Keithley 2701 User guide

Model 2701 Ethernet-Based DMM / Data Acquisition System

A GREATER MEASURE OF CONFIDENCE

Service Manual

WARRANTY

Keithley Instruments, Inc. warrants this product to be free from defects in material and workmanship for a
period of 3 years 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.

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

CHINA: Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: [phone]
FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: [phone] • Fax: [phone]
FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: [phone]
GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: [phone]
GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: [phone]
INDIA: Flat 2B, Willocrissa • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: [phone]
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JAPAN: New Pier Takeshiba North Tower 13F • 11-1, Kaigan 1-chome • Minato-ku, Tokyo 105-0022 • 81-3-5733-7555 • Fax: [phone]
KOREA: 2FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-888 • 82-2-574-7778 • Fax: [phone]
NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: [phone]
SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 679 • Fax: [phone]
SWITZERLAND: Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: [phone]
TAIWAN: 1FL., 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077• Fax: [phone]

28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: [phone]

1-888-KEITHLEY (534-8453) • www.keithley.com

4/02

Model 2701 Ethernet-Based DMM / Data Acquisition System

Service Manual

©2002, Keithley Instruments, Inc.

All rights reserved.
Cleveland, Ohio, U.S.A.
First Printing, June 2002

Document Number: 2701-902-01 Rev. A

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 2701-902-01).................................................................... June 2002

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.

S

afety 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 and follow all installation, operation, and maintenance information carefully before us­ing the product. Refer to the manual for complete product specifications.

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

Responsible body

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

Operators

instrument. They must be protected from electric shock and contact with hazardous live circuits.

Maintenance personnel

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

trained service personnel may perform installation and service procedures.
Keithley products are designed for use with electrical signals that are rated Installation Category I and Installation Category II,

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

Exercise extreme caution when a shock hazard is present. Lethal voltage may be present on cable connector jacks or test fixtures.
The American National Standards Institute (ANSI) states that a shock hazard exists when voltage levels greater than 30V RMS,

42.4V peak, or 60VDC are present.

circuit before measuring.

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

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

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

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

For maximum safety, do not touch the product, test cables, or any other instruments while power is applied to the circuit under
test. ALWAYS remove power from the entire test system and discharge any capacitors before: connecting or disconnecting ca-

is the individual or group responsible for the use and maintenance of equipment, for ensuring that the equip-

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

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

are trained to work on live circuits, and perform safe installations and repairs of products. Only properly

A good safety practice is to expect that hazardous voltage is present in any unknown

no conductive part of the circuit may be exposed.

5/02

bles or jumpers, installing or removing switching cards, or making internal changes, such as installing or removing jumpers.
Do not touch any object that could provide a current path to the common side of the circuit under test or power line (earth) ground. Al-

ways 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 in-

formation, 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 or 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

information very carefully before performing the indicated procedure.
The

CAUTION

ranty.
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 dangers that might result in personal injury or death. Always read the associated

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

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 2701 verification ............................................................. 1-8

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

Verifying AC voltage ......................................................... 1-10

Verifying DC current ......................................................... 1-12

Verifying AC current ......................................................... 1-13

Verifying resistance ........................................................... 1-14

Verifying temperature ....................................................... 1-16

Verifying frequency .......................................................... 1-18

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 ....................................................... 1-28

Verifying frequency .......................................................... 1-31

Verifying ratio and average ............................................... 1-32

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 ........................................................ 2-19

Recommended test equipment .......................................... 2-19

Calibration card preparation .............................................. 2-19

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

Measuring function generator signal amplitude ................ 2-20

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

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

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

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

Calibration card 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 Model 7700 plug-in module amps fuses ................... 3-5

Replacing non-volatile RAM battery ......................................... 3-6

Plug-in module relay closure count ............................................ 3-7

Closure count commands .................................................... 3-7

Reading relay closure count ................................................ 3-7

Resetting relay closure count .............................................. 3-8

Setting count update interval ............................................... 3-8

4Troubleshooting

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

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

Power-on self-tests ...................................................................... 4-3

RAM and EPROM tests ...................................................... 4-3

Flash memory tests .............................................................. 4-3

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

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

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

Principles of operation ................................................................ 4-5

Power supply ....................................................................... 4-5

