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Keysight 34970A/34972A Data Acquisition/Switch Unit

Service Guide

Notices

CAUTION

WARNING

duced in any form or by any means (including electronic storage and retrieval or translation into a foreign language) without prior agreement and written consent from Keysight Technologies as governed by United States and international copyright laws.

Manual Part Number

34972-90010

Edition

Edition 7, April 2019

Printed in:

Printed in Malaysia

Published by:

Keysight Technologies Bayan Lepas Free Industrial Zone, 11900 Penang, Malaysia

Trademarks

Adobe, the Adobe Logo, Acrobat and the Acrobat Logo are trademarks of Adobe Systems Incorporated.

Microsoft is either a registered trademark or a trademark of Microsoft Corporation in the United States and/or other countries.

Windows and MS Windows are U.S. registered trademarks of Microsoft Corporation.

Technology Licenses

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.

Declaration of Conformity

Declarations of Conformity for this product and for other Keysight products may be downloaded from the Web. Go to http://www.keysight.com/

go/conformity. You can then search by

product number to find the latest Declaration of Conformity.

U.S. Government Rights

The Software is “commercial computer software,” as defined by Federal Acquisition Regulation (“FAR”) 2.101. Pursuant to FAR 12.212 and 27.405-3 and Department of Defense FAR Supplement (“DFARS”) 227.7202, the U.S. government acquires commercial computer software under the same terms by which the software is customarily provided to the public. Accordingly, Keysight provides the Software to U.S. government customers under its standard commercial license, which is embodied in its End User License Agreement (EULA), a copy of which can be found at http://www.keysight.com/

find/sweula. The license set forth in the

EULA represents the exclusive authority by which the U.S. government may use, modify, distribute, or disclose the Software. The EULA and the license set forth therein, does not require or permit, among other things, that Keysight: (1) Furnish technical information related to commercial computer software or commercial computer software documentation that is not customarily provided to the public; or (2) Relinquish to, or otherwise provide, the government rights in excess of these rights customarily provided to the public to use, modify, reproduce, release, perform, display, or disclose commercial computer software or commercial computer software documentation. No additional government requirements beyond those set forth in the EULA shall apply, except to the extent that those terms, rights, or licenses are explicitly required from all providers of commercial computer software pursuant to the FAR and the DFARS and are set forth specifically in writing elsewhere in the EULA. Keysight shall be under no obligation to update, revise or otherwise modify the Software. With respect to any technical data as defined by FAR 2.101, pursuant to FAR 12.211 and 27.404.2 and DFARS 227.7102, the U.S. government acquires no greater than Limited Rights as defined in FAR

27.401 or DFAR 227.7103-5 (c), as applicable in any technical data.

Warranty

THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED “AS IS,” AND IS SUBJECT TO BEING CHANGED, WITHOUT NOTICE, IN FUTURE EDITIONS. FURTHER, TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, KEYSIGHT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, WITH REGARD TO THIS MANUAL AND ANY INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. KEYSIGHT SHALL NOT BE LIABLE FOR ERRORS OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, USE, OR PERFORMANCE OF THIS DOCUMENT OR OF ANY INFORMATION CONTAINED HEREIN. SHOULD KEYSIGHT AND THE USER HAVE A SEPARATE WRITTEN AGREEMENT WITH WARRANTY TERMS COVERING THE MATERIAL IN THIS DOCUMENT THAT CONFLICT WITH THESE TERMS, THE WARRANTY TERMS IN THE SEPARATE AGREEMENT SHALL CONTROL.

Safety Information

A CAUTION notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.

A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated conditions are fully understood and met.

2 Keysight 34970A/34972A Service Guide

Software Updates/Licenses

Periodically, Keysight releases software updates to fix known defects and incorporate product enhancements. To search for software updates and the latest documentation for your product, go to the product page at:

A portion of the software in this product is licensed under terms of the General Public License Version 2 (“GPLv2”). The text of the license and source code can be found at:

This product utilizes Microsoft Windows CE. Keysight highly recommends that all Windows-based computers connected to Windows CE instruments utilize current anti-virus software. For more information, go to the product page at:

Keysight 34970A/34972A Service Guide 3

Safety Symbols

CAT I

The following symbols on the instrument and in the documentation indicate precautions which must be taken to maintain safe operation of the instrument.

Alternating current (AC) Frame or chassis (ground) terminal

Caution, risk of electric shock

Standby supply. Unit is not completely disconnected from AC mains when switch is off.

IEC Measurement

Caution, risk of danger (refer to this manual for specific Warning or Caution information)

Protective earth (ground) terminal

4 Keysight 34970A/34972A Service Guide

Safety Considerations

Read the information below before using this instrument.

The following general safety precautions must be observed during all phases of operation, service, and repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards for design, manufacture, and intended use of the instrument. Keysight Technologies assumes no liability for the customer’s failure to comply with these requirements.

General

Do not use this product in any manner not specified by the manufacturer. The protective features of this product may be impaired if it is used in a manner not specified in the operation instructions.

Before Applying Power

Verify that all safety precautions are taken. Make all connections to the unit before applying power and select the appropriate power line voltage on the fuse module.

Ground the Instrument

This product is provided with protective earth terminals. To minimize shock hazard, the instrument must be connected to the ac power mains through a grounded power cable, with the ground wire firmly connected to an electrical ground (safety ground) at the power outlet. Any interruption of the protective (grounding) conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury.

Do Not Operate in an Explosive Atmosphere

Do not operate the instrument in the presence of flammable gases or fumes.

Keysight 34970A/34972A Service Guide 5

Do Not Remove the Instrument Cover

NOTE

Only qualified, service-trained personal who are aware of the hazards involved should remove instrument covers. Always disconnect the power cable and any external circuits before removing the instrument cover.

Do Not Modify the Instrument

Do not install substitute parts or perform any unauthorized modification to the product. Return the product to an Keysight Sales and Service Office for service and repair to ensure that safety features are maintained.

In Case of Damage

Instruments that appear damaged or defective should be made inoperative and secured against unintended operation until they can be repaired by qualified service personnel.

Maximum transients on all inputs are limited to 1500 Vpk, referenced to earth.Measurement is rated for CAT ‘others’, and terminals are not to be connected directly to mains. Do not use this equipment to measure circuits where transient overvoltages could exceed this level.

6 Keysight 34970A/34972A Service Guide

Environmental Conditions

The 34970A/34972A is designed for indoor use and in an area with low condensation. The table below shows the general environmental requirements for this instrument.

Environmental condition Requirement

Temperature

Humidity

Altitude Up to 2000 m

Pollution degree 2

Operating condition – 0 °C to 55 °C

Operating condition – 20% to 80% RH at 40°C or less (non-condensing)

Keysight 34970A/34972A Service Guide 7

Regulatory Markings

1SM1-

The CE mark is a registered trademark of the European Community. This CE mark shows that the product complies with all the relevant European Legal Directives.

The RCM mark is a registered trademark of the Australian Communications and Media Authority.

This text indicates that the instrument is an Industrial Scientific and Medical

Group 1 Class A product (CISPER 11, Clause 4).

The CSA mark is a registered trademark of the Canadian Standards Association.

This symbol indicates the time period during which no hazardous or toxic substance elements are expected to leak or deteriorate during normal use. Forty years is the expected useful life of the product.

ICES/NMB-001 indicates that this ISM device complies with the Canadian ICES-001. Cet appareil ISM est conforme a la norme NMB-001 du Canada.

8 Keysight 34970A/34972A Service Guide

Waste Electrical and Electronic Equipment (WEEE) Directive

This instrument complies with the WEEE Directive marking requirement. This affixed product label indicates that you must not discard this electrical or electronic product in domestic household waste.

Product category

With reference to the equipment types in the WEEE directive Annex 1, this instrument is classified as a “Monitoring and Control Instrument” product.

The affixed product label is as shown below.

Do not dispose in domestic household waste.

Keysight 34970A/34972A Service Guide 9

NOTE

Unless otherwise indicated, this manual applies to all serial numbers.

The Keysight Technologies 34970A/34972A combines precision measurement capability with flexible signal connections for your production and development test systems. Three module slots are built into the rear of the instrument to accept any combination of data acquisition or switching modules. The combination of data logging and data acquisition features makes this instrument a versatile solution for your testing requirements now and in the future.

Convenient Data Logging Features

– Direct measurement of thermocouples, RTDs, thermistors, DC voltage, AC

voltage, resistance, DC current, AC current, frequency, and period

– Interval scanning with storage of up to 50,000 time-stamped readings

– Independent channel configuration with function, Mx+B scaling, and al

limits available on a per-channel basis

– Intuitive user interface with knob for quick channel selection, menu navigation,

and data entry from the front panel

– Portable, ruggedized case with non-skid feet

– BenchLink Data Logger 3 Software for Microsoft

Windows ® included

arm

Flexible Data Acquisition/Switching Features

– 6½-digit multimeter accuracy, stability, and noise rejection

– Up to 60 channels per instrument (120 single-ended channels)

– Reading rates up to 500 readings per second on a single channel and scan

rates up to 250 channels per second

– Choice of multiplexing, matrix, general-purpose Form C switching, RF

switching, digital I/O, totalize, and 16-bit analog output functions

– GPIB (IEEE-488) interface and RS-232 interface are standard on the 34970A.

