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: 02/363 00 64

CHINA: Yuan Chen Xin Building, Room 705 • 12 Yumin Road, Dewai, Madian • Beijing 100029 • 8610-6202-2886 • Fax: 8610-6202-2892 FINLAND: Tietäjäntie 2 • 02130 Espoo • Phone: 09-54 75 08 10 • Fax: 09-25 10 51 00 FRANCE: 3, allée des Garays • 91127 Palaiseau Cédex • 01-64 53 20 20 • Fax: 01-60 11 77 26 GERMANY: Landsberger Strasse 65 • 82110 Germering • 089/84 93 07-40 • Fax: 089/84 93 07-34 GREAT BRITAIN: Unit 2 Commerce Park, Brunel Road • Theale • Berkshire RG7 4AB • 0118 929 7500 • Fax: 0118 929 7519 INDIA: Flat 2B, Willocrissa • 14, Rest House Crescent • Bangalore 560 001 • 91-80-509-1320/21 • Fax: 91-80-509-1322 ITALY: Viale San Gimignano, 38 • 20146 Milano • 02-48 39 16 01 • Fax: 02-48 30 22 74 JAPAN: New Pier Takeshiba North Tower 13F • 11-1, Kaigan 1-chome • Minato-ku, Tokyo 105-0022 • 81-3-5733-7555 • Fax: 81-3-5733-7556 KOREA: 2FL., URI Building • 2-14 Yangjae-Dong • Seocho-Gu, Seoul 137-888 • 82-2-574-7778 • Fax: 82-2-574-7838 NETHERLANDS: Postbus 559 • 4200 AN Gorinchem • 0183-635333 • Fax: 0183-630821 SWEDEN: c/o Regus Business Centre • Frosundaviks Allé 15, 4tr • 169 70 Solna • 08-509 04 679 • Fax: 08-655 26 10 SWITZERLAND: Kriesbachstrasse 4 • 8600 Dübendorf • 01-821 94 44 • Fax: 01-820 30 81 TAIWAN: 1FL., 85 Po Ai Street • Hsinchu, Taiwan, R.O.C. • 886-3-572-9077• Fax: 886-3-572-9031

28775 Aurora Road • Cleveland, Ohio 44139 • 440-248-0400 • Fax: 440-248-6168

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

4/02

Model 2701 Ethernet-Based DMM / Data Acquisition System

Service Manual

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.

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

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%

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

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

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

350V

1000V

PEAK

INPUTS

FRONT/REAR

CAT I

PEAK

500V

PEAK

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

OPEN

INPUT LO

OUTPUT

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

350V

1000V

PEAK

INPUTS

FRONT/REAR

CAT I

PEAK

500V PEAK

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

OPEN

INPUT LO

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

Amplifier (Connect to calibrator)

OUTPUT

Shielded

cable

Calibrator (Output AC Voltage)

OUTPUT

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

FRONT/REAR

CAT I

AMPS

INPUT LO

INPUT

1000V

PEAK

500V PEAK

3A 250V

AMPS

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

OPEN

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

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

FRONT/REAR

CAT I

AMPS

INPUT

1000V

PEAK

500V PEAK

3A 250V

AMPS

OUTPUT

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

INPUT

Model 2701

Integra Series

SENSE

INPUT

Ω 4 WIRE

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

OPEN

INPUTS

FRONT/REAR

CAT I

PEAK

500V PEAK

3A 250V

AMPS

OUTPUT

SENSE HI

Resistance Calibrator

OUTPUT

SENSELOINPUT

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

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

STEP SCAN

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

RELFILTER

PERIOD SENSOR

FREQ

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

PEAK

RANGE

INPUTS

AUTO

FRONT/REAR

CAT I

TEMP

INPUT

1000V

PEAK

500V PEAK

3A 250V

AMPS

OUTPUT

SENSELOINPUT

Note: Use shielded, low-thermal cables to

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)

*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

Model 2701 Service Manual Performance Verification 1-17

RTD temperature

1. Connect the precision decade resistance box (listed in Table 1-1) to the Model 2701 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 2701 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.

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

*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

1-18 Performance Verification Model 2701 Service Manual

Verifying frequency

Follow the steps below to verify the Model 2701 frequency function:

1. Connect the function generator to the Model 2701 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 2701 frequency function by pressing the FREQ key.

4. Verify that the Model 2701 frequency reading is between 999.9Hz and 1.0001kHz.

Figure 1-7

Connections for Model 2701 frequency veriﬁcation

BNC-to-Dual

INPUT

3A 250V

AMPS

Banana Jack

1000V PEAK

500V

PEAK

Adapter

50Ω

Coax Cable

Function Generator

Function

Output

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

Model 2701

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

RATIO

CH AVG

OUTPUT

ACI

HOLD

TRIG

ACV

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

RECALL

Ω2 Ω4

TYPE

TEST

DIGITS RATE

OCOMP

MONITOR

RELFILTER

LSYNC

PERIOD SENSOR

FREQ

TEMP

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

Integra Series

RANGE

AUTO

RANGE

SENSE

Ω 4 WIRE

350V PEAK

INPUTS

FRONT/REAR

CAT I

INPUT

HI AND LO

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 pr ocedur es can be used for other plug-in modules that have similar capabilities. Refer to the Model 2701 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

terminals or between any adjacent channels.

Model 2701 Service Manual Performance Verification 1-19

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

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

HLHL

CH5

CH4

CH3

CH1 CH2

Model 7700

2. Install the Model 7700 in Slot 1 of the Model 2701, then turn on the power and allow

3. Select the DC volts function by pressing the DCV key and set the Model 2701 to the

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

5. Enable the Model 2701 REL mode. Leave REL enabled for the remainder of the DC

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

7. Press the OPEN key to open Channel 1.

Calibrator (Output DC Voltage)

CH6

CH7 CH8 CH9 CH10

HLHLHLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Output HI

Output

Note: Use shielded, low-thermal cables

for 100mV and 1V ranges.