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

Digital circuitry ................................................................... 4-8

Analog circuitry ................................................................. 4-10

Troubleshooting ....................................................................... 4-13

Display board checks ........................................................ 4-13

Power supply checks ......................................................... 4-13

Digital circuitry checks ..................................................... 4-14

Analog signal switching states .......................................... 4-14

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 ...................................................... 5-5

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-2

Calculating DC characteristics accuracy ........................... A-2

Calculating AC characteristics accuracy ............................ A-2

Calculating dBm characteristics accuracy ......................... A-3

Calculating dB characteristics accuracy ............................ A-4

Additional derating factors ................................................ A-4

Optimizing measurement accuracy ........................................... A-5

DC voltage, DC current, and resistance: ............................ A-5

AC voltage and AC current: ............................................... A-5

Temperature: ...................................................................... A-5

Optimizing measurement speed ................................................ A-5

DC voltage, DC current, and resistance: ............................ A-5

AC voltage and AC current: ............................................... A-5

Temperature: ....................................................................... A-5

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

:DATA? ............................................................................... B-8

DC calibration commands ......................................................... B-9

:STEP1 ............................................................................... B-9

:STEP2 ............................................................................. B-10

:STEP3 ............................................................................. B-10

:STEP4 ............................................................................. B-10

:STEP5 ............................................................................. B-11

:STEP6 ............................................................................. B-11

:STEP7 ............................................................................. B-11

:STEP8 ............................................................................. B-12

:STEP9 ............................................................................. B-12

:STEP10 ........................................................................... B-12

:STEP11 ........................................................................... B-13

:STEP12 ........................................................................... B-13

AC calibration commands ....................................................... B-14

:AC:STEP<n> .................................................................. B-15

Manufacturing calibration commands ..................................... B-16

:AC:STEP<14|15> ............................................................ B-16

:DC:STEP0 ....................................................................... B-16

Model 7700 calibration commands ......................................... B-17

:CODE .............................................................................. B-18

:COUNt? .......................................................................... B-18

:DATE? ............................................................................. B-19

:INIT ................................................................................ B-19

:LOCK .............................................................................. B-20

:LOCK? ............................................................................ B-20

:RCOunt ........................................................................... B-20

:SAVE .............................................................................. B-21

:STEP0 ............................................................................. B-21

Remote error reporting ............................................................ B-22

Error summary ................................................................. B-22

Error queue ....................................................................... B-24

Status byte EAV (Error Available) bit .............................. B-24

Detecting calibration step completion ..................................... B-24

List of Illustrations

1 Performance Verification

Figure 1-1 Connections for Model 2701 DC volts verification ............... 1-8

Figure 1-2 Connections for Model 2701 AC volts verification .............. 1-10

Figure 1-3 Connections for Model 2701 DC current verification .......... 1-12

Figure 1-4 Connections for Model 2701 AC current verification .......... 1-13

Figure 1-5 Connections for Model 2701 resistance verification

(100ΩΩ to 10MΩ ranges) ............................................... 1-14

Figure 1-6 Connections for Model 2701 resistance verification

(100MΩ range) ................................................................ 1-15

Figure 1-7 Connections for Model 2701 frequency verification ............ 1-18

Figure 1-8 Connections for Model 7700 DC volts verification ............. 1-19

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) ................................................................ 1-27

Figure 1-14 Connections for Model 7700 thermocouple temperature

verification ....................................................................... 1-29

Figure 1-15 Connections for Model 7700 frequency verification ............ 1-31

Figure 1-16 Connections for Model 7700 ratio and average verification 1-32

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

4Troubleshooting

Figure 4-1 Power supply block diagram .................................................. 4-5

Figure 4-2 Digital circuitry block diagram .............................................. 4-7

Figure 4-3 Analog circuitry block diagram ........................................... 4-11

Figure 4-4 Ohms open-lead sense detection block diagram .................. 4-12

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

Table 1-4 DCI limits ............................................................................ 1-12

Table 1-5 ACI limits ............................................................................. 1-13

Table 1-6 Limits for resistance verification ......................................... 1-15

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 ................ 1-26

Table 1-14 Model 7700 thermocouple temperature verification

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

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 .......................... 2-18

Table 2-13 Recommended equipment for manufacturing calibration ... 2-19

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

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

reading limits ................................................................... 1-30

