

CR116, CR117

C104, U101

CR102, CR115

C131, C148

U119, U125

CR103

C146
U124

+5VD

D Common

+37V

D Common

+18V
+15.7V

A Common

-15.7V

-18V

+5V

A Common

Troubleshooting 4-5

AC power is applied to the AC power module receptacle. Power is routed through the line
fuse and line voltage selection switch of the power module to the power transformer. The
power transformer has a total of four secondary windings for the various supplies.

AC voltage for the display filaments is taken from a power transformer secondary at F1 and
F2, and then routed to the display board.

Each DC supply uses a rectifier and a capacitive filter, and many supplies use an IC regula­tor. Table 4-1 summarizes rectifier, filter, and regulator circuits for the various DC supplies.

Table 4-1

Power supply components

Supply Rectifier Filter Regulator

+5VD
+37V
+15.7V

-15.7V
+5V, +5VRL, +5V2
+18V

-18V

CR104
CR116, CR117
CR102, CR115
CR102, CR115
CR103
CR102
CR102

C128, C156, C175, C281
C104
C148
C131
C146
C148
C131

U144
U101
U125
U119
U124

-

-

4-6 Troubleshooting

Display board

Display board components are shown in the digital circuitry block diagram in Figure 4-2.

Figure 4-2

Digital circuitry block diagram

Analog

Circuitry

(See Figure 4-3)

U127
U173
U174

XADTX

XADCLK

XADTS

XADRX

Slot
Control

O

P
T

O

I

S

O

AT101

U150
U155

Line Sync

Control

U179
U180
U181
U182
U183
U184
U186

Trigger

U146, U164

Trigger

Link

NVRAM

U136

ADCLK

ADRXB

TRIG IN

TRIG OUT

ADTX

ADTS

ROM

U156, U157

68306

µP

U135

IN
OUT

Data IN

Data OUT

Data Bus

BAT

BT100

RAM

U151, U152

Display Board

Controller

XTAL
Y101

RS-232

U159

U158, U160,

Digital Output

U122, U188

Digital Input

U146, U191

U401

GPIB

U161

U189

U192

Battery

Back

Control/

Realtime Clock

U171

Keypad

Display

DS401

RS-232

Port

IEEE-488

Digital

I/O

Y103

Bus

Microcontroller

U401 is the display board microcontroller that controls the display and interprets key data.
The microcontroller uses three internal peripheral I/O ports for the various control and read
functions.

Display data is serially transmitted to the microcontroller from the digital section via the
TXB line to the microcontroller RDI terminal. In a similar manner, key data is serially sent
back to the digital section through the RXB line via TDO. The 4MHz clock for the microcon­troller is generated by crystal Y401.

Display

DS401 is the display module, which can display up to 12 alpha-numeric characters and

includes the various annunciators.

The display uses a common multiplexing scheme with each character refreshed in sequence.
U402 and U403 are the drivers for the display characters and annunciators. Note that data for
the drivers are serially transmitted from the microcontroller (MOSI and PC1).

Filament voltage for the display is derived from the power supply transformer (F1 and F2).
The display drivers require +37VDC and +5VDC, which are supplied by U144 (+5VD) and
U101 (+37V).

Key matrix

The front panel keys (S401-S430) are organized into a row-column matrix to minimize the
number of microcontroller peripheral lines required to read the keyboard. A key is read by
strobing the columns and reading all rows for each strobed column. Key-down data is inter­preted by the display microcontroller and sent back to the main microprocessor using propri­etary encoding schemes.

Digital circuitry

Troubleshooting 4-7

Refer to Figure 4-2 for the following discussion on digital circuitry.

Microprocessor

U135 is a 68306 microprocessor that oversees all operating aspects of the instrument. The
MPU has a 16-bit data bus and provides an 19-bit address bus. It also has parallel and serial
ports for controlling various circuits. For example, the RXDA, TXDA, RXDB and TXDB lines
are used for the RS-232 interface.

The MPU clock frequency of 14.7456MHz is controlled by crystal Y101. MPU RESET is
performed momentarily on power-up.

Memory circuits

ROMs U156 and U157 store the firmware code for instrument operation. U157 stores the
D0-D7 bits of each data word, and U156 stores the D8-D15 bits.

RAMs U151 and U152 provide battery backed operating storage. U152 stores the D0-D7
bits of each data word, and U151 stores the D8-D15 bits.

Semi-permanent storage facilities include NVRAM U136. This IC stores such information
as instrument setup and calibration constants. Data transmission from this device is done in a
serial fashion.