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

100mV range. Close Channel 1 by pressing the CLOSE key and then keying in 101.

volts veriﬁcation tests.

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

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

100.0000mV

1.000000V

10.00000V

100.0000V

300.000V

*Source positive and negative values for each range.

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 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 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

terminals or between adjacent channels, or 8 × 10

instrument 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

INPUT SENSE

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

CH5

CH6

CH4

CH3

CH1 CH2

Model 7700

Output HI

Shielded

Cable

V•Hz input, because

Amplifier (Connect to calibrator)

Calibrator (Output AC Voltage)

Output

Model 2701 Service Manual Performance Verification 1-21

2. Install the Model 7700 in Slot 1 of the Model 2701, 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 2701 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 2701 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 Model 2701 Service Manual

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

AMPS

CH4

CH5

CH6

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Output HI

Output

Calibrator (Output DC Current)

Note: Be sure calibrator is set for

normal current output.

Model 2701 Service Manual Performance Verification 1-23

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

4. Set the Model 2701 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**

19.98840 to 20.01160mA

99.8700 to 100.1300mA

0.999120 to 1.000880A

2.99628 to 3.00372A

1-24 Performance Verification Model 2701 Service Manual

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

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

CH21

Model 7700

CH1 CH2 HLHL

HLHL

HLHLHLHLHLHL

CH7 CH8 CH9 CH10

HLHLHLHL

CH17 CH18 CH19 CH20

CH5

CH6

CH4

CH3

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

4. Set the Model 2701 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

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

Model 2701 Service Manual Performance Verification 1-25

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

Resistance Calibrator

INPUT SENSE HLHL

Model 7700

CH4

CH3

CH1 CH2

HLHL

CH5

HLHL

CH6

CH7 CH8 CH9 CH10

HLHLHLHL

INPUT

(V, 2 WIRE)

HLHL CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

CH11

HLHLHLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

SENSE

(OHMS, 4 WIRE)

Output

Sense LO

Note: Use shielded, low-thermal cables

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

1-26 Performance Verification Model 2701 Service Manual

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

4. Select the Model 2701 4-wire resistance function by pressing the Ω4 key. Close Channel 1 by pressing the CLOSE key and keying in 101.

5. Set the Model 2701 for the 100Ω range and make sure the FILTER is on. Enable OCOMP (offset-compensated ohms) for the 100Ω range test. (Press SHIFT then OCOMP.)

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

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.

Table 1-13

Limits for plug-in module resistance veriﬁcation

Nominal

Ω Range

100Ω∗ 1kΩ 10kΩ 100kΩ 1MΩ 10MΩ 100MΩ

* Enable OCOMP for 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

9.99370 to 10.00630MΩ

99.5770 to 100.4230MΩ

Model 2701 Service Manual Performance Verification 1-27

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 2701 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

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

Note: Use shielded cables to minimize

noise. Disable calibrator external sense mode.

1-28 Performance Verification Model 2701 Service Manual

Verifying temperature

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.

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 2701 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.

Model 2701 Service Manual Performance Verification 1-29

Figure 1-14

Connections for Model 7700 thermocouple temperature veriﬁcation

CH1

INPUT SENSE HLHL

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

HLHL

AMPS

HLHL

CH4

CH3

CH1 CH2

Model 7700

CH5

CH6

HLHL

CH7 CH8 CH9 CH10 HLHLHLHL

HLHLHLHL CH17 CH18 CH19 CH20

HLHLHLHLHLHL

Make HI and LO

Connections

in Ice Bath

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Twisted

Thermocouple Wire

Output

Ice Bath

Calibrator (Output DC Voltage)

Low Thermal

Copper Connection

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.

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)

-7.659mV 0mV

42.280mV

-5.730mV 0mV

54.138mV

*Voltages shown are based on ITS-90 standard.

-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

1-30 Performance Verification Model 2701 Service Manual

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.)

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 2701 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:

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

Model 2701 Service Manual Performance Verification 1-31

Verifying frequency

Follow the steps below to verify the Model 2701 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 2701, 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 2701 frequency function by pressing the FREQ key. Close Channel 1 by pressing the CLOSE key and keying in 101.

5. Verify that the Model 2701 frequency reading is between 0.9999kHz and 1.0001kHz.

Figure 1-15

Connections for Model 7700 frequency veriﬁcation

CH1

INPUT SENSE

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

HLHL

HLHLHLHLHLHL

CH5

CH4

CH3

CH1 CH2

Model 7700

CH6

CH7 CH8 CH9 CH10 HLHLHLHL

HLHLHLHL

CH17 CH18 CH19 CH20

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Function Generator

50Ω

Coax Cable

Function

Output

1-32 Performance Verification Model 2701 Service Manual

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

terminals may cause instrument damage.

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

3. Select the Model 2701 DCV function and the 1V range. Close Channel 1 by pressing the CLOSE key and keying in 101.

4. Select the Model 2701 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

CH1 CH2

INPUT SENSE

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

HLHL

AMPS

HLHL

CH11

CH5

CH6

CH4

CH3

HLHL

CH7 CH8 CH9 CH10

HLHLHLHL

CH17 CH18 CH19 CH20

HLHLHLHLHLHL

Model 7700

INPUT

(V, 2 WIRE)

SENSE

(OHMS, 4 WIRE)

Output HI

Output

DC Voltage Calibrator

Note: Use shielded cables

to minimize noise.

Calibration

2-2 Calibration Model 2701 Service Manual

Introduction

Use the procedures in this section to calibrate the Model 2701. 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 Ethernet port 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 2701 Ethernet 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

Model 2701 Service Manual Calibration 2-3

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 2701 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.

• 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 Model 2701 Service Manual

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 2701 then prompts you to enter a code: CODE? 000000 (The factory default code is 002701.) 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 2701 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 Ethernet port 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 'KI002701'.

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

with the present code and then with the new code.

Model 2701 Service Manual Calibration 2-5

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 as that equipment has speciﬁcations at least as good as those listed in Table 2-1.