3 Routine Maintenance

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

Table 3-2 Closure count commands ....................................................... 3-7

4Troubleshooting

Table 4-1 Flash memory failure modes .................................................. 4-3

Table 4-2 Power supply components ...................................................... 4-6

Table 4-3 Display board checks ........................................................... 4-13

Table 4-4 Power supply checks ............................................................ 4-13

Table 4-5 Digital circuitry checks ........................................................ 4-14

Table 4-6 DCV signal switching .......................................................... 4-14

Table 4-8

Table 4-7 ACV and FREQ signal switching ........................................ 4-15

Table 4-10

Table 4-11 DCA signal switching .......................................................... 4-16

Table 4-9

Table 4-13 DCV signal multiplexing and gain ....................................... 4-17

Table 4-14 ACV and ACA signal multiplexing and gain ....................... 4-17

Table 4-12 ACA signal switching .......................................................... 4-17

Table 4-16
Table 4-17

Table 4-15 DCA signal multiplexing and gain ....................................... 4-18

Table 4-18 Switching device locations ................................................... 4-19

Ω

2 signal switching .............................................................. 4-15

Ω2/Ω

4 reference switching .................................................. 4-16

Ω

4 signal switching .............................................................. 4-16

Ω

2 signal multiplexing and gain .......................................... 4-18

Ω

4 signal multiplexing and gain .......................................... 4-18

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 2701 motherboard parts list ........................................ 6-3

Table 6-2 Model 2701 display board parts list ..................................... 6-11

Table 6-3 Model 2701 backplane board parts list ................................ 6-11

Table 6-4 Model 2701 miscellaneous parts list .................................... 6-12

Table 6-5 Model 7700 parts list ............................................................ 6-13

B Calibration Reference

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

Table B-2 DC calibration commands ..................................................... B-9

Table B-3 AC calibration commands ................................................... B-14

Table B-4 Model 7700 calibration commands ..................................... B-17

Table B-5 Calibration error summary .................................................. B-22

1

Performance Verification

1-2 Performance Verification Model 2701 Service Manual

Introduction

Use the procedures in this section to verify that Model 2701 Ethernet Multimeter/Data
Acquisition System accuracy is within the limits stated in the instrument’s one-year accuracy
specifications. You can perform these verification procedures:

• Upon receiving the instrument, make sure it was not damaged during shipment and the
unit meets factory specifications.

• If the instrument’s accuracy is questionable.

•Following calibration.

WARNING

NOTE

There are two general verification procedures in this section:

•

Model 2701 verification

Model 2701 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 2701 plug-in
modules that have similar functions. For specific information about the individual
modules, refer to the appropriate appendices in the Model 2701 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

Model 2701 Service Manual Performance Verification 1-3

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 2701 to warm up for at least two hours before conducting the verification

procedures.

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 2701 requires a line voltage of 100V/120V/220V/240V ±10% and a line
frequency of 45Hz to 66Hz or 360Hz to 440Hz. 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 Model 2701 Service Manual

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

Stanford Research Systems DS345 Function Generator:

1V RMS 1kHz, ±5ppm

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

20mA ±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

Model 2701 Service Manual Performance Verification 1-5

Verification limits

The verification limits stated in this section have been calculated using only the Model 2701
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 2701 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 2701 one-year accuracy
specification for 10V DC of ± (30ppm of reading + 5ppm of range), the calculated limits are:

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
calibration resistance value. Using Model 2701 one-year 10k
reading + 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

to 10.03106k

Ω

Ω

range accuracy of ± (100ppm of

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 Model 2701 Service Manual

Performing the verification test procedures

Verification test summary

Verification tests can be performed either through the Model 2701 front panel terminals or

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

•

Model 2701 verification

the front panel terminals.

Model 7700 verification

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

Model 2701 tests

Model 2701 verification test procedures include:

• DC volts

•AC volts

• DC current

•AC current

• Resistance

•Temperature

• Frequency

— Use this procedure to test Model 2701 accuracy through

— 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

Model 2701 Service Manual Performance Verification 1-7

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 2701 to be on an incorrect range. For each test signal, you must manu­ally set the correct range for the Model 2701 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.