Local Area Network (LAN) and Universal Serial Bus (USB) are standard on the 34972A.

–SCPI (Standard Commands for Programmable Instruments) compatibility

10 Keysight 34970A/34972A Service Guide

The Front Panel at a Glance

Denotes a menu key. See the next page for details on menu operation.

1 State Storage / Remote Interface Menus 2 Scan Start / Stop Key 3 Measurement Configuration Menu 4 Scaling Configuration Menu 5 Alarm / Alarm Output Configuration Menu 6 Scan-to-Scan Interval Menu 7 Scan List Single Step / Read Key

8 Advanced Measurement / Utility Menus 9 Low-Level Module Control Keys 10 Single-Channel Monitor On / Off Key 11 View Scanned Data, Alarms, Errors Menu 12 Shift / Local Key 13 Knob 14 Navigation Arrow Keys

Keysight 34970A/34972A Service Guide 11

The Front-Panel Menu at a Glance

Several of the front-panel keys guide you through menus to configure various parameters of the instrument (see previous page). The following steps

demonstrate the menu structure using the key.

1 Press the menu key. You are automatically guided

2 Press the same menu key again to move to the

to the first level of the menu. Rotate the knob to view the other choices on the first level of the menu.

The menu will automatically time out after about 20 seconds of inactivity. You will be returned to the operation in progress prior to entering the menu.

next item of the menu. Typically, this is where you choose parameter values for the selected operation.

12 Keysight 34970A/34972A Service Guide

3 Rotate the knob to view the choices on this level

NOTE

of the menu. When you reach the end of the list, rotate the knob in the opposite direction to view all of the other choices.

The current selection is highlighted for emphasis. All other choices are dimmed.

4 Press the same menu key again to accept the

change and exit the menu. A brief confirmation message is displayed.

Tip: To review the current configuration of a specific menu, press the menu key several times. A message NO CHANGES is displayed when you exit the menu.

Keysight 34970A/34972A Service Guide 13

Display Annunciators

SCAN

MON

VIEW Scanned readings, alarms, errors, or relay cycles are being viewed.

CONFIG Channel configuration is in progress on displayed channel.

ADRS Instrument is addressed to listen or talk over the remote interface.

RMT Instrument is in remote mode (remote interface).

ERROR

EXT Instrument is configured for an external scan interval.

ONCE

MEM (34970A) Reading memory overflow; new readings will overwrite the oldest readings.

MEM (34972A)

AUTO (34972A) USB logging is active.

LAST Viewed data is the last reading stored during most recent scan.

MIN Viewed data is the minimum reading stored during most recent scan.

MAX Viewed data is the maximum reading stored during most recent scan.

Scan is in progress or enabled. Press and hold again to turn off.

Monitor mode is enabled. Press again to turn off.

Measurement is in progress.

Hard ware or remote interface errors are detected. Press to read errors.

Scan Once mode is enabled. Press to initiate and hold key to disable.

A USB drive is connected to the instrument (annunciator on), or data is being written to or read from the USB drive (annunciator flashing).

SHIFT

4W 4-wire function is in use on displayed channel.

OC Offset compensation is enabled on displayed channel.

has been pressed. Press again to turn off.

14 Keysight 34970A/34972A Service Guide

Alarms are enabled on displayed channel.

Mx+B scaling is enabled on displayed channel.

HI or LO alarm condition has occurred on indicated alarms.

New serial number prefixes start with MY59000101 and SG59000101.

Keysight 34970A/34972A Service Guide 15

The 34970A Rear Panel at a Glance

WARNING

1 Slot Identifier (100,200, 300) 2 Ext Trig Input / Alarm Outputs / Channel

Advance Input / Channel Closed Output

3 RS-232 Interface Connector

Use the Menu to:

– Select the GPIB or RS-232 interface (see Chapter 2). – Set the GPIB address (see Chapter 2). – Set the RS-232 baud rate, parity, and flow control mode (see Chapter 2).

4 Power-Line Fuse-Holder Assembly 5 Power-Line Voltage Setting 6 Chassis Ground Screw 7 GPIB (IEEE-488) Interface Connector

For protection from electrical shock, the power cord ground must not be defeated. If only a two-contact electrical outlet is available, connect the instrument’s chassis ground screw (see above) to a good earth ground.

16 Keysight 34970A/34972A Service Guide

The 34972A Rear Panel at a Glance

 







WARNING

For serial number MY59000100 & SG59000100 and below.

Keysight 34970A/34972A Service Guide 17

1 Slot Identifier (100,200, 300) 2 Chassis Ground Screw 3 Ext Trig Input / Alarm Outputs / Channel

Advance Input / Channel Closed Output

Use the Menu to:

– Select and configure the LAN and USB interfaces (see Chapter 2).

[a] Under some conditions, while using the USB interface with the 34972A, you may experience connection or data

loss in the presence of an electrical transient from the main power line. You can re-establish the USB communication by performing a reboot (cycle power) on the instrument. You can make the USB connection less susceptible to a potential power line transient by inserting a USB hub in the connection between the computer and the instrument.

4 Power-Line Fuse-Holder Assembly 5 LAN Connector 6 USB Drive Connector

7 USB Interface Connector

[a]

For serial number MY59000101 & SG59000101 and above.

 







WARNING

18 Keysight 34970A/34972A Service Guide

1 Slot Identifier (100,200, 300) 2 Chassis Ground Screw 3 Ext Trig Input / Alarm Outputs / Channel

Advance Input / Channel Closed Output

Use the Menu to:

– Select and configure the LAN and USB interfaces (see Chapter 2).

4 Power-Line Fuse-Holder Assembly 5 LAN Connector 6 USB Drive Connector 7 USB Interface Connector

The Plug-In Modules at a Glance

For complete specifications on each plug-in modules, refer to the module sections in Chapter 1.

34901A 20-Channel Armature Multiplexer

– 20 channels of 300 V switching

– Two channels for DC or AC current measurements (100 nA to 1A)

– Built-in thermocouple reference junction

– Switching speed of up to 60 channels per second

– Connects to the internal multimeter

– For detailed information and a module diagram, see page 151.

Each of the 20 channels switches both HI and LO inputs, thus providing fully isolated inputs to the internal multimeter. The module is divided into two banks of 10 two-wire channels each. When making four-wire resistance measurements, channels from Bank A are automatically paired with channels from Bank B. Two additional fused channels are included on the module (22 channels total) for making calibrated DC or AC current measurements with the internal multimeter (external shunt resistors are not required). You can close multiple channels on this module only if you have not configured any channels to be part of the scan list. Otherwise, all channels on the module are break-before-make.

34902A 16-Channel Reed Multiplexer

– 16 channels of 300 V switching

– Built-in thermocouple reference junction

– Switching speed of up to 250 channels per second

– Connects to the internal multimeter

– For detailed information and a module diagram, see page 153.

Use this module for high-speed scanning and high-throughput automated test applications. Each of the 16 channels switches both HI and LO inputs, thus providing fully isolated inputs to the internal multimeter. The module is divided into two banks of eight two-wire channels each. When making four-wire resistance measurements, channels from Bank A are automatically paired with channels from Bank B. You can close multiple channels on this module only if you

Keysight 34970A/34972A Service Guide 19

have not configured any channels to be part of the scan list. Otherwise, all channels on the module are break-before-make.

34903A 20-Channel Actuator / General-Purpose Switch

– 300 V, 1 A actuation and switching

– SPDT (Form C) latching relays

– Breadboard area for custom circuits

– For detailed information and a module diagram, see page 155.

Use this module for those applications that require high-integrity contacts or quality connections of non-multiplexed signals. This module can switch 300 V, 1 A (50 W maximum switch power) to your device under test or to actuate external devices. Screw terminals on the module provide access to the Normally-Open, Normally-Closed, and Common contacts for each of the 20 switches. A breadboard area is provided near the screw terminals to implement custom circuitry, such as simple filters, snubbers, or voltage dividers.

34904A 4x8 Two-Wire Matrix Switch

– 32 two-wire crosspoints

– Any combination of inputs and outputs can be connected at a time

– 300 V, 1 A switching

– For detailed information and a module diagram, see page 156.

Use this module to connect multiple instruments to multiple points on your device under test at the same time. You can connect rows and columns between multiple modules to build larger matrices such as 8x8 and 4x16, with up to 96 crosspoints in a single mainframe.

34905/6A Dual 4-Channel RF Multiplexers

– 34905A (50Ω) / 34906A (75Ω)

– 2 GHz bandwidth with on-board SMB connections

– 1 GHz bandwidth with SMB-to-BNC adapter cables provided

– For detailed information and a module diagram, see page 158.