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 Model 2701 Service Manual

Aborting 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 calibration

process.

NOTE The Model 2701 will not respond to any remote programming commands while the

ABORT CAL? message is displayed.

Front panel calibration

Perform 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 2701 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 and saving calibration

Preparing the Model 2701 for calibration

1. Turn on the Model 2701 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 002701.) 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 CAL: RUN prompt. Use the up and down range keys to scroll through the options; select your choice by pressing ENTER.

Model 2701 Service Manual Calibration 2-7

Table 2-2

Comprehensive calibration procedures

Procedure Menu choice Procedures

Full calibration DCV, DCI, and ohms ACV and ACI

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 2701 prompt for a front panel short, perform 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.

Figure 2-1

Low thermal short connections

SENSE

INPUTS

INPUT

Model 8610

1000V

PEAK

Low-thermal

500V

PEAK

3A 250V

AMPS

CAT I

short

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

Model 2701

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

RATIO

CH AVG

OUTPUT

ACI

HOLD

TRIG

ACV

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

RECALL

Ω2 Ω4

MONITOR

TYPE

TEST

DIGITS RATE

OCOMP

RELFILTER

LSYNC

PERIOD SENSOR

FREQ

TEMP

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

Integra Series

RANGE

AUTO

RANGE

S-

S+

PEAK

350V

Ω 4 WIRE

FRONT/REAR

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. 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.

2-8 Calibration Model 2701 Service Manual

DC voltage 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 2701 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

INPUT

Model 2701

Integra Series

SENSE

INPUT

Ω 4 WIRE

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

OPEN

INPUTS

FRONT/REAR

CAT I

PEAK

500V PEAK

3A 250V

AMPS

SENSE HI

DC Voltage and Resistance Calibrator

OUTPUT

SENSE

INPUT

Note: Use shielded, low-thermal cables to

SENSE LO

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.

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 2701 ﬁnishes each step. (The unit will display the CALIBRATING message while calibrating.)

Model 2701 Service Manual Calibration 2-9

NOTE If your calibr ator cannot output the values r ecommended in Table 2-3, use the left and

right arrow ke ys and the up and down r ange ke ys to set the Model 2701 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 2701 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 2701 left and right arrow keys and the range keys to adjust the Model 2701 display to agree with the actual calibrator resistance.)

• Press the ENTER key to calibrate each point.

•Wait for the Model 2701 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 2701 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 Model 2701 Service Manual

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 2701 as shown in Figure 2-3.

Figure 2-3

Connections for DC and AC amps calibration

POWER

DC and AC Current Calibrator

Note: Be sure calibrator is set for

normal current output.

AUTO

SENSE

Ω 4 WIRE

350V

PEAK

INPUTS

FRONT/REAR

CAT I

AMPS

INPUT LO

INPUT

1000V

PEAK

500V PEAK

3A 250V

AMPS

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

OPEN

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 2701 display indicates the correct calibration current.

• Press ENTER to complete each step.

• Allow the Model 2701 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

Model 2701 Service Manual Calibration 2-11

AC voltage calibration

Follow these steps for AC voltage calibration:

1. Connect the calibrator to the Model 2701 INPUT HI and LO terminals as shown in

Figure 2-4.

Figure 2-4

Connections for AC volts calibration

LOCAL

POWER

INPUT HI

AC Voltage Calibrator

Model 2701

Integra Series

SENSE

INPUT

Ω 4 WIRE

350V

1000V

PEAK

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

STEP SCAN

Ω2 Ω4

TYPE

TEST

DIGITS RATE

MONITOR

LSYNC

RELFILTER

PERIOD SENSOR

FREQ

TEMP

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

RANGE

AUTO

INPUTS

FRONT/REAR

CAT I

PEAK

500V PEAK

3A 250V

AMPS

INPUT LO

OUTPUT

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 2701 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 Model 2701 Service Manual

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 2701 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, 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 2701 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.

Model 2701 Service Manual Calibration 2-13

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 2701 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 via remote. (See

“Detecting calibration step completion” in Appendix B.)

The procedures for calibrating the Model 2701 via remote include:

• Preparing the Model 2701 for calibration

• Short and open calibration

• DC voltage calibration

• Resistance calibration

• DC current calibration

•AC voltage calibration

•AC current calibration

• Programming calibration dates

•Saving calibration constants

• Locking out calibration

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

or AC-only calibr ation. Be sur e to include a space char acter between each command and parameter.

Preparing the Model 2701 for calibration

1. Connect the Model 2701 to the Ethernet 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 2701 and allow it to warm up for at least two hours before performing calibration.

3. Unlock the calibration function by sending this command: :CAL:PROT:CODE 'KI002701' (The above command shows the default code, KI002701. Substitute the correct code if

changed.)

4. Send the following command to initiate calibration: :CAL:PROT:INIT

2-14 Calibration Model 2701 Service Manual

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 2701 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 voltage calibration

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

1. Connect the calibrator to the Model 2701 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-

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 2701 completes each step before continuing.

Model 2701 Service Manual Calibration 2-15

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 2701 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 Model 2701 Service Manual

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 2701 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 2701 completes each step before continuing.

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

dates” on page 2-18

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

Model 2701 Service Manual Calibration 2-17

AC voltage calibration

Follow these steps for AC voltage calibration:

1. Connect the calibrator to the Model 2701 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, make sure the unit is in operate. (You must use the stated voltage and frequency.)

• Send the indicated programming command.

•Wait until the Model 2701 completes each step before continuing.

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

2-18 Calibration Model 2701 Service Manual

AC current calibration

Follow these steps for AC current calibration:

1. Connect the calibrator to the AMPS and INPUT LO terminals of the Model 2701 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, make sure the unit is in operate. (You must use the stated current and frequency.)

• Send the indicated programming command.