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 2701 Service Manual

Model 2701 verification

Perform these tests to verify accuracy using the Model 2701 front panel terminals.

Verifying DC voltage

Check DC voltage accuracy by applying accurate voltages from the DC voltage calibrator to
the Model 2701 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 2701 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 2701 DC volts verification

INPUT HI

Model 2701

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

INPUTS

F

FRONT/REAR

CAT I

PEAK

LO

500V

PEAK

R

3A 250V

AMPS

POWER

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

DCI

LIMITS ON/OFFDELAY

CONFIG HALT

STEP SCAN

RECALL

OCOMP

CH AVG

ACI

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

PERIOD SENSOR

FREQ

TEMP

RANGE

CH-OFF CARD

EXIT ENTER

AUTO

RANGE

RS-232ETHERNET

RELFILTER

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

HOLD

LOCAL

EX TRIG

TRIG

STORE

SAVE SETUP

CLOSE

OPEN

INPUT LO

OUTPUT

HI

OUTPUT

LO

Calibrator (Output DC Voltage)

Note: Use shielded, low-thermal cables

for 100mV and 1V ranges.

Model 2701 Service Manual Performance Verification 1-9

2. Select the DC volts function by pressing the

DCV

key and set the Model 2701 to the

100mV range.

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

4. Enable the Model 2701 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

99.9935 to 100.0065mV

0.999963 to 1.000037V

9.99965 to 10.00035V

99.9946 to 100.0054V

999.941 to 1000.059V

1-10 Performance Verification Model 2701 Service Manual

Verifying AC voltage

Check AC voltage accuracy by applying accurate AC voltages at specific frequencies from
the AC voltage calibrator to the Model 2701 inputs and verifying that the displayed readings
fall within specified ranges.

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 2701 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 2701 AC volts verification

Note: Amplifier required only

for 700V, 50kHz output.

INPUT HI

Model 2701

Integra Series

SENSE

INPUT

4 WIRE

Ω

HI

350V

1000V

!

PEAK

INPUTS

F

FRONT/REAR

CAT I

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

POWER

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

DCI

LIMITS ON/OFFDELAY

CONFIG HALT

STEP SCAN

RECALL

OCOMP

CH AVG

ACI

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

PERIOD SENSOR

FREQ

TEMP

RANGE

CH-OFF CARD

EXIT ENTER

AUTO

RANGE

RS-232ETHERNET

RELFILTER

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

HOLD

LOCAL

EX TRIG

TRIG

STORE

SAVE SETUP

CLOSE

OPEN

INPUT LO

×

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

Amplifier (Connect to calibrator)

OUTPUT

HI

Shielded

cable

Calibrator (Output AC Voltage)

OUTPUT

LO

Model 2701 Service Manual Performance Verification 1-11

2. Select the AC volts function by pressing the

ACV

key.

3. Set the Model 2701 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 2701 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

1-12 Performance Verification Model 2701 Service Manual

Verifying DC current

Check DC current accuracy by applying accurate DC currents from the DC current calibra­tor to the AMPS input of the Model 2701 and verifying that the displayed readings fall within
specified limits.

Follow these steps to verify DC current accuracy:

1. Connect the Model 2701 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 2701 DC current verification

POWER

AUTO

SENSE

Ω 4 WIRE

350V
PEAK

INPUTS

F

R

FRONT/REAR

CAT I

AMPS

INPUT LO

INPUT

HI

1000V

!

PEAK

LO

500V
PEAK

3A 250V

AMPS

OUTPUT

HI

OUTPUT

Model 2701

Integra Series

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

DCI

LIMITS ON/OFFDELAY

CONFIG HALT

STEP SCAN

RECALL

OCOMP

CH AVG

ACI

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

PERIOD SENSOR

FREQ

TEMP

RANGE

CH-OFF CARD

RELFILTER

EXIT ENTER

RANGE

RS-232ETHERNET

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

HOLD

LOCAL

EX TRIG

TRIG

STORE

SAVE SETUP

CLOSE

OPEN

LO

2. Select the DC current measurement function by pressing the

Calibrator (Output DC Current)

Note: Be sure calibrator is set for

normal current output.

DCI

key.

3. Set the Model 2701 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**

19.98840 to 20.011160mA

99.8700 to 100.1300mA

0.999120 to 1.000880A

2.99628 to 3.00372A

* 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.