20 Keysight 34970A/34972A Service Guide

These modules offer wideband switching capabilities for high frequency and pulsed signals. Each module is organized in two independent banks of 4-to-1 multiplexers. Both modules offer low crosstalk and excellent insertion loss performance. To create larger RF multiplexers, you can cascade multiple banks together. Only one channel in each bank may be closed at a time.

34907A Multifunction Module

– Two 8-bit Digital Input/Output ports, 400 mA sink, 42 V open collector

– 100 kHz Totalize input with 1 Vpp sensitivity

– Two 16-bit, ±12 V Calibrated Analog Outputs

– For detailed information and module block diagrams, see page 162.

Use this module to sense status and control external devices such as solenoids, power relays, and microwave switches. For greater flexibility, you can read digital inputs and the count on the totalizer during a scan.

34908A 40-Channel Single-Ended Multiplexer

– 40 channels of 300 V single-ended (common LO) switching

– Built-in thermocouple reference junction

– Switching speed of up to 60 channels per second

– Connects to the internal multimeter

– For detailed information and a module diagram, see page 160.

Use this module for high-density switching applications which require single-wire inputs with a common LO. All relays are break-before-make to ensure that only one relay is connected at any time.

Keysight 34970A/34972A Service Guide 21

In This Book

Specifications

and plug-in modules.

Quick Start

front-panel features.

Front-Panel Overview

describes some of the instrument’s menu features.

Calibration Procedures

adjustment procedures for the instrument.

Theory of Operation

to the operation the instrument.

Service

Technologies for servicing, or for servicing it yourself. It also contains a list of replaceable parts.

If you have questions relating to the operation of the 34970A/34972A, call 1-800-452-4844 in the United States, or contact your nearest Keysight Technologies Sales Office.

If your 34970A/34972A fails within one year of original purchase, Keysight will replace it free of charge. Call 1-800-829-4444 and select “Option 3” followed by “Option 1”.

Chapter 6 provides guidelines for returning your instrument to Keysight

Chapter 1 lists the technical specifications for the mainframe

Chapter 2 helps you get familiar with a few of the instrument’s

Chapter 3 introduces you to the front-panel menus and

Chapter 4 provides calibration, verification, and

Chapter 5 describes block and circuit level theory related

22 Keysight 34970A/34972A Service Guide

Software Updates/Licenses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3

Safety Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Before Applying Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Ground the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Do Not Operate in an Explosive Atmosphere . . . . . . . . . . . . . . . . . . .5

Do Not Remove the Instrument Cover . . . . . . . . . . . . . . . . . . . . . . . .6

Do Not Modify the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

In Case of Damage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Environmental Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Regulatory Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

Waste Electrical and Electronic Equipment (WEEE) Directive . . . . . . . .9

Product category . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Sales and Technical Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9

The Front Panel at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11

The Front-Panel Menu at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . .12

Display Annunciators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14

The 34970A Rear Panel at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . .16

The 34972A Rear Panel at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . .17

The 34972A Rear Panel at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . .18

The Plug-In Modules at a Glance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

In This Book . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22

1Specifications

2Quick Start

Quick Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

To Prepare the Instrument for Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33

To Connect Wiring to a Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34

Keysight 34970A/34972A Service Guide 23

To Set the Time and Date . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

To Configure a Measurement Channel . . . . . . . . . . . . . . . . . . . . . . . . . 37

To Monitor a Single Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

To Close a Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

If the Instrument Does Not Turn On . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

To Adjust the Carrying Handle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

To Rack Mount the Instrument . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3 Front-Panel Overview

Front-Panel Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Front-Panel Menu Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

To Unsecure for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

To Secure Against Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

To Change the Security Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

To Perform a Zero Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

To Apply Mx+B Scaling to Measurements . . . . . . . . . . . . . . . . . . . . . . . 57

To Read the Relay Cycle Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

To Read a Digital Input Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

To Write to a Digital Output Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60

To Read the Totalizer Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

To Output a DC Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

4 Calibration Procedures

Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

Keysight Technologies Calibration Services . . . . . . . . . . . . . . . . . . . . . 66

Calibration Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Adjustment is Recommended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Time Required for Calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Automating Calibration Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

24 Keysight 34970A/34972A Service Guide

Recommended Test Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68

Input Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .69

Calibration Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71

To Unsecure the Instrument Without the Security Code . . . . . . . . .72

Calibration Message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74

Calibration Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74

Calibration Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75

Aborting a Calibration in Progress . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75

Test Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .76

Performance Verification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77

Self-Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78

Quick Performance Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79

Performance Verification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79

Internal DMM Verification Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80

Zero Offset Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80

Gain Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82

Optional AC Performance Verification Tests . . . . . . . . . . . . . . . . . . . . .87

Internal DMM Adjustments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88

Zero Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .88

Gain Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89

–10 VDC Adjustment Procedure (Optional) . . . . . . . . . . . . . . . . . . . . . .92

Plug-in Module Test Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . .94

Relay Verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

Relay Cycle Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .96

(Optional) 34901A Relay Contact Resistance Verification . . . . . . . .97

(Optional) 34902A Relay Contact Resistance Verification . . . . . . .104

(Optional) 34903A Relay Contact Resistance Verification . . . . . . .109

(Optional) 34904A Relay Contact Resistance Verification . . . . . . .110

(Optional) 34905/06A Relay Contact Resistance Verification . . . .113

(Optional) 34908A Relay Contact Resistance Verification . . . . . . .114

Thermocouple Reference Junction (Optional) . . . . . . . . . . . . . . . . . . .120

Thermocouple Reference Junction Verification . . . . . . . . . . . . . . .120

Keysight 34970A/34972A Service Guide 25

Thermocouple Reference Junction Adjustments . . . . . . . . . . . . . . 121

34907A Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Analog Output Verification Test . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Analog Output Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124

5Theory of Operation

Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

System Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

Floating Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 128

Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

Earth-Referenced Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Power Supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Front Panel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

Backplane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Analog Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Digital Bus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136

Internal DMM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

DMM Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138

Input Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139

Ohms Current Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

AC Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142

A-to-D Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Switch Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146

Switch Module Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Relay Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149

34901A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151

34902A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153

34903A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155

34904A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156

34905A/34906A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158

34908A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Multifunction Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162

26 Keysight 34970A/34972A Service Guide

Multifunction Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .162

Totalizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .164

Analog Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165

Digital I/O . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .166

6Service

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170

Operating Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171

Types of Service Available . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172

Repackaging for Shipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173

Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173

Electrostatic Discharge (ESD) Precautions . . . . . . . . . . . . . . . . . . . . .174

Surface Mount Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174

To Replace the Power-Line Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175

Troubleshooting Hints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175

Self-Test Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .179

Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184

General Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .185

Internal DMM Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .186

Front Panel Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187

Additional Chassis Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . .188

Plug-In Module Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

Recyclable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191

Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194

To Order Replaceable Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .194

Parts List for 34970A/34972A and 34901A . . . . . . . . . . . . . . . . . .194

Keysight 34970A/34972A Service Guide 27

THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.

28 Keysight 34970A/34972A Service Guide

Keysight 34970A/34972A Data Acquisition/Switch Unit Service Guide

1 Specifications

For the specifications and characteristics of the 34970A/34972A Data Acquisition/Switch Unit, refer to the datasheet at

http://literature.cdn.keysight.com/litweb/pdf/5965-5290EN.pdf

1 Specifications

THIS PAGE HAS BEEN INTENTIONALLY LEFT BLANK.

30 Keysight 34970A/34972A Service Guide

Keysight 34970A/34972A Data Acquisition/Switch Unit Service Guide

2 Quick Start

Quick Start 32

To Prepare the Instrument for Use 33

To Connect Wiring to a Module 34

To Set the Time and Date 36

To Configure a Measurement Channel 37

To Monitor a Single Channel 38

To Close a Channel 39

If the Instrument Does Not Turn On 41

To Adjust the Carrying Handle 44

To Rack Mount the Instrument 45

2Quick Start

Quick Start

One of the first things to do with your instrument is to become acquainted with the front panel. We have written the exercises in this chapter to prepare the instrument for use and help you get familiar with some of its front-panel operations.

The front panel has several groups of keys to select various functions and operations. A few keys have a shifted function printed in blue below the key. To

perform a shifted function, press (the SHIFT annunciator will turn on). Then, press the key that has the desired label below it. For example, to select the Utility

Menu, press .

If you accidentally press , just press it again to turn off the SHIFT annunciator.

This chapter is divided into the following sections:

– “To Prepare the Instrument for Use” on page 33

– “To Connect Wiring to a Module” on page 34

– “To Set the Time and Date” on page 36

– “To Configure a Measurement Channel” on page 37

– “To Monitor a Single Channel” on page 38

– “To Close a Channel” on page 39

– “If the Instrument Does Not Turn On” on page 41

– “” on page 43

– “To Rack Mount the Instrument” on page 45

32 Keysight 34970A/34972A Service Guide

To Prepare the Instrument for Use

1 Check the list of supplied items.

Verify that you have received the following items with your instrument. If

anything is missing, contact your nearest Keysight Technologies Sales Office.