U171, Y103, and BT100 make up the battery watchdog control, along with the real-time
clock. U171 automatically senses when the +5VD supply is being powered down and then
switches to BT100 for power.

4-8 Troubleshooting

RS-232 interface

Serial data transmission and reception is performed by the TXDB and RXDB lines of the

MPU. U159 provides the necessary voltage level conversion for the RS-232 interface port.

IEEE-488 interface

U158, U160, and U161 make up the IEEE-488 interface. U158, a 9914A GPIA, takes care
of routine bus overhead such as handshaking, while U160 and U161 provide the necessary
buffering and drive capabilities.

Trigger circuits

Buffering for Trigger Link input and output is performed by U146. Trigger input and output
is controlled by the IRQ4 and PB3 lines of the MPU. U164 provides additional logic for the
trigger input to minimize MPU control overhead.

Digital I/O

U146, U191, and U192 make up the digital input circuitry. External triggering can occur on
J1006 or J1007. U192 allows hardware handshaking to external controllers by gating off
triggers.

U122, U188, and U189 provide digital output. U122 is a shift register that feeds updated
output information to the two driver ICs, U188 and U189, which provide current sink capabil­ity of 100mA each.

Module slot control

U127, U173, and U174 make up the control circuitry that allows communication of relay
data to Slot 1 or Slot 2.

Line sync

U179, U180, U181, U182, U183, and U186 are used to control A/D triggers synchronized at
the zero cross point of the power line voltage. U186 controls zero crossing detection, while
U182 and U183 preserve the trigger states until the zero crossing threshold is detected.

Analog circuitry

Refer to Figure 4-3 for the following discussion on analog circuitry.

Figure 4-3

Analog circuitry block diagram

Front Terminals

S101

Troubleshooting 4-9

Front Terminals

S101

Scanner Outputs

Front Terminals

S101

Scanner Outputs

Front Terminals

S101

Scanner Outputs

Scanner Outputs

INPUT

HI

SENSE

HI

SENSE

LO

Scanner Outputs

AMPS

Divider
R117, Q109,
Q114, Q136

Scanner

Inputs

DCV

R163, Q122, Q135,

Current

Shunts

K103, R158,

R205, R338

K101

SSP*

Q101, Q102

DCV/100

Protection

R120, R121, R124,

R125, Q107, Q148,

VR119, VR120

Protection

R132, R139, R148,

VR119, VR120

Slot 1

DCA

ACA

AC Switching

&

Gain

K102, U102, U103, U105,

U112, U118, U111, U110

ACV,

FREQ

DCV

OHMS

Q120, CR114

Ohms I-Source

Q119, Q123,

Q124, Q125, Q126,

U123, U133

Slot

Control

DCV & Ohms

Switching
Q104, Q105
Q108, Q113

X1
Buffer
U113

BUFCOM

A/D

MUX &

Gain
U129, U132
U163, U166

X1
Buffer
U167

ADC

U165

Digital

Circuitry

(See Figure 4-2)

Scanner

Inputs

Slot 2

* Solid State Protection

INPUT HI

INPUT HI protection is provided by the SSP (Solid State Protection) circuit. The SSP is pri­marily made up of Q101 and Q102. An overload condition opens Q101 and Q102, which dis­connects the analog input signal from the rest of the analog circuit.

Note that for the 100VDC and 1000VDC ranges, Q101 and Q102 of the SSP are open. The
DC voltage signal is routed through the DCV Divider (Q114 and Q136 on) to the DCV switch­ing circuit.

4-10 Troubleshooting

AMPS input

The ACA or DCA input signal is applied to the Current Shunt circuit, which is made up of
K103, R158, R205, and R338. For the 20mA DC range, 5.1Ω (R205/[R338 + R158]) is
shunted across the input. Relay K103 is energized (set state) to select the shunts. For all other
DCA ranges, and all ACA ranges, 0.1Ω (R158) is shunted across the input (K103 reset).

The ACA signal is then sent to the AC Switching & Gain circuit, while the DCA signal is
routed directly to the A/D MUX & Gain circuit.

Signal switching

Signal switching for DCV and OHMS is done by the DCV & Ohms Switching circuit. FETs
Q113, Q105, Q104, and Q108 connect the DCV or ohms signal to the X1 buffer (U113).

Note that the reference current for OHMS is generated by the Ohms I-Source circuit. For
4-wire ohms measurements, SENSE LO is connected to U126.

Signal switching and gain for ACV, FREQ and ACA is done by the AC Switching & Gain
circuit, which is primarily made up of K102, U102, U103, U105, U112, U118, U111, and
U110. Note that U111 is used for frequency adjustment. The states of these analog switches
vary from unit to unit.