Model 2701 Service Manual Performance Verification 1-13

Verifying AC current

Check AC current accuracy by applying accurate AC voltage current at specific frequencies
from the AC current calibrator to the Model 2701 input, verifying that the displayed readings
fall within specified limits. Follow these steps to verify AC current.

1. Connect the Model 2701 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 2701 AC current verification

POWER

INPUT LO

Model 2701

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

RATIO

CH AVG

MATH

OUTPUT

SHIFT

DCV

LOCAL

EX TRIG

SAVE SETUP

OPEN

ACI

ACV

HOLD

TRIG

CLOSE

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

RECALL

Ω2 Ω4

TYPE

TEST

DIGITS RATE

OCOMP

MONITOR

LSYNC

RELFILTER

PERIOD SENSOR

FREQ

TEMP

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

Integra Series

RANGE

AUTO

RANGE

SENSE

Ω 4 WIRE

350V

PEAK

INPUTS

F

FRONT/REAR

CAT I

AMPS

INPUT

HI

1000V

!

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

OUTPUT

HI

OUTPUT LO

Calibrator (Output AC Current)

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

3. Set the Model 2701 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

2.9817 to 3.0183A

1-14 Performance Verification Model 2701 Service Manual

Verifying resistance

Check resistance by connecting accurate resistance values to the Model 2701 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 2701 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 2701 resistance verification (100Ω to 10MΩ ranges)

POWER

SENSE

HI

INPUT

HI

Model 2701

Integra Series

SENSE

INPUT

Ω 4 WIRE

HI

350V

1000V

!

PEAK

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

DCI

LIMITS ON/OFFDELAY

CONFIG HALT

STEP SCAN

RECALL

OCOMP

CH AVG

ACI

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

PERIOD SENSOR

FREQ

TEMP

RANGE

CH-OFF CARD

EXIT ENTER

AUTO

RANGE

RS-232ETHERNET

RELFILTER

RATIO

MATH

OUTPUT

SHIFT

DCV

ACV

HOLD

LOCAL

EX TRIG

TRIG

STORE

SAVE SETUP

CLOSE

OPEN

INPUTS

F

FRONT/REAR

CAT I

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

OUTPUT

HI

SENSE HI

Resistance Calibrator

OUTPUT

LO

SENSELOINPUT

HI

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 2701 4-wire resistance function by pressing the Ω4 key, then choose
the SLOW integration rate with the RATE key.

4. Set the Model 2701 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.

Model 2701 Service Manual Performance Verification 1-15

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 2701 INPUT and SENSE jacks to the calibrator as shown in

Figure 1-6.

8. Disable external sense on the calibrator.

9. Set the Model 2701 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 2701 resistance verification (100MΩ range)

SENSE

INPUT

HI

LOCAL

POWER

Model 2701

Integra Series

SENSE

Ω 4 WIRE

350V

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

OCOMP

RATIO

CH AVG

MATH

OUTPUT

SHIFT

DCV

EX TRIG

SAVE SETUP

OPEN

ACI

ACV

DCI

HOLD

LIMITS ON/OFFDELAY

TRIG

STORE

RECALL

CONFIG HALT

CLOSE

STEP SCAN

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

RELFILTER

PERIOD SENSOR

FREQ

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

PEAK

RANGE

RANGE

INPUTS

F

AUTO

FRONT/REAR

CAT I

TEMP

HI

INPUT

HI

1000V

!

PEAK

LO

500V
PEAK

R

3A 250V

AMPS

OUTPUT

HI

OUTPUT

LO

SENSELOINPUT

Note: Use shielded, low-thermal cables to

HI

Resistance Calibrator

minimize noise. Disable calibrator
external sense.

Table 1-6

Limits for resistance verification

Nominal

Ω Range

100Ω∗
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

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

** Calculate limits based on actual calibration resistance values and Model 2701 one-year resistance accuracy specifications. See

Verification limits.

resistance

100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ

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

99.9880 to 100.0120Ω

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

1-16 Performance Verification Model 2701 Service Manual

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 2701 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 2701 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.

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

K

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

cedure to set reference junction temperature.

-7.659mV
0mV

42.280mV

-5.730mV
0mV

54.138mV

-190.2° to -189.8°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