–One power cord.

–One User’s Guide.

–This Service Guide.

–One Quick Reference Guide.

– Certificate of Calibration (if you ordered the internal DMM).

– BenchLink Data Logger 3 Software CD-ROM.

– Quick Start Package (if you ordered the internal DMM):

– One RS-232 cable.

– One J-type thermocouple and a flatblade screwdriver.

– Any plug-in modules that you ordered are delivered in a separate shipping

container.

2 Verify that the fuse on the back is set to the proper voltage range for your

AC power.

3 Connect the power cord and turn on the instrument.

Quick Start 2

The front-panel display will light up briefly while the instrument performs its

power-on self-test. The instrument initially powers up with all measurement

channels turned off. To review the power-on display with all annunciators

turned on, hold down

does not turn on properly, see page 41.

4 Perform a complete self-test.

The complete self-test performs a more extensive set of tests than those

performed at power-on. Hold down as you turn on the instrument and

hold down the key until you hear a long beep. The self-test will begin when

you release the key following the beep.

Keysight 34970A/34972A Service Guide 33

as you turn on the instrument. If the instrument

2Quick Start

– For detailed information on each module, refer to the

34970A/34972A User’s Guide.

– To reduce wear on the internal DMM relays, wire like

functions on adjacent channels.

– Use shielded twisted pair PTFE insulated cables to

reduce settling and noise errors.

– The diagrams on the next page show how to connect

wiring to a multiplexer module for each measurement function.

20 AWG Typical

6 mm

4 Replace the module cover.

2 Connect wiring to the screw terminals.

Wiring Hints...

Slot Channel

Channel Number:

1 Remove the module cover.

3 Route wiring through strain relief.

5 Install the module into mainframe.

Cable Tie Wrap

(optional)

To Connect Wiring to a Module

34 Keysight 34970A/34972A Service Guide

Quick Start 2

Thermocouple

2-Wire Ohms / RTD / Thermistor

Thermocouple Types: B, E, J, K, N, R, S, T

See the 34970A/34972A User’s Guide for

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 M

RTD Types: 0.00385, 0.00391 Thermistor Types, 2.2 k, 5 k, 10 k

DC Current / AC Current

Valid only on channels 21 and 22 on the 34901A

Ranges: 10 mA, 100 mA, 1A

Channel n (source) is automatically paired with Channel n +10 (sense) on the 34901A, or

Channel n +8 (sense) on the 34902A.

Ranges: 100, 1 k, 10 k, 100 k, 1 M, 10 M, 100 MΩ RTD Types: 0.00385, 0.00391

DC Voltage / AC Voltage / Frequency

Ranges: 100 mV, 1 V, 10 V, 100 V, 300 V

4-Wire Ohms / RTD

thermocouple color codes.

Keysight 34970A/34972A Service Guide 35

2Quick Start

To Set the Time and Date

All readings during a scan are automatically time stamped and stored in non-volatile memory. In addition, alarm data is time stamped and stored in a separate non-volatile memory queue.

1 Set the time of day.

Use and to select the field to modify and turn the knob to change the value. You can also edit the AM/PM field.

TIME 03:45 PM

2 Set the date.

Use and to select the field to modify and turn the knob to change the value.

JUN 01 2002

36 Keysight 34970A/34972A Service Guide

To Configure a Measurement Channel

NOTE

Use this general procedure to configure a measurement channel.

1 Select the channel.

Turn the knob until the desired channel is shown on the right side of

front-panel display. The channel number is a three-digit number; the left-most

digit represents the slot number (100, 200, or 300) and the two digits on the

right indicate the channel number (102, 110, etc.).

You can use and to skip to the beginning of the previous or next slot.

2 Select the measurement parameters for the selected channel.

Use the knob to scroll through the measurement choices on each level of the

menu. When you press to make your selection, the menu automatically

guides you through all relevant choices to configure a measurement on the

selected function. When you have finished configuring the parameters, you are

automatically exited from the menu.

The present selection (or default) is displayed in full bright for easy

identification. When you make a different selection, the new choice is shown in

full bright and it becomes the default selection. The order of the choices

always remains the same; however, you always enter the menu at the current

(full bright) setting for each parameter.

Quick Start 2

The menu will time-out after about 20 seconds of inactivity and any changes made previously will take effect.

Keysight 34970A/34972A Service Guide 37

2Quick Start

To Monitor a Single Channel

You can use the Monitor function to continuously take readings on a single channel, even during a scan. This feature is used during front panel calibration procedures.

1 Select the channel to be monitored.

Only one channel can be monitored at a time but you can change the channel being monitored at any time by turning the knob.

2 Enable monitoring on the selected channel.

Any channel that can be “read” by the instrument can be monitored (the MON annunciator turns on). This includes any combination of temperature, voltage, resistance, current, frequency, or period measurements on multiplexer channels. You can also monitor a digital input port or the totalizer count on the multifunction module.

To disable monitoring, press again.

38 Keysight 34970A/34972A Service Guide

To Close a Channel

NOTE

On the multiplexer and switch modules, you can close and open individual relays on the module. However, note that if you have already configured any multiplexer channels for scanning, you cannot independently close and open individual relays on that module.

1 Select the channel.

Turn the knob until the desired channel is shown on the right side of

front-panel display. For this example, select channel 213.

2 Close the selected channel.

3 Open the selected channel.

will sequentially open all channels on the mod ule in the selected slot.

The table below shows the low-level control operations available for each of

the plug-in modules.

Quick Start 2

Plug-In Mod ule

34901A 20-Channel Mux YYY Y

34902A 16-Channel Mux YYY Y

34908A 40-Channel Single-Ended Mux

34903A 20-Channel Actuator YY

34904A 4x8 Matrix YY

34905A Dual 4-Channel RF Mux (50Ω)

34906A Dual 4-Channel RF Mux (75Ω)

34907A Multifunction Module (DIO) YY Y

[a]

[b]

YYY Y

Keysight 34970A/34972A Service Guide 39

2Quick Start

Plug-In Mod ule

34907A Multifunction Module (Totalizer) YY

34907A multifunction Module (DAC) Y

[a] Only one channel can be closed at a time on this module.

[b] Only one channel in each bank can be closed at a time on this module.

40 Keysight 34970A/34972A Service Guide

If the Instrument Does Not Turn On

NOTE

Use the following steps to help solve problems you might encounter when turning on the instrument.

1 Verify that there is AC power to the instrument.

First, verify that the power cord is firmly plugged into the power receptacle on

the rear panel of the instrument. You should also make sure that the power

source you plugged the instrument into is energized. Then, verify that the

instrument is turned on.

The On/Standby switch is located on the lower left side of the front panel.

2 Verify the power-line voltage setting.

The line voltage is set to the proper value for your country when the

instrument is shipped from the factory. Change the voltage setting if it is not

correct. The settings are: 100, 120, 220, or 240 VAC.

– For 127 VAC operation, use the 120 VAC setting.

– For 230 VAC operation, use the 220 VAC setting.

Quick Start 2

See the next page if you need to change the line voltage setting.

3 Verify that the power-line fuse is good.

The instrument is shipped from the factory with a 500 mA fuse installed. This is

the correct fuse for all line voltages.

See the next page if you need to replace the power-line fuse.

To replace the 500 mAT, 250 V fuse, order Keysight part number 2110-0458.

Keysight 34970A/34972A Service Guide 41

2Quick Start

3 Rotate the line-voltage selector until the correct voltage appears in the window.

1 Remove the power cord. Remove the fuse-holder assembly from the rear panel.

100, 120 (127), 220 (230), or 240 VAC

2 Remove the line voltage selector from the assembly.

4 Replace the fuse-holder assembly in the rear panel.

Fuse: 500 mAT (for all line voltages) Keysight Part Number: 2110-0458

Verify that the correct line voltage is selected and the power-line fuse is good.

42 Keysight 34970A/34972A Service Guide

Quick Start 2

1 Remove the power cord. Remove the fuse-holder assembly from the rear panel.

3 Replace the fuse-holder assembly in the rear panel.

2 Remove the fuse from the assembly.

Fuse: 250 maT (for all line voltages)

Keysight Part Number: 2110-1704

New serial number prefixes start with MY59000101 and SG59000101.

Keysight 34970A/34972A Service Guide 43

2Quick Start

Bench-top viewing position Carrying position

To Adjust the Carrying Handle

To adjust the position, grasp the handle by the sides and pull outward. Then, rotate the handle to the desired position.

44 Keysight 34970A/34972A Service Guide

To Rack Mount the Instrument

NOTE

To remove the handle, rotate it to the vertical position and pull the ends outward.

Front Rear (bottom view)

To remove the rubber bumper, stretch a corner and then slide it off.

You can mount the instrument in a standard 19-inch rack cabinet using one of three optional kits available. Instructions and mounting hardware are included with each rack-mounting kit. Any Keysight System II instrument of the same size can be rack-mounted beside the 34970A/34972A.