Multiplexer and A/D converter

All input signals, except FREQ, are routed to the A/D MUX & Gain circuit. The multiplexer
(U163) switches the various signals for measurement. In addition to the input signal, the multi­plexer also switches among reference and zero signals at various phases of the measurement
cycle.

When the input signal is selected by the MUX, it is amplified by U132 and U166. Gain is
controlled by switches in U129 and associated resistors.

The multiplexed signals of the measurement cycle are routed to the A/D Converter (U165)
where it converts the analog signals to digital form. The digital signals are then routed through
an opto-isolator to the MPU to calculate a reading.

Scanner card signals

Scanner card input signals are connected directly to installed scanner cards. Scanner card
output signals are routed internally to the INPUTS switch, which selects between the front
panel terminals and the scanner card outputs.

Troubleshooting

Troubleshooting information for the various circuits is summarized below. See “Principles

of operation” for circuit theory.

Display board checks

If the front panel DISP test indicates that there is a problem on the display board, use

Table 4-2.

Table 4-2

Display board checks

Step Item/component Required condition Remarks

Troubleshooting 4-11

Front panel DISP test

1

P1005, PIN 5

2

P1005, PIN 9

3

U401, PIN 1

4

U401, PIN43

5

U401, PIN 32

6

U401, PIN 33

7

Verify that all segments operate.
+5V ±5%
+37V ±5%
Goes low briefly on power up, then

goes high.
4MHz square wave.
Pulse train every 1msec.
Brief pulse train when front panel

key is pressed.

Use front panel display test.
Digital +5V supply.
Display +37V supply.
Microcontroller RESET.

Controller 4MHz clock.
Control from main processor.
Key down data sent to main processor.

Power supply checks

Power supply problems can be checked using Table 4-3.

Table 4-3

Power supply checks

Step Item/component Required condition Remarks

Line fuse

1

Line voltage

2

Line power

3

U144, pin 3

4

U101, pin 7

5

U125, pin 3

6

U119, pin 3

7

U124, pin 3

8

1

TP106

2

C148 negative terminal

Check continuity.
120V/240V as required.
Plugged into live receptacle, power on.
+5V ±5%
+37V ±5%
+15.7V ±5%

-15.7V ±5%
+5V ±5%

Remove to check.
Check power module position.
Check for correct power-up sequence.
+5VD, referenced to Common D.
+37V, referenced to Common D.
+15V, referenced to Common A.

-15V, referenced to Common A.
+5VRL, referenced to Common A.

1

1

2

2

2

4-12 Troubleshooting

Digital circuitry checks

Digital circuit problems can be checked using Table 4-4.

Table 4-4

Digital circuitry checks

Step Item/component Required condition Remarks

Power-on test

1

U152, pin 16

2

U171, pin 16

3

U171, pin 15

4

U171, pin 4

5

U135, pin 48

6

U135, lines A1-A19

7

U135, lines D0-D15

8

U135, pin 44

9

U159, pin 13

10

U159, pin 14

11

U158, pins 34-42

12

U158, pins 26-31

13

U158, pin 24

14

U158, pin 25

15

U135, pin 84

16

U135, pin 91

17

U135, pin 90

18

U135, pin 89

19

RAM OK, ROM OK.
Digital common.
+5V (+5VD supply).
+5V (+5VB supply).
+3V
Low on power-up, then goes high.
Check for stuck bits.
Check for stuck bits.

14.7456MHz
Pulse train during RS-232 I/O.
Pulse train during RS-232 I/O.
Pulse train during IEEE-488 I/O.
Pulses during IEEE-488 I/O.
Low with remote enabled.
Low during interface clear.
Pulse train.
Pulse train.
Pulse train.
Pulse train.

Verify that RAM and ROM are functional.
All signals referenced to digital common.
Digital logic supply.
Battery backed memory supply.
Battery voltage (BT100).
MPU RESET line.
MPU address bus.
MPU data bus.
MPU clock.
RS-232 RX line.
RS-232 TX line.
IEEE-488 data bus.
IEEE-488 command lines.
IEEE-488 REN line.
IEEE-488 IFC line.
ADRXB
ADTX
ADCLK
ADTS

Troubleshooting 4-13

Analog signal switching states

Table 4-5 through Table 4-11 provide switching states of the various relays, FETs, and ana-

log switches for the basic measurement functions and ranges. These tables can be used to assist
in tracing an analog signal from the input to the A/D multiplexer.