•Wait until the Model 2701 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

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

Model 2701 Service Manual Calibration 2-19

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 compr ehensive 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 System

Calibration card preparation

Before performing manufacturing calibration, short the HI, LO, SHI, and SLO terminals of

TE100 on the Model 7797 Calibration System card together using the supplied jumpers. (See the Model 7797 documentation.) These connections will form a low-thermal short necessary for the manufacturing calibration procedure. The Model 7797 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.

2-20 Calibration Model 2701 Service Manual

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, 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.

Front panel manufacturing calibration

1. Install the shorted Model 7797 calibration board (see “Calibration card 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 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:

002701).

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 2701 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 Jack

Adapter

1000V PEAK

500V PEAK

50Ω

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

Model 2701

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

RATIO

CH AVG

OUTPUT

ACI

HOLD

TRIG

ACV

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

RECALL

Ω2 Ω4

TYPE

TEST

DIGITS RATE

OCOMP

MONITOR

RELFILTER

LSYNC

PERIOD SENSOR

FREQ

TEMP

CH-OFF CARD

RS-232ETHERNET

EXIT ENTER

Integra Series

RANGE

AUTO

RANGE

350V PEAK

SENSE

Ω 4 WIRE

INPUTS

FRONT/REAR

CAT I

INPUT

3A 250V

AMPS

Coax

Cable

INPUT

HI AND LO

Function

Output

Function Generator

Note: Output voltage must be

accurately measured. (See text.)

Model 2701 Service Manual Calibration 2-21

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

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

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

:CAL:PROT:CODE 'KI002701'

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” on page 2-5.)

7. Connect the function generator to the Model 2701 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 command:

: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

2-22 Calibration Model 2701 Service Manual

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 2701 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 Model 7797 Calibration System

Calibration card connections

The Model 7700 being calibrated should be connected to the Model 7797 Calibration System card and the card should then be installed in scanner Slot #1. (See the Model 7797 documentation.) Note that the module being calibrated will be external to the Model 2701 to avoid card heating during calibration.

Model 7700 calibration

NOTE Before calibrating the Model 7700, make sure that power has been remo ved fr om 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 2701 to warm up for at least two hours.

Front panel Model 7700 calibration

1. Connect the Model 7700 to the Model 7797 Calibration System card (see “Calibration

card 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 and hold the Model 2701 OPEN key while turning on the power.

Model 2701 Service Manual 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:

002701).

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 Model 7797 Calibration System card (see “Calibration

card connections” on page 2-22).

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 and hold the Model 2701 OPEN key while turning on the power.

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

:CAL:PROT:CODE 'KI002701'

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

Routine Maintenance

3-2 Routine Maintenance Model 2701 Service Manual

Introduction

The information in this section deals with routine type maintenance and includes procedures for setting the line voltage, replacing the Model 2701 line and front terminal AMPS fuses, and replacing the amps fuses for the Model 7700 plug-in module. Replacement of the Model 2701 non-volatile RAM battery and module relay closure count 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 2701 on the wrong line voltage may result in

instrument damage.

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

Model 2701 Service Manual Routine Maintenance 3-3

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.

Figure 3-1

Power module

Model 2701

DIGITAL I/O (EXT. TRIG.)

10bT 100bT

TRIG. LINK

KEITHLEY

SLOT COVER

ETHERNET

10/100 BaseT

CAT I

MADE IN

U.S.A.

RS232

SLT

Line Voltage Selector

Fuse

220

240

120

100

Spring

Window

Fuse Holder Assembly

Table 3-1

Power line fuse

Line Voltage Rating Keithley Part No.

100/120V 0.630A, 250V, 5 × 20 mm, slow-blow FU-106-.630 200/240V 0.315A, 250V, 5 × 20 mm, slow-blow FU-106-.315

3-4 Routine Maintenance Model 2701 Service Manual

Replacing the front terminal AMPS fuse

The front terminal AMPS fuse protects the Model 2701 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.

Figure 3-2

Front terminal AMPS fuse

Model 2701

Model 2701 Ethernet Multimeter / Data Acquisition System

CONT

RATIO

SHIFT

LOCAL

POWER

MATH

DCV

EX TRIG

SAVE SETUP

OPEN

OUTPUT

ACV

HOLD

TRIG

DCI

LIMITS ON/OFFDELAY

STORE

CONFIG HALT

STEP SCAN

CH AVG

RECALL

ACI

DIGITS RATE

Ω2 Ω4

TYPE

TEST

OCOMP

MONITOR

RELFILTER

LSYNC

Integra Series

PERIOD SENSOR

FREQ

TEMP

CARD

RS-232ETHERNET

EXIT ENTER

RANGE

AUTO

RANGE

CH-OFF

Counterclockwise

SENSE

Ω 4 WIRE

350V PEAK

INPUTS

FRONT/REAR

CAT I

Rotate

INPUT

1000V

PEAK

500V

PEAK

3A 250V

AMPS

Model 2701 Service Manual Routine Maintenance 3-5

Replacing Model 7700 plug-in module amps fuses

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.

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

Model 7700

CH6

CH5

CH4

CH3

CH2

CH1

SENSE

INPUT

HLHL

CH7 CH8 CH9 CH10

HLHLHLHL

INPUT

(V, 2 WIRE)

HLHL

CH21 CH22 CH11 CH12 CH13 CH14 CH15 CH16

AMPS

CH22 Fuse CH21 Fuse

5. De-solder the blown CH21 or CH22 fuse as required, taking care not to damage the cir-

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

SENSE

HLHLHLHL CH17 CH18 CH19 CH20

HLHLHLHLHLHL

(OHMS, 4 WIRE)

cuit board or spread solder ﬂux around the board.

damage may occur.

to damage the circuit board or spread solder ﬂux around the board.

3-6 Routine Maintenance Model 2701 Service Manual

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 non-volatile RAM battery

The Model 2701 has a rechargeable lithium ion 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 There is a danger of explosion if the battery is incorrectly replaced.

Replace only with the part designated by the corresponding Keithley part number. Dispose of used batteries according to the manufacturer’s instructions.