Remove the carrying handle, and the front and rear rubber bumpers, before rack-mounting the instrument.

Quick Start 2

Keysight 34970A/34972A Service Guide 45

2Quick Start

To rack mount a single instrument, order adapter kit 5063-9240.

To rack mount two instruments side-by-side, order lock-link kit 5061-9694 and flange kit 5063-9212. Be sure to use the support rails inside the rack cabinet.

To install one or two instruments in a sliding support shel f, order shelf 5063-9255, and slide kit 1494-0015 (for a single instrument, also order filler panel 5002-3999).

46 Keysight 34970A/34972A Service Guide

Keysight 34970A/34972A Data Acquisition/Switch Unit Service Guide

3 Front-Panel Overview

Front-Panel Overview 48

Front-Panel Menu Reference 49

To Unsecure for Calibration 52

To Secure Against Calibration 53

To Change the Security Code 54

Error Messages 55

To Perform a Zero Adjustment 56

To Apply Mx+B Scaling to Measurements 57

To Read the Relay Cycle Count 58

To Read a Digital Input Port 59

To Write to a Digital Output Port 60

To Read the Totalizer Count 61

To Output a DC Voltage 62

3 Front-Panel Overview

Front-Panel Overview

This chapter introduces you to the front-panel keys and menu operation. This chapter does not give a detailed description of every front-panel key or menu operation. It does, however, give you an overview of the front-panel menus and many front-panel operations. See the Keysight 34970A/34972A User’s Guide for a complete discussion of the instrument’s capabilities and operation.

This chapter is divided into the following sections:

– “Front-Panel Menu Reference” on page 49

– “To Unsecure for Calibration” on page 52

– “To Secure Against Calibration” on page 53

– “To Change the Security Code” on page 54

– “Error Messages” on page 55

– “To Perform a Zero Adjustment” on page 56

– “To Apply Mx+B Scaling to Measurements” on page 57

– “To Read the Relay Cycle Count” on page 58

– “To Read a Digital Input Port” on page 59

– “To Write to a Digital Output Port” on page 60

– “To Read the Totalizer Count” on page 61

– “To Output a DC Voltage” on page 62

48 Keysight 34970A/34972A Service Guide

Front-Panel Menu Reference

This section gives an overview of the front-panel menus. The menus are designed to automatically guide you through all parameters required to configure a particular function or operation. The remainder of this chapter contains examples of using the front-panel menus. New serial number prefixes start with MY59000101 and SG59000101.

Configure the measurement parameters on the displayed channel.

– Select the measurement function (dc volts, ohms, etc.) on the displayed channel. – Select transducer type for temperature measurements. – Select units (°C, °F, or K) for temperature measurements. – Select measurement range or autorange. – Select measurement resolution. – Copy and paste measurement configuration to other channels.

Configure the scaling parameters for the d isplayed channel.

Front-Panel Overview 3

– Set the gain (“M”) and offset (“B”) value for the displayed channel. – Make a null measurement and store it as the offset value. – Specify a custom label (RPM, PSI, etc.) for the displayed channel.

Configure alarms on the d isplayed channel.

– Select one of four alarms to report alarm conditions on the displayed channel. – Configure a high limit, low limit, or both for the displayed channel. – Configure a bit pattern that will generate an alarm (digital input only).

Keysight 34970A/34972A Service Guide 49

3 Front-Panel Overview

Configure the four Alarm Output hardware lines.

– Clear the state of the four alarm output lines. – Select the “Latch” or “Track” mode for the four alarm output lines. – Select the slope (rising or falling edge) for the four alarm output lines.

Configure the event or action that controls the scan interval.

– Select the scan interval mode (interval, manual, external, or alarm). – Select the scan count.

Configure the advanced measurement features on displayed channel.

– Set the integration time for measurements on the displayed channel. – Set the channel-to-channel delay for scanning. – Enable/disable the thermocouple check feature (T/C measurements only). – Select the reference junction source (T/C measurements only). – Set the low frequency limit (ac measurements only). – Enable/disable offset compensation (resistance measurements only). – Select the binary or decimal mode for digital operations (34907A only). – Configure the totalizer reset mode (totalizer only). – Select which edge is detected (rising or falling) for totalizer operations.

Configure system-related instrument parameters.

– Set the real-time system clock and calendar. – Query the firmware revisions for the mainframe and installed modules. – Select the instrument’s power-on configuration (last or factory reset). – Enable/disable the internal DMM. – Secure/unsecure the instrument for calibration.

50 Keysight 34970A/34972A Service Guide

Front-Panel Overview 3

View readings, alarms, and errors.

– View the last 100 scanned readings from memory (last, min, max, and average). – View the first 20 alarms in the alarm queue (reading and time alarm occurred). – View up to 10 errors (34970A) or 20 errors (34972A) in the error queue. – Read the number of cycles for the displayed relay (relay maintenance feature).

Store and recall instrument states.

– Store up to five instrument states in non-volatile memory. – Assign a name to each storage location. – Recall stored states, power-down state, factory reset state, or preset state.

Configure the remote interface (34970A).

– Select the GPIB address. – Configure the RS-232 interface (baud rate, parity, and flow control).

Configure the remote interface (34972A).

– Configure the LAN settings (IP Address, Hostname, DHCP, etc.) – Configure the USB settings (Enable, USB ID, etc.) – Configure and use the USB drive (Logging, etc.)

Keysight 34970A/34972A Service Guide 51

3 Front-Panel Overview

NOTE

To Unsecure for Calibration

You can unsecure the instrument either from the front panel or over the remote interface. The instrument is secured when shipped from the factory and the security code is set to “HP034970” or “AT034972”, depending on the product number.

– Once you enter a security code, that code must be used for both front-panel

and remote operation. For example if you secure the instrument from the front panel, you must use that same code to unsecure it from the remote interface.

– Press to enter the Utility menu.

When you first enter the Utility menu, the calibration entries toggle between CAL

SECURED and UNSECURE CAL. To unsecure the instrument, select UNSECURE CAL and press . After entering the correct security code, press

When you return to the menu, you will see new choices CAL UNSECURED and SECURE CAL.

If you enter the wrong secure code, NO MATCH is displayed and a new choice, EXIT, is shown.

again.

52 Keysight 34970A/34972A Service Guide

To Secure Against Calibration

You can secure the instrument either from the front panel or over the remote interface. The instrument is secured when shipped from the factory and the security code is set to “HP034970” or “AT034972”, depending on the product number.

– Once you enter a security code, that code must be used for both front-panel

and remote operation. For example if you secure the instrument from the front

panel, you must use that same code to unsecure it from the remote interface.

– Press

When you enter the Utility menu, the calibration entries toggle between CAL UNSECURED and SECURE CAL. To secure the instrument, select SECURE CAL

and press . After entering the desired security code, press you return to the menu, you will see new choices CAL SECURED and UNSECURE

CAL.

to enter the Utility menu.

Front-Panel Overview 3

again. When

Keysight 34970A/34972A Service Guide 53

3 Front-Panel Overview

To Change the Security Code

– To change the security code, you must first unsecure the instrument, and then

enter a new code. Make sure you have read the security code rules described on page 71 before attempting to change the security code.

– To change the security code, first make sure that the instrument is unsecured.

Go to the SECURE CAL entry, enter the new security code, and press instrument is now secured with the new code). Changing the code from the front

panel also changes the code as seen from the remote interface.

(the

54 Keysight 34970A/34972A Service Guide

Error Messages

Error messages are retrieved in a first-in-first-out (FIFO) order.

Front-Panel Overview 3

When the ERROR annunciator is on, press arrow keys to scroll the message in the display.

A list of the self-test errors messages and their meanings begins on page 179.

For a complete list of error messages and descriptions, see Chapter 6 in the 34970A/34972A User’s Guide.

to view error messages. use the

Keysight 34970A/34972A Service Guide 55

3 Front-Panel Overview

To Perform a Zero Adjustment

The instrument features closed case electronic calibration. No internal mechanical adjustments are required. The instrument calculates correction factors based upon an input reference value and stores the correction factors in non-volatile memory. This procedure demonstrates making the zero adjustment from the front panel. The gain adjustments are similar.

DO NOT perform this procedure before reading Chapter 4. Chapter 4 describes this procedure, the required input connections, input signals, and test considerations required for a valid adjustment.

1 Configure the channel.

You must configure a channel before applying performing the adjustment procedure. Configure the channel to DC VOLTS and 6½ digits.

2 Apply the input signal.

In this example, the input signal is a copper short (see page 69).

3 Setup the calibration.

The display will show PERFORM CAL.

4 Set the adjustment value.

The display will show the a number. Edit the number to the actual input value. For the Zero Adjustment, the input value is 0.000000.

+000.000,000 mVDC

5 Begin the adjustment.

The display will show the progress of the adjustment. When all the adjustments are completed, the display will show done.