Table 4-5

DCV signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108

100mV
1V
10V
100V
1000V

* K101 set states: Pin 8 switched to Pin 7

ON
ON
ON
OFF
OFF

ON
ON
ON
OFF
OFF

Pin 3 switched to Pin 4

OFF
OFF
OFF
ON
ON

OFF
OFF
OFF
ON
ON

Table 4-6

ACV and FREQ signal switching

U103

Range Q101 Q102 K101* K102*

100mV
1V
10V
100V
750V

* K101 and K102 reset states: Pin 8 switched to Pin 9

ON

RESET

ON

ON

RESET

ON

ON

RESET

ON

ON

RESET

ON

ON

K101 and K102 set states: Pin 8 switched to Pin 7

RESET

ON

RESET
RESET
SET
SET
SET

Pin 3 switched to Pin 2

Pin 3 switched to Pin 4

pin 8

ON
ON
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF

U103
pin 9

ON
ON
OFF
OFF
OFF

SET
SET
SET
SET
SET

U105
pin 9

OFF
OFF
ON
ON
ON

OFF
OFF
OFF
OFF
OFF

U105
pin 8

OFF
OFF
OFF
OFF
ON

OFF
OFF
OFF
OFF
OFF

U103
pin 16

OFF
ON
OFF
ON
OFF

U103
pin 1

ON
OFF
ON
OFF
OFF

ON
ON
ON
OFF
OFF

U105
pin 1

ON
OFF
ON
OFF
OFF

OFF
OFF
OFF
ON
ON

U111
pin 16

OFF
OFF
OFF
OFF
OFF

4-14 Troubleshooting

Table 4-7

Ω2 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* K102* Q113 Q105 Q104 Q108

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

* K101 set states: Pin 8 switched to Pin 7

K102 reset states: Pin 8 switched to Pin 9

ON
ON
ON
ON
ON
ON
ON

ON
ON
ON
ON
ON
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF

Pin 3 switched to Pin 4

Pin 3 switched to Pin 2

OFF
OFF
OFF
OFF
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF
ON
ON

SET
SET
SET
SET
SET
SET
SET

RESET
RESET
RESET
RESET
RESET
RESET
RESET

OFF
OFF
OFF
OFF
OFF
OFF
OFF

ON
ON
ON
ON
ON
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF
OFF
OFF

Table 4-8

Ω4 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

* K101 set states: Pin 8 switched to Pin 7

ON
ON
ON
ON
ON
ON
ON

ON
ON
ON
ON
ON
ON
ON

Pin 3 switched to Pin 4

OFF
OFF
OFF
OFF
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF
ON
ON

SET
SET
SET
SET
SET
SET
SET

ON
ON
ON
ON
ON
OFF
OFF

OFF
OFF
OFF
OFF
OFF
ON
ON

OFF
OFF
OFF
OFF
OFF
OFF
OFF

OFF
OFF
OFF
OFF
OFF
OFF
OFF

Table 4-9

Ω2/Ω4 reference switching

Range U133/0.7V U133/7V Q123 Q125 Q124 Q126 Q120

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

OFF
OFF
OFF
ON
ON
OFF
OFF

ON
ON
ON
OFF
OFF
ON
ON

ON
ON
OFF
OFF
OFF
OFF
OFF

ON
ON
OFF
OFF
OFF
OFF
OFF

OFF
OFF
ON
ON
ON
ON
ON

OFF
OFF
ON
ON
ON
ON
ON

ON
ON
ON
ON
ON
OFF
OFF

Table 4-10

DCA signal switching

Range K103

Troubleshooting 4-15

20mA
100mA
1A
3A

K103 set states: Pin 8 to 7

K103 reset states: Pin 8 to 9

Set
Reset
Reset
Reset

Pin 3 to 4

Pin 3 to 2

Table 4-11

ACA signal switching

Range K103

1A
3A

K103 set states: Pin 8 to 7

K103 reset states: Pin 8 to 9

Reset
Reset

Pin 3 to 4

Pin 3 to 2

U105
pin 16

ON
ON

U105
pin 1

ON
ON

U111
pin 16

OFF
ON

U105
pin 8

OFF
OFF

U103
pin 16

OFF
OFF

U103
pin 1

OFF
OFF

4-16 Troubleshooting

Table 4-12 through Table 4-16 can be used to trace the analog signal through the A/D multi-

plexer (U163) to the final amplifier stage. These tables show the MUX lines (S3, S4, S6, S7)
that are selected for measurement during the SIGNAL phase of the multiplexing cycle. Also
included are switching states of analog switches (U129) that set up the gain for the final ampli­fier stage (U166).