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 2701 before removing the top cover.

WARNING The precautions below must be followed to avoid personal injury.

• Wear safety glasses or goggles when working with lithium ion

batteries.

• Do not short the battery terminals together.

• Keep lithium ion batteries away from all liquids.

• Observe proper polarity when installing the battery.

• Do not incinerate or otherwise expose the battery to excessive heat

(>60°C).

• Bulk quantities of lithium ion batteries should be disposed of as hazardous waste.

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 2701 top cover and motherboard using the disassembly procedures in Section 5.

3. Remove the battery from its holder on the bottom of the case near the front panel.

4. Install a new battery, Keithley part number BA-52.

5. Re-install the motherboard and top cover by following the disassembly procedures in

Section 5 in reverse order. Be sure to plug in all cables including the cable that connects

the battery to the motherboard at J900.

Model 2701 Service Manual Routine Maintenance 3-7

Plug-in module relay closure count

The Model 2701 keeps an internal count of the number of times each module relay has been closed. This count will help you determine if and when any relays require replacement (see module contact life speciﬁcations). The count can be read or reset only via remote as outlined below.

Closure count commands

Table 3-2 summarizes closure count commands.

Table 3-2

Closure count commands

Command Description

:ROUTe

:CLOSe

:COUNt? (@clist)

:INTerval < NRf> :INTerval?

:RCOunt (@clist)

* Unit must be in manufacturing calibration mode. See text below.

Route subsystem.

Path to CLOSe commands.

Query count for channels in clist (channel list).

Set count update interval in minutes (1 to 1440). Query count update interval.

Reset count for channels in clist.*

Reading relay closure count

To determine the closure count of speciﬁc channels, send this query via remote:

:ROUTe:CLOSe:COUNt? (@clist)

Here, clist is the summary of channels. For example, to determine the closure count of channels 1 and 4 of a module in slot 1, the following query would be sent:

:ROUT:CLOS:COUN? (@101,104)

The following query would determine the closure count of slot 1 module channels 1 through 10:

:ROUT:CLOS:COUN? (@101:110)

3-8 Routine Maintenance Model 2701 Service Manual

Resetting relay closure count

NOTE The Model 2701 must be in the manufacturing calibration mode to reset the closure

count. To do so, pr ess and hold the OPEN key while turning on the power, then send the :CAL:PROT:CODE “code” to unlock calibration (default code: KI002701). After resetting relay counts, send :CAL:PROT:LOCK to lock out calibration.

To reset the relay closure count of speciﬁc channels to 0, send this command via remote:

:ROUTe:CLOSe:RCOunt (@clist)

Again clist is the summary of channels to be reset. For example, the following command

resets channels 2 and 7 of a module in slot 1 to 0:

:ROUT:CLOS:RCO (@102,107)

The following command resets the count of slot 1 module channels 1 through 10:

:ROUT:CLOS:RCO (@101:110)

Setting count update interval

Relay closure counts are updated in temporary RAM every time a channel is closed regardless of how it was closed: by a SCPI command, front panel control, or during a scan. These counts are permanently written to the EEPROM on the card only at a user-settable time interval (which has a factory default of 15 minutes) or whenever the counts are queried. Valid intervals (set in integer number of minutes) are between 1 and 1440 minutes (24 hrs). Relay closures are counted only when a relay cycles from open to closed state. If you send multiple close commands to the same channel without sending an open command, only the ﬁrst closure will be counted.

The lower the interval, the less chance there is of losing relay counts due to power failures. However, writing to the EEPROM more often may reduce scanning throughput. The higher the interval, the less scanning throughput is reduced, but more relay counts may be lost in the event of a power failure.

To set the count update interval, send this command:

:ROUTe:CLOSe:COUNt:INTerval <interval>

For example, to set the interval to 30 minutes, send this command:

:ROUT:CLOS:COUN:INT 30

Troubleshooting

4-2 Troubleshooting Model 2701 Service Manual

Introduction

This section of the manual will assist you in troubleshooting and repairing the Model 2701. 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 2701, be sure to read the following considerations.

CAUTION The PC boards are built using surface mount techniques and require

specialized 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 2701 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 2701. 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 2701 must be recalibrated. See Section 2 for details on calibrating the unit.

Model 2701 Service Manual Troubleshooting 4-3

Power-on self-tests

RAM and EPROM tests

During the power-on sequence, the Model 2701 will perform a checksum test on its EPROM

and test its RAM. If the RAM tests fails, the instrument will lock up.

Flash memory tests

After the RAM and EPROM tests, the instrument will perform a checksum test on ﬂash memory. If a failure occurs, the unit will perform the comprehensive tests summarized in

Table 4-1. If a failure occurs, an error message will be displayed, and the unit will automati-

cally enter the ﬁrmware upgrade mode (as indicated by “FW UPGRADE” message). Depending on the failure mode, ﬁrmware upgrades can be performed through the port(s) listed in the table. You can also force the unit into the ﬁrmware upgrade mode by holding in the STEP key during power-up.

Table 4-1

Flash memory failure modes

Flash memory code sections

FPGA LOADING FPGA

Ethernet LOAD ETHRNET

Main code LOADING MAIN

1. Code sections tested in sequence shown.

2. Error message displayed only on failure of speciﬁc test.

3. Firmware upgrade can be performed only through indicated port(s) depending on failure mode.

Status and error messages Firmware upgrade port

RS-232

RS-232 or Ethernet

FPGA CHKSUM FPGA TIMEOUT FPGA COMMERR

ETHER CHKSUM ETHR TIMEOUT

MAIN CHKSUM

4-4 Troubleshooting Model 2701 Service Manual

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” on page 4-13 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

The display test allows you to verify that each segment and annunciator in the vacuum

ﬂuorescent 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.