DONE

56 Keysight 34970A/34972A Service Guide

To Apply Mx+B Scaling to Measurements

The scaling function allows you to apply a gain and offset to all readings on a specified multiplexer channel during a scan. In addition to setting the gain (“M”) and offset (“B”) values, you can also specify a custom measurement label for your scaled readings (RPM, PSI, etc.).

1Configure the channel.

You must configure the channel (function, transducer type, etc.) before

applying any scaling values. If you change the measurement configuration,

scaling is turned off on that channel and the gain and offset values are reset

(M=1 and B=0).

2 Set the gain and offset values.

The scaling values are stored in non-volatile memory for the specified

channels. A Factory Reset turns off scaling and clears the scaling values on all

channels. An Instrument Preset or Card Reset does not clear the scaling values

and does not turn off scaling.

+1.000,000

Set Gain

Front-Panel Overview 3

-0.700,000 OHM

3 Select the custom label.

You can specify an optional three-character label for your scaled readings

(RPM, PSI, etc.). The default label is the standard engineering unit for the

selected function (VDC, OHM, etc.).

LABEL AS OHM

4 Scaling is now applied to the measurements.

Keysight 34970A/34972A Service Guide 57

Set Offset

3 Front-Panel Overview

To Read the Relay Cycle Count

The instrument has a Relay Maintenance System to help you predict relay end-of-life. The instrument counts the cycles on each relay in the instrument and stores the total count in non-volatile memory on each switch module. You can use this feature on any of the relay modules and the internal DMM.

– In addition to the channel relays, you can also query the count on backplane

relays and bank relays. Note that you cannot control the state of these relays from the front panel but you can query the count.

– You can also query the state of the three relays on the internal DMM. These

relays are numbered “1”, “2”, and “3” (which correspond to relays K102, K103, and K104 respectively). These relays open or close when a function or range is changed on a module.

– The 34908A multiplexer contains 40 channels which are switched (HI only)

using only 20 relays. Each relay is used to switch HI on two different channels (and only one channel can be closed at a time). The channels are arranged such that channels 01 and 21 use different contacts on the same relay. The remaining channels are also paired in the same manner (channels 02 and 22, channels 03 and 23, etc.). Therefore, when you query the relay count on a channel, the number reflects the number of times that the relay was closed. For example, the relay count will always be the same on channels 01 and 21.

– For more information on relay life and load considerations, refer to “Relay Life

and Preventative Maintenance” in the 34970A/34972A User’s Guide.

– To read the count on the active channel, choose the following item and then

turn the knob. To read the count on the internal DMM relays, turn the knob counterclockwise beyond the lowest numbered channel in the instrument. To read the “hidden” relays, turn the knob clockwise beyond the highest numbered channel in the current slot.

RELAY CYCLES

58 Keysight 34970A/34972A Service Guide

To Read a Digital Input Port

NOTE

The multifunction module (34907A) has two non-isolated 8-bit input/output ports which you can use for reading digital patterns. You can read the live status of the bits on the port or you can configure a scan to include a digital read.

1 Select the Digital Input port.

Select the slot containing the multifunction module and continue turning the

knob until DIN is displayed (channel 01 or 02).

2 Read the specified port.

You can specify whether you want to use binary or decimal format. Once you

have selected the number base, it is used for all input or output operations on

the same port. To change the number base, press the key and select USE

BINARY or USE DECIMAL.

Front-Panel Overview 3

01010101 DIN

The bit pattern read from the port will be displayed until you press another key,

turn the knob, or until the display times out.

To add a digital input channel to a scan list, press and select the DIO READ choice.

Binary Display Shown

Keysight 34970A/34972A Service Guide 59

3 Front-Panel Overview

To Write to a Digital Output Port

The multifunction module (34907A) has two non-isolated 8-bit input/output ports which you can use for outputting digital patterns.

1 Select the Digital Output port.

Select the slot containing the multifunction module and continue turning the knob until DIN is displayed (channel 01 or 02).

2 Enter the bit pattern editor.

Notice that the port is now converted to an output port (DOUT).

00000000 DOUT

3 Edit the bit pattern.

Use the knob and or keys to edit the individual bit values. You can specify whether you want to use binary or decimal format. Once you have selected the number base, it is used for all input or output operations on the

same port. To change the number base, press the key and select USE BINARY or USE DECIMAL.

240 DOUT

4 Output the bit pattern to the specified port.

The specified bit pattern is latched on the specified port. To cancel an output operation in progress, wait for the display to time out.

Binary Display Shown

Decimal Display Shown

60 Keysight 34970A/34972A Service Guide

To Read the Totalizer Count

NOTE

The multifunction module (34907A) has a 26-bit totalizer which can count pulses at a 100 kHz rate. You can manually read the totalizer count or you can configure a scan to read the count.

1 Select the totalizer channel.

Select the slot containing the multifunction module and continue turning the

knob until TOTALIZE is displayed (channel 03).

2 Configure the totalize mode.

The internal count starts as soon as you turn on the instrument. You can

configure the totalizer to reset the count to “0” after being read or it can count

continuously and be manually reset.

READ + RESET

3 Read the count.

The count is read once each time you press ; the count does not update

automatically on the display. As configured in this example, the count is

automatically reset to “0” each time you read it.

Front-Panel Overview 3

12345 TOT

The count will be displayed until you press another key, turn the knob, or until

the display times out. To manually reset the totalizer count, press .

To add a totalizer channel to a scan list, press and select the TOT READ choice.

Keysight 34970A/34972A Service Guide 61

3 Front-Panel Overview

To Output a DC Voltage

The multifunction module (34907A) has two analog outputs capable of outputting calibrated voltages between ±12 volts.

1 Select a DAC Output channel.

Select the slot containing the multifunction module and continue turning the knob until DAC is displayed (channel 04 or 05).

2 Enter the output voltage ed itor.

+00.000 V DAC

3 Set the desired output voltage.

Use the knob and or keys to edit the individual digits.

+05.250VDAC

4 Output the voltage from the selected DAC.

The output voltage will be displayed until you press another key or turn the knob. To manually reset the output voltage to 0 volts, press .

62 Keysight 34970A/34972A Service Guide

Keysight 34970A/34972A Data Acquisition/Switch Unit Service Guide

4 Calibration Procedures

Calibration Procedures 64

Keysight Technologies Calibration Services 66

Calibration Interval 66

Time Required for Calibration 67

Automating Calibration Procedures 67

Recommended Test Equipment 68

Input Connections 69

Calibration Security 71

Calibration Message 74

Calibration Count 74

Calibration Procedure 75

Aborting a Calibration in Progress 75

Test Considerations 76

Performance Verification Tests 77

Internal DMM Verification Tests 80

Optional AC Performance Verification Tests 87

Internal DMM Adjustments 88

–10 VDC Adjustment Procedure (Optional) 92

Plug-in Module Test Considerations 94

Relay Verification 96

Thermocouple Reference Junction (Optional) 120

34907A Analog Output 123

4 Calibration Procedures

Calibration Procedures

This chapter contains procedures for verification of the instrument’s performance and adjustment (calibration). These procedures are required only if the internal DMM is installed. The chapter is divided into the following sections:

– “Keysight Technologies Calibration Services” on page 4

– “Calibration Interval” on page 4

– “Time Required for Calibration” on page 5

– “Automating Calibration Procedures” on page 5

– “Recommended Test Equipment” on page 6

– “Input Connections” on page 7

– “Calibration Security” on page 9

– “Calibration Message” on page 12

– “Calibration Count” on page 12

– “Calibration Procedure” on page 13

– “Aborting a Calibration in Progress” on page 13

– “Test Considerations” on page 14

– “Performance Verification Tests” on page 15

– “Internal DMM Verification Tests” on page 18

– “Optional AC Performance Verification Tests” on page 25

– “Internal DMM Adjustments” on page 26

– “–10 VDC Adjustment Procedure (Optional)” on page 30

– “Plug-in Module Test Considerations” on page 32

– “Relay Verification” on page 34

– “Thermocouple Reference Junction (Optional)” on page 58

– “34907A Analog Output” on page 61

64 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

Closed-Case Electronic Calibration

The instrument features closed-case electronic calibration. No internal mechanical adjustments are required. The instrument calculates correction factors based upon the input reference value you set. The new correction factors are stored in non-volatile memory until the next calibration adjustment is performed. Non-volatile EEPROM calibration memory does not change when power has been off or after a remote interface reset.

Keysight 34970A/34972A Service Guide 65

4 Calibration Procedures

Keysight Technologies Calibration Services

When your instrument is due for calibration, contact your local Keysight Service Center for a low-cost recalibration. The 34970A/34972A is supported on automated calibration systems which allow Keysight to provide this service at competitive prices.

Calibration Interval

The instrument should be calibrated on a regular interval determined by the measurement accuracy requirements of your application.