Table 4-12

DCV signal multiplexing and gain

Range

100mV
1V
10V
100V
1000V

Signal
(U163)

S4
S4
S4
S4
S4

U129
pin 1

OFF
OFF
ON
OFF
ON

U129
pin 8

OFF
ON
OFF
ON
OFF

U129
pin 9

ON
OFF
OFF
OFF
OFF

Table 4-13

ACV and ACA signal multiplexing and gain

Range

Signal
(U163)

U129
pin 1

U129
pin 8

U129
pin 9

All S3 ON OFF OFF ×1

Table 4-14

DCA signal multiplexing and gain

Range

Signal
(U163)

U129
pin 1

U129
pin 8

U129
pin 9

Gain
(U166)

×100
×10
×1
×10
×1

Gain
(U166)

Gain
(U166)

20mA
100mA
1A
3A

S6
S6
S6
S6

OFF
OFF
OFF
OFF

OFF
OFF
OFF
ON

ON
ON
ON
OFF

×100
×100
×100
×10

Table 4-15

Ω2 signal multiplexing and gain

Troubleshooting 4-17

Range

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

Signal
(U163)

S4
S4
S4
S4
S4
S4
S4

U129
pin 1

OFF
OFF
OFF
OFF
ON
ON
ON

Table 4-16

Ω4 signal multiplexing and gain

Range

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

Signal
(U163)

S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7

U129
pin 1

OFF
OFF
OFF
OFF
ON
ON
ON

U129
pin 8

OFF
ON
ON
ON
OFF
OFF
OFF

U129
pin 8

OFF
ON
ON
ON
OFF
OFF
OFF

U129
pin 9

ON
OFF
OFF
OFF
OFF
OFF
OFF

U129
pin 9

ON
OFF
OFF
OFF
OFF
OFF
OFF

Gain
(U166)

×100
×10
×10
×10
×1
×1
×1

Gain
(U166)

×100
×10
×10
×10
×1
×1
×1

Figure 4-3 provides a block diagram of the analog circuitry. Table 4-17 shows where the var-

ious switching devices are located in the block diagram.

Table 4-17

Switching device locations

Switching devices Analog circuit section (see Figure 4-3)

Q101, Q102
Q114, Q136, Q109
K101, Q113, Q105, Q104, Q108
Q121
K102, U103, U105, U111
U133, Q120, Q123, Q124, Q125, Q126
K103
U129, U163

SSP (Solid State Protection)
DCV Divider
DCV and Ohms Switching
Sense LO
AC switching and Gain
Ohms I-Source
Current Shunts
A/D Mux and Gain

4-18 Troubleshooting

No comm link error

A “No Comm Link” error indicates that the front panel processor has ceased communication
with the main processor, which is located on the motherboard. This error indicates that there
may be a problem with the cable connection from the front panel display or one of the main
processor ROMs may require reseating in its socket. Check to be sure there is a proper cable
connection from the front panel display. ROMs may be reseated as follows:

1. Turn off the power, and disconnect the line cord and all other test leads and cables from
the instrument.

2. Remove the case cover as outlined in Section 5.

3. Find the two firmware ROMs, U156 and U157, located on the motherboard. These are
the only ICs installed in sockets. (Refer to the component layout drawing at the end of
Section 6 for exact locations.)

4. Carefully push down on each ROM IC to make sure it is properly seated in its socket.

CAUTION Be careful not to push down excessively or you might crack the mother

board.

5. Connect the line cord, and turn on the power. If the problem persists, additional trouble­shooting will be required.

5

Disassembly

5-2 Disassembly

Introduction

This section explains how to handle, clean, and disassemble the Model 2700 Multimeter/

Data Acquisition System. Disassembly drawings are located at the end of this section.

Handling and cleaning

To avoid contaminating PC board traces with body oil or other foreign matter, avoid touch­ing the PC board traces while you are repairing the instrument. Some circuit board areas, espe­cially those under the motherboard shield, have high-impedance devices or sensitive circuitry
where contamination could cause degraded performance.

Handling PC boards

Observe the following precautions when handling PC boards:

• Wear cotton gloves.

• Only handle PC boards by the edges and shields.

• Do not touch any board traces or components not associated with repair.

• Do not touch areas adjacent to electrical contacts.

• Use dry nitrogen gas to clean dust off PC boards.

Solder repairs

Observe the following precautions when soldering a circuit board:

• Use an OA-based (organic activated) flux, and take care not to spread the flux to other
areas of the circuit board.

• Remove the flux from the work area when you have finished the repair by using pure
water with clean, foam-tipped swabs or a clean, soft brush.

• Once you have removed the flux, swab only the repair area with methanol, then blow
dry the board with dry nitrogen gas.

• After cleaning, allow the board to dry in a 50°C, low-humidity environment for several
hours.