Model 2701 Service Manual Troubleshooting 4-5

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 Figure 4-4 — Ohms open-lead sense detection 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

C66, C205, C214, U18

U19, U25

CR104, C156

C274, C274

C281, U144

CR116, CR117

C104, U101

CR102

C131, C148

U119, U125

CR103

C146 U124

+1.8VD +2.5VD +3.3VD D Common

+5VD

D Common

+37V

D Common

+18V +15V

A Common

-15V

-18V

+5V

A Common

4-6 Troubleshooting Model 2701 Service Manual

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, then routed to the display board.

Each DC supply uses a rectiﬁer and a capacitive ﬁlter, and many supplies use an IC regulator. Table 4-2 summarizes rectiﬁer, ﬁlter, and regulator circuits for the various DC supplies.

Table 4-2

Power supply components

Supply Rectiﬁer Filter Regulator

+5VD +3.3VD +2.5VD +1.8VD +37V +15V

-15V +5V, +5VRL, +5V2 +18V

-18V

Display board

Display board components are shown in the digital circuitry block diagram in Figure 4-2.

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.

CR104

CR115, CR117 CR102 CR102 CR103 CR102 CR102

C156, C273, C274, C281 C66 C205 C214 C104 C148 C131 C146 C148 C131

U144 U18 U25 U19 U101 U125 U119 U124

Model 2701 Service Manual Troubleshooting 4-7

Figure 4-2

Digital circuitry block diagram

Analog

Circuitry

(See Figure 4-3)

U13 U21 U22

XADTX

XADCLK

XADTS

XADRX

Slot Control

P T

U150 U155 U175

Real Time

Clock

ADTX

ADCLK

ADTS

ADRXB

Flash

Memory

Main Processor

MCF5407

Li Ion Battery

SDRAM

Display Board

Controller

50 MHz

XTAL

RS-232

U15

U401

Battery

Control/

Charger

U4, U16

Keypad

Display

DS401

RS-232

Port

SDRAM

U11

FPGA

Ethernet Processor

NET + ARM

U10

OUT

Digital I/O

U23, U24

Trigger Link

U14, U20

Ethernet

Interface

U12

Digital I/O

Port

Trigger

Link

Connector

10/100 BaseT

Ethernet Port

4-8 Troubleshooting Model 2701 Service Manual

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

Refer to Figure 4-2 for the following discussion on digital circuitry.

Main microprocessor

U1 is an MCF5407 microprocessor that oversees all operating aspects of the instrument except the Ethernet interface (see below). The MPU has a 32-bit data bus and provides a 24-bit address bus. It also has integrated peripheral support such as 16-bit I/O, an integral DRAM controller with SDRAM support, and UARTs, one of which is used for the RS-232 interface.

The MPU clock frequency of 50MHz is controlled by crystal Y1. MPU RESET is performed momentarily on power-up.

Memory circuits

U6 is the ﬂash memory that stores the ﬁrmware code for instrument operation and SDRAM U3 provides temporary storage for the MPU. A battery watchdog control automatically senses when the +5VD supply is being powered down and then switches to the lithium ion battery for power. Battery charge is maintained by U4 and associate components.

Real time clock

U7 is the real time clock. The clock runs from main power and switches to two 0.33F capacitors (C43, C44) on power down and can hold the time for up to six months.

Model 2701 Service Manual Troubleshooting 4-9

RS-232 interface

Serial data transmission and reception is performed by the TXD and RXD lines of the MPU.

U15 provides the necessary voltage level conversion for the RS-232 interface port.

Trigger circuits

Buffering for Trigger Link input and output is performed by U14 and U20. Trigger input and

output is controlled by FPGA U9 under MPU supervision.

Digital I/O

U23 and U24 make up the digital input/output. Digital I/O is controlled by the FPGA U9

under MPU supervision.

Module slot control

U13 and U21 make up the control circuitry that allows communication of relay data to

Slot 1 or Slot 2.

Ethernet interface

U10 is a NET+ARM 32-bit RISC processor that supervises Ethernet port operation. This IC includes an integrated 10/100BaseT MAC as well as numerous other features such as two serial ports, DMA controller, and general-purpose I/O lines. U1 is the ARM processor memory IC, while U12 provides Ethernet port I/O buffering and drive capabilities.

4-10 Troubleshooting Model 2701 Service Manual

Analog circuitry

Refer to Figure 4-3 for the following discussion on analog circuitry.

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) to the DCV switching circuit.

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.

Model 2701 Service Manual Troubleshooting 4-11

Figure 4-3

Analog circuitry block diagram

Front Terminals

S101

Scanner Outputs

Front Terminals

S101

Scanner Outputs

Front Terminals

S101

Scanner Outputs

Front Terminals

S101

Scanner Outputs

AMPS

INPUT

R117, Q109, Q114, Q136

SENSE

Scanner Outputs

Scanner

Inputs

K103, R158, R205, R338

Q101, Q102

DCV

Divider

R120, R121, R124,

R125, Q107, Q148,

VR119, VR120

R132, R139, R148,

R163, Q122, Q135,

VR119, VR120

Current

Shunts

K102, U102, U103, U105,

U112, U118, U111, U110

K101

SSP*

DCV/100

Q124, Q125, Q126,

Protection

Slot 1

DCA

ACA

AC Switching

Gain

ACV,

FREQ

DCV

OHMS

Q120, CR114

Ohms I-Source

Q119, Q123,

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

* Solid State Protection

ADC

U165

Digital

Circuitry

(See

Figure 4-2)

Scanner

Inputs

Slot 2

4-12 Troubleshooting Model 2701 Service Manual

Ohms open-lead sense detection

There are two types of open sense lead detect (Figure 4-4). The ﬁrst is for the INPUT HI and INPUT LO leads. For these leads, the open sense detection is implemented in hardware. A comparator circuit monitors the voltage at the INPUT HI lead output and will trip the OVLD detect circuit when the voltage level exceeds an appropriate value for the particular range. This circuit operates because the INPUT HI lead output is connected to a current source. If the lead is disconnected, it will quickly charge the output to the current source maximum voltage level. This level depends on the range and is documented in the speciﬁcations in Appendix A. When the open sense lead is detected, the front panel will display OVRFLW.