A 1-year interval is adequate for most applications. Accuracy specifications are warranted only if adjustment is made at regular calibration intervals. Accuracy specifications are not warranted beyond the 1-year calibration interval. Keysight does not recommend extending calibration intervals beyond 2 years for any application.

Adjustment is Recommended

Whatever calibration interval you select, Keysight recommends that complete re-ad justment should always be performed at the calibration interval. This will assure that the 34970A/34972A will remain within specification for the next calibration interval. This criteria for re-adjustment provides the best long-term stability. Performance data measured using this method can be used to extend future calibration intervals.

Use the Calibration Count feature (see page 12) to verify that all adjustments have been performed.

66 Keysight 34970A/34972A Service Guide

Time Required for Calibration

The 34970A/34972A can be automatically calibrated under computer control. With computer control you can perform the complete calibration procedure and performance verification tests in less than 30 minutes once the instrument is warmed-up (see “Test Considerations” on page 14). Manual calibrations using the recommended test equipment will take approximately 2 hours.

Automating Calibration Procedures

You can automate the complete verification and adjustment procedures outlined in this chapter if you have access to programmable test equipment. You can program the instrument configurations specified for each test over the remote interface. You can then enter readback verification data into a test program and compare the results to the appropriate test limit values.

You can also adjust the instrument from the remote interface. Remote adjustment is similar to the local front-panel procedure. You can use a computer to perform the adjustment by first selecting the required function and range. The calibration value is sent to the instrument and then the calibration is initiated over the remote interface. The instrument must be unsecured prior to initiating the calibration procedure.

For further information on programming the instrument, see Chapter 5 in the 34970A/34972A User’s Guide.

Calibration Procedures 4

Keysight 34970A/34972A Service Guide 67

4 Calibration Procedures

Recommended Test Equipment

The test equipment recommended for the performance verification and adjustment procedures is listed below. If the exact instrument is not available, substitute calibration standards of equivalent accuracy.

A suggested alternate method would be to use the Keysight 3458A 8½digit Digital Multimeter to measure less accurate yet stable sources. The output value measured from the source can be entered into the instrument as the target calibration value.

Application Recommended Equipment Accuracy Requirements

Zero Calibration

DC Voltage

DC Current

Resistance

AC Voltage

AC Current

Frequency

Analog Output 34907A Keysight 34401A <1/5 instrument 24 hour spec

Thermocouple Reference Junction

34901A 34902A 34908A

[a]

Fluke 5700A <1/5 instrument 24 hour spec

Fluke 5700A/5725A <1/5 instrument 24 hour spec

Fluke 5700A <1/5 instrument 24 hour spec

Fluke 5700A/5725A <1/5 instrument 24 hour spec

Keysight 33220A <1/5 instrument 24 hour spec

Thermistor YSI 44031 (two)

J Type Calibrated Thermocouple Triple

None 4 -terminal all copper short

[b]

±0.1 °C

Point Cell

Relay contact resistance

All switch modules

[a] In addition to the internal DMM, these applications require an input multiplexer module. The Keysight 34901A is recommended.

[b] Thermistor YSI 44031 is available as Keysight part number 34308A (package of five).

Keysight 34401A ±0.001W resolution

68 Keysight 34970A/34972A Service Guide

Input Connections

Copper Short

Connections for DC/AC Current

Connections for 4-wire Ohms

Connections for DC V, AC V, 2- and 4-wire Ohms

34901A

To Calibrator

You will need an input multiplexer module to verify or adjust the internal DMM. Input connections can be made using a 34901A 20-Channel Multiplexer.

To use a 34901A to completely verify and adjust the internal DMM, make the following connections:

Calibration Procedures 4

Keysight 34970A/34972A Service Guide 69

4 Calibration Procedures

NOTE

Use shielded twisted pair PTFE insulated cables to reduce settling and noise errors. Connect the shield to the source LO output.

You can also use a 34902A for test and adjustment of voltage, frequency, and resistance functions. You cannot test or adjust current inputs with a 34902A. If you use a 34902A, connect the copper shorts to Channels 7 and 15 and make the input connections to Channels 8 and 16.

70 Keysight 34970A/34972A Service Guide

Calibration Security

NOTE

This feature allows you to enter a security code to prevent accidental or unauthorized adjustments of the instrument. When you first receive your instrument, it is secured. Before you can adjust the instrument, you must unsecure it by entering the correct security code. See page 52 in Chapter 3 for a

procedure to enter the security code.

– The security code is set to “HP034970” or “AT034972”, depending on the

product number, when the instrument is shipped from the factory. The security

code is stored in non-volatile memory, and does not change when power has

been off, after a Factory Reset (*RST command), or after an Instrument Preset

(SYSTem:PRESet command).

– The security code may contain up to 12 alphanumeric characters. The first

character must be a letter, but the remaining characters can be letters,

numbers, or an underscore ( _ ). You do not have to use all 12 characters but

the first character must always be a letter.

If you forget your security code, you can disable the security feature by adding a jumper inside the instrument as described on the following page.

Calibration Procedures 4

Keysight 34970A/34972A Service Guide 71

4 Calibration Procedures

WARNING

To Unsecure the Instrument Without the Security Code

To unsecure the instrument without the correct security code, follow the steps below. A front panel procedure to unsecure the instrument is given on page 52.

See “Electrostatic Discharge (ESD) Precautions” on page 6 before beginning this procedure.

SHOCK HAZARD. Only service-trained personnel who are aware of the hazards involved should remove the instrument covers. The procedures in this section require that you connect the power cord to the instrument with the covers removed. To avoid electrical shock and personal injury, be careful not to touch the power-line connections.

1 Disconnect the power cord and all input connections.

2 Remove the instrument cover (see page 16). Turn the instrument over.

3 Apply power and turn on the instrument.

Be careful not to touch the power line connections.

– Exposed Mains

–Do not Touch!

72 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

Apply Short

4 Apply a short between the two exposed metal pads marked

CAL UNLOCK as shown in the figure below.

5 While maintaining the short, enter any unsecure code. The instrument is now

unsecured.

6 Remove the short.

7 Turn off the instrument and remove the power cord. Reassemble the

instrument.

Now you can enter a new security code. Be sure to remember the new security

code.

Keysight 34970A/34972A Service Guide 73

4 Calibration Procedures

Calibration Message

The instrument allows you to store one message in calibration memory. For example, you can store such information as the date when the last calibration was performed, the date when the next calibration is due, the instrument’s serial number, or even the name and phone number of the person to contact for a new calibration.

– You can record a calibration message only from the remote interface and only

when the instrument is unsecured. You can read the message from either the front-panel or over the remote interface. You can read the calibration message whether the instrument is secured or unsecured.

– The calibration message may contain up to 40 characters. From the front

panel, you can view 13 characters of the message at a time. Press to scroll

through the text of the message. Press again to increase the scrolling speed.

Calibration Count

You can query the instrument to determine how many calibrations have been performed. Note that your instrument was calibrated before it left the factory. When you receive your instrument, be sure to read the count to determine its initial value.

– The calibration count increments up to a maximum of 65,535 after which it

rolls over to “0”. Since the value increments by one for each calibration point, a complete calibration may increase the value by many counts.

– The calibration count is also incremented with calibrations of the DAC

channels on the multifunction module.

– Front-Panel Operation:

– Remote Interface Operation:

CALibration:COUNt?

74 Keysight 34970A/34972A Service Guide

CAL COUNT

Calibration Procedure

CAUTION

The following procedure is the recommended method to complete an instrument calibration.

1 Read Test Considerations (page 14).

2 Unsecure the instrument for calibration (page 52).

3 Perform the verification tests to characterize the instrument (incoming data).

4 Perform the zero adjustment procedures.

5 Perform the gain adjustment procedures. Perform the verification tests to

verify the adjustments (outgoing data).

6 Secure the instrument against calibration.

7 Note the new security code and calibration count in the instrument’s

maintenance records.

Aborting a Calibration in Progress

Calibration Procedures 4

Sometimes it may be necessary to abort a calibration after the procedure has already been initiated. You can abort a calibration at any time by turning off the power. When performing a calibration from the remote interface, you can abort a calibration by issuing a remote interface device clear message.

If you abort a calibration in progress when the instrument is attempting to write new calibration constants to EEPROM, you may lose all calibration constants for the function. Typically, upon re-applying power, the instrument will report error 705 Cal:Aborted. You may also generate errors 740 through

746. If this occurs, you should not use the instrument until a complete re-adjustment has been performed.

Keysight 34970A/34972A Service Guide 75

4 Calibration Procedures

Test Considerations

To ensure proper instrument operation, verify that you have selected the correct power line voltage prior to attempting any procedure in this chapter. See “If the

Instrument Does Not Turn On” on page 41.

Errors may be induced by AC signals present on the input leads during a self-test. Long test leads can also act as an antenna causing pick-up of AC signals.

For optimum performance, all procedures should comply with the following recommendations:

– Assure that the calibration ambient temperature is stable and between 18 °C

and 28 °C. Ideally the calibration should be performed at 23 °C ±1 °C.