The second type of open sense lead detection is implemented in software. This function works for the SENSE HI and SENSE LO leads. The SENSE HI and SENSE LO leads will drift negative when disconnected due to small leakage currents. These leads, when operating properly, will always have a positive voltage on them; and when disconnected, they will drift to negative voltages. The open lead sense software monitors the voltage at these inputs and will trip the open sense detect when the inputs drift to -15mV. When the open sense condition is detected, the front panel will display OVRFLW.

Figure 4-4

Ohms open-lead sense detection block diagram

SENSE HI

Software Detect

INPUT HI

Hardware Detect

DUT

INPUT LO

SENSE LO

Current

Source

Analog Common

Software Detect

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.

Model 2701 Service Manual Troubleshooting 4-13

Troubleshooting

Troubleshooting information for the various circuits is summarized below. See “Principles

of operation” on page 4-5 for circuit theory.

Display board checks

If the front panel DISP tests show a failure, troubleshoot the display board using Table 4-3.

Table 4-3

Display board checks

Step Item/component Required condition Remarks

Front panel DISP test

P1005, pin 5

P1005, pin 9

U401, pin 1

Verify that all segments operate. +5V ±5% +37V ±5% Goes low brieﬂy on power up, then

Use front panel display test. Digital +5V supply. Display +37V supply. Microcontroller RESET.

goes high.

U401, pin 43

U401, pin 32

U401, pin 33

4MHz square wave. Pulse train every 1msec. Brief pulse train when front panel

Controller 4MHz clock. Control from main processor. Key down data sent to main processor.

key is pressed.

Power supply checks

Power supply problems can be checked using Table 4-4.

Table 4-4

Power supply checks

Step Item/component Required condition Remarks

Line fuse

Line voltage

Line power

+5VD pad

+3.3VD pad

+2.5VD pad

+1.8VD pad

U101, pin 7

U125, pin 3

U119, pin 3

U124, pin 3

U144, pin 2

C293 negative terminal

Check continuity. 120V/240V as required. Plugged into live receptacle, power on. +5V ±5% +3.3V ±5% +2.5V ±5% +1.8V ±5% +37V ±5% +15V ±5%

-15V ±5% +5V ±5%

Remove to check. Check power module position. Check for correct power-up sequence. +5VD, referenced to Common D. +3.3VD, referenced to Common D. +2.5VD, referenced to Common D. +1.8VD, 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

1 1 2

4-14 Troubleshooting Model 2701 Service Manual

Digital circuitry checks

Digital circuit problems can be checked using Table 4-5.

Table 4-5

Digital circuitry checks

Step Item/component Required condition Remarks

Power-on test

J1, pin 3

J1, pin 9

U4, pin 9

J900, pin 1

U1, pin 149

U1, lines A0-A24

U1, lines D0-D31

U1, pin 174

U15, pin 13

U15, pin 14

TP8

RAM OK, ROM OK. Digital common. +3.3V (+3.3VD supply) +4.2V +4.2V Low on power-up, then goes high. Check for stuck bits. Check for stuck bits. 50MHz Pulse train during RS-232 I/O. Pulse train during RS-232 I/O. 500Hz signal.

Verify that RAM and ROM are functional. All signals referenced to digital common. MPU supply voltage. Battery backed memory charge voltage. Battery voltage (BA-52). MPU RESET line. MPU address bus. MPU data bus. MPU clock. RS-232 RX line. RS-232 TX line. Signal present if main code is running properly.

Analog signal switching states

Table 4-6 through Table 4-12 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 4-6

DCV signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108

Q14/ Q13

100mV 1V 10V 100V 1000V

* K101 set states: Pin 8 switched to Pin 7

ON ON ON OFF OFF

Pin 3 switched to Pin 4

OFF OFF OFF ON ON

OFF OFF OFF OFF OFF

SET SET SET SET SET

OFF OFF OFF OFF OFF

ON ON ON OFF OFF

OFF OFF OFF ON ON

OFF OFF ON OFF OFF

Model 2701 Service Manual Troubleshooting 4-15

Table 4-7

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

RESET

K101 and K102 set states: Pin 8 switched to Pin 7

RESET

RESET RESET SET SET SET

Pin 3 switched to Pin 2

Pin 3 switched to Pin 4

pin 8

ON ON OFF OFF OFF

U103 pin 9

ON ON OFF OFF OFF

U105 pin 9

OFF OFF ON ON ON

U105 pin 8

OFF OFF OFF OFF ON

U103 pin 16

OFF ON OFF ON OFF

U103 pin 1

ON OFF ON OFF OFF

U105 pin 1

ON OFF ON OFF OFF

U111 pin 16

OFF OFF OFF OFF OFF

Table 4-8

Ω2 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* K102* Q113 Q105 Q104 Q108 Q11

100Ω 1kΩ 10kΩ 100kΩ 1MΩ 10MΩ 100MΩ

ON ON ON ON ON ON ON

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

ON ON ON OFF OFF ON ON

* K101 set states: Pin 8 switched to Pin 7

Pin 3 switched to Pin 4

K102 reset states: Pin 8 switched to Pin 9

Pin 3 switched to Pin 2

4-16 Troubleshooting Model 2701 Service Manual

Table 4-9

Ω4 signal switching

Range Q101 Q102 Q114 Q136 Q109 K101* Q113 Q105 Q104 Q108 Q11

100Ω 1kΩ 10kΩ 100kΩ 1MΩ 10MΩ 100MΩ

* K101 set states: Pin 8 switched to Pin 7

ON ON ON ON ON ON ON

OFF OFF OFF OFF OFF OFF OFF

Pin 3 switched to Pin 4

OFF OFF OFF OFF OFF OFF OFF

Table 4-10

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

Table 4-11

DCA signal switching

OFF OFF OFF OFF OFF ON ON

ON ON ON OFF OFF ON ON

SET SET SET SET SET SET SET

ON ON OFF OFF OFF OFF OFF

ON ON ON ON ON OFF OFF

ON ON OFF OFF OFF OFF OFF

OFF OFF OFF OFF OFF ON ON

OFF OFF ON ON ON ON ON

OFF OFF OFF OFF OFF OFF OFF

OFF OFF ON ON ON ON ON

OFF OFF OFF OFF OFF OFF OFF

ON ON ON OFF OFF ON ON

ON ON ON ON ON OFF OFF

Range K103*

20mA 100mA 1A 3A

* K103 set states: Pin 8 to 7

Pin 3 to 4 K103 reset states: Pin 8 to 9 Pin 3 to 2

Set Reset Reset Reset

Model 2701 Service Manual Troubleshooting 4-17

Table 4-12

ACA signal switching

Range K103*

1A 3A

* K103 set states: Pin 8 to 7

Pin 3 to 4 K103 reset states: Pin 8 to 9 Pin 3 to 2

Reset Reset

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

Table 4-13 through Table 4-17 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 4-13

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

Gain (U166)

×100 ×10 ×1 ×10 ×1

Table 4-14

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

Gain (U166)

4-18 Troubleshooting Model 2701 Service Manual

Table 4-15

DCA signal multiplexing and gain

Range

20mA 100mA 1A 3A

Signal (U163)

S6 S6 S6 S6

U129 pin 1

OFF OFF OFF OFF

Table 4-16

Ω2 signal multiplexing and gain

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 4-17

Ω4 signal multiplexing and gain

U129 pin 8

OFF OFF OFF ON

U129 pin 8

OFF ON ON ON OFF OFF OFF

U129 pin 9

ON ON ON OFF

U129 pin 9

ON OFF OFF OFF OFF OFF OFF

Gain (U166)

×100 ×100 ×100 ×10

Gain (U166)

×100 ×10 ×10 ×10 ×1 ×1 ×1

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 9

ON OFF OFF OFF OFF OFF OFF

Gain (U166)

×100 ×10 ×10 ×10 ×1 ×1 ×1

Model 2701 Service Manual Troubleshooting 4-19

Figure 4-3 provides a block diagram of the analog circuitry. Table 4-18 shows where the

various switching devices are located in the block diagram.

Table 4-18

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, Q119, 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

Disassembly

5-2 Disassembly Model 2701 Service Manual

Introduction

This section explains how to handle, clean, and disassemble the Model 2701 Ethernet 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.

Model 2701 Service Manual Disassembly 5-3

Static sensitive devices

CMOS devices operate at very high impedance levels. Therefore, any static that builds up on you or your clothing may be sufﬁcient to destroy these devices if they are not handled properly. Use the following precautions to avoid damaging them:

CAUTION Many CMOS devices are installed in the Model 2701. Handle all

semiconductor devices as being static sensitive.

•Transport and handle ICs only in containers specially designed to prevent static buildup. Typically, you will receive these parts in anti-static containers made of plastic or foam. Keep these devices in their original containers until ready for installation.

• Remove the devices from their protective containers only at a properly grounded work station. Also, ground yourself with a suitable wrist strap.

• Handle the devices only by the body; do not touch the pins.

• Ground any printed circuit board into which a semiconductor device is to be inserted to the bench or table.

• Use only anti-static type desoldering tools.

• Use only grounded-tip soldering irons.

• Once the device is installed in the PC board, it is normally adequately protected, and you can handle the boards normally.

Assembly drawings

Use the following assembly drawings to assist you as you disassemble and reassemble the Model 2701. Also, refer to these drawings for information about the Keithley part numbers of most mechanical parts in the unit. The drawings are located at the end of this section.

• Front Panel Assembly — 2701-040

• Card Cage/Power Module Assembly — 2701-050

•Power Module/Transformer/Chassis Assembly — 2701-051

• Front Panel/Card Cage/Chassis Assembly — 2701-052

• Chassis Assembly — 2701-053, 2701-054

• Final Inspection — 2701-080

5-4 Disassembly Model 2701 Service Manual

Disassembly procedures

Case cover removal

Follow the steps below to remove the case cover to gain access to internal parts.

WARNING Before removing the case cover, disconnect the line cord and any test leads

from the instrument.

1. Remove Handle — The handle serves as an adjustable tilt-bail. Adjust its position by gently pulling it away from the sides of the instrument case and swinging it up or down. To remove the handle, swing the handle below the bottom surface of the case and back until the orientation arrows on the handles line up with the orientation arrows on the mounting ears. With the arrows lined up, pull the ends of the handle away from the case.

2. Remove Mounting Ears — Remove the screw that secures each mounting ear. Pull down and out on each mounting ear.

NOTE When re-installing the mounting ears, make sure to mount the right ear to the right

side of the chassis and the left ear to the left side of the chassis. Each ear is marked “RIGHT” or “LEFT” on its inside surface.

3. Remove Rear Bezel — To remove the rear bezel, loosen the two captive screws that secure the rear bezel to the chassis. Pull the bezel away from the case.

4. Removing Bottom Screws — Remove the four bottom screws that secure the case to the chassis.

5. Remove Cover — To remove the case, grasp the front bezel of the instrument and carefully slide the chassis forward. Slide the chassis out of the metal case.

Motherboard removal

Perform the following steps to remove the motherboard. This procedure assumes that the

case cover is already removed.

1. Remove the RS-232 and Digital I/O fasteners. The RS-232 and Digital I/O connectors each have two nuts that secure the connectors to

the rear panel. Remove these nuts.

2. Remove the front/rear inputs switch rod. At the switch, place the edge of a ﬂat-blade screwdriver in the notch on the pushrod.

Gently twist the screwdriver while pulling the rod from the shaft.

3. Disconnect the front input terminals. You must disconnect these input terminal connections:

• INPUT HI and LO

• SENSE HI and LO

• AMPS

Keithley 2701 User guide

Specifications and Main Features

Frequently Asked Questions

User Manual