– Assure ambient relative humidity is less than 80%.

– Allow a 2-hour warm-up period with a copper short connected and the

multiplexer module installed before verification or adjustment.The connections are shown in the figure on page 7.

– Use shielded twisted pair PTFE insulated cables to reduce settling and noise

errors. Keep the input cables as short as possible.

– Connect the input cable shield to the source LO output.Except where noted in

the procedures, connect the calibrator LO source to earth ground.

Two-wire Ohms measurements are affected by the entire path length, including the plug-in card trace length and slot trace lengths. On the 34901A, Channel 10 is recommended as the median path length (on the 34902A, use Channel 8) for 2-wire Ohms verification and adjustments. Install the input multiplexer in slot 200.

Because the instrument is capable of making highly accurate measurements, you must take special care to ensure that the calibration standards and test procedures used do not introduce additional errors. Ideally, the standards used to verify and adjust the instrument should be an order of magnitude more accurate than each instrument range full scale error specification.

For the DC voltage, DC current, and resistance gain verification measurements, you should take care to ensure the calibrator’s “0” output is correct. If necessary, the measurements can be referenced to the calibrator’s “0” output using Mx + B scaling (see page 57). You will need to set the offset for each range of the measuring function being verified.

76 Keysight 34970A/34972A Service Guide

Performance Verification Tests

Use the Performance verification Tests to verify the measurement performance of the instrument. The performance verification tests use the instrument’s specifications listed in Chapter 1, "Specifications" starting on page 29.

You can perform four different levels of performance verification tests:

Self-Test

A series of internal verification tests that give a high confidence that the instrument is operational.

Quick Verification

A combination of the internal self-tests and selected verification tests.

Performance Verification Tests

An extensive set of tests that are recommended as an acceptance test when you first receive the instrument or after performing adjustments.

Optional Verification Tests

Calibration Procedures 4

Tests not performed with every calibration. Perform these tests to verify additional specifications or functions of the instrument.

Keysight 34970A/34972A Service Guide 77

4 Calibration Procedures

Self-Test

A brief power-on self-test occurs automatically whenever you turn on the instrument. This limited test assures that the instrument is capable of operation and also checks the plug-in cards for basic operation.

To perform a complete self-test hold down the

switch to turn on the instrument; hold down the seconds until the instrument beeps (a complete description of these tests can be

found in Chapter 6). The instrument will automatically perform the complete self-test procedure when you release the key. The self-test will complete in approximately 20 seconds.

– If the self-test is successful, “PASS” is displayed on the front panel.

– If the self-test fails, “FAIL” is displayed and the ERROR annunciator turns on. If

repair is required, see Chapter 6, "Service" for further details.

– If all tests pass, you have a high confidence (~90%) that the instrument is

operational.

key as you press the power

key for more than 5

78 Keysight 34970A/34972A Service Guide

Quick Performance Check

The quick performance check is a combination of internal self-test and an abbreviated performance test (specified by the letter Q in the performance verification tests). This test provides a simple method to achieve high confidence in the instrument’s ability to functionally operate and meet specifications. These tests represent the absolute minimum set of performance checks recommended following any service activity. Auditing the instrument’s performance for the quick check points (designated by a Q) verifies performance for “normal” accuracy drift mechanisms. This test does not check for abnormal component failures.

To perform the quick performance check, do the following:

– Perform a complete self-test. A procedure is given on page 16.

– Perform only the performance verification tests indicated with the letter Q.

If the instrument fails the quick performance check, adjustment or repair is required.

Performance Verification Tests

The performance verification tests are recommended as acceptance tests when you first receive the instrument. The acceptance test results should be compared against the 90 day test limits. You should use the 24-hour test limits only for verification within 24 hours after performing the adjustment procedure. After acceptance, you should repeat the performance verification tests at every calibration interval.

If the instrument fails performance verification, adjustment or repair is required.

Adjustment is recommended at every calibration interval. If adjustment is not made, you must guard band, using no more than 80% of the specifications listed in Chapter 1, as the verification limits.

Calibration Procedures 4

Keysight 34970A/34972A Service Guide 79

4 Calibration Procedures

Internal DMM Verification Tests

These procedures use inputs connected to a 34901A 20-Channel Multiplexer (see page 7) installed in slot 200.

Zero Offset Verification

This procedure is used to check the zero offset performance of the internal DMM. Verification checks are only performed for those functions and ranges with unique offset calibration constants. Measurements are checked for each function and range as described in the procedure below.

Zero Offset Verification Procedure

1 Make sure you have read “Test Considerations” on page 14.

2 This procedure will measure the shorts installed on Channels 209 and 219.

Leave the Amps input connections (Channel 221) open.

3 Select each function and range in the order shown in the table below. Before

executing each test, you must press to enable reading monitoring on the selected channel (or use the ROUTe:MON command from the remote interface).

Compare measurement results to the appropriate test limits shown in the table (see page 17).

Input

Open Open Open

Channel 221

Function

DC Current

Quick

[b]

Range 24 hour 90 day 1 year

10 mA

100 mA

Check

[a]

± 60 mA

± 1 mA ± 4 mA

Error from Nominal

± 2 mA ± 5 mA

± 100 mA

± 2 mA ± 5 mA

± 100 mA

80 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

NOTE

Input

Short Short Short Short Short

Short Short Short Short Short Short Short

[a] Q: Quick performance verification test points.

[b] Select 6½ digit resolution.

[c] For 2-wire ohms, an additional 4W of error must be added.

Function

DC Volts

2-Wire

Ohms

and

4-Wire

Ohms

[b]

Range 24 hour 90 day 1 year

100 mV

10V 100V 300V

100 W

1 kW

[c]

10 kW

100 kW

1 MW

10 MW

100 MW

Channel 209

Quick

Check

[a]

± 3.5 mV

± 40 mV

± 600 mV

± 3.5 mW

± 50 mW

± 500 mW

± 100 W

± 10 kW

± 6 mV

± 6 mW

± 10 W

Error from Nominal

± 4 mV ± 7 mV

± 50 mV

± 600 mV

± 9 mV

± 4 mW

± 10 mW

± 100 mW

± 1 W

± 10 W

± 100 W

± 10 kW

± 4 mV ± 7 mV

± 50 mV

± 600 mV

± 9 mV

± 4 mW

± 10 mW

± 100 mW

± 1 W

± 10 W

± 100 W

± 10 kW

Zero offset calibration using a mul tifunction calibrator is NOT recommended. The calibrator and cabling offset can be large and unstable causing poor offset calibration of the internal DMM.

Keysight 34970A/34972A Service Guide 81

4 Calibration Procedures

Gain Verification

This procedure is used to check the “full scale” reading accuracy of the internal DMM. Verification checks are performed only for those functions and ranges with unique gain calibration constants. Begin verification by selecting a measuring function and range. Make sure you have read “Test Considerations” on page 14.

DC VOLTS, Resistance, and DC CURRENT Gain Verification Test

1 Make sure you have read “Test Considerations” on page 14.

2 Select each function and range in the order shown below. Before executing

each test, you must press to enable reading monitoring on the selected channel (or use the ROUTe:MON command from the remote interface).

3 Compare measurement results to the appropriate test limits shown in the

table. (Be certain to allow for appropriate source settling.)

Input

-10 V

100 mV

10V 100V 300V

100 W

1 kW

10 kW

100 kW

1 MW

10 MW

100 MW

[c]

Channel 210

Function

DC Volts

2-Wire

Ohms

and

4-Wire

Ohms

± 30 W

Error from Nominal

± 250 mV

± 8 mV

± 37 mV ± 250 mV ± 4.1 mV

± 19.5 mV

± 12 mW ± 90 mW

± 900 mW

± 9 W

± 90 W

± 2.1 kW

± 810 kW

± 400 mV

± 9 mV

± 47 mV ± 400 mV ± 5.1 mV

± 22.5 mV

± 14 mW

± 110 mW

± 1.1 W

± 11 W ± 110 W ± 4.1 kW

± 810 kW

Quick

[b]

Range 24 hour 90 day 1 year

10V

100 mV

10V 100V 300V

100 W

1 kW

[d]

10 kW

100 kW

1 MW

10 MW

100 MW

Check

Q Q

[a]

± 190 mV

± 6.5 mV

± 26 mV

± 190 mV

± 2.6 mV

± 12 mV

± 6.5 mW

± 26 mW

± 250 mW

± 2.5 W

± 1.6 kW ±310 kW

82 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

Input

10 mA

100 mA

1 A

[a] Q: Quick performance verification test points.

[b] Select 6½ digit resolution.

[c] Verify only, no adjustment required.

[d] The 2-wire ohms resistance verification test is optional (see note on page 27). For 2-wire ohms, an additional 1 W

of error must be added (see page 29). Add a 1-second channel delay when using Fluke 5700 in 2-wire compensated mode. This avoids response time issues with 2-wire compensation when 34970A/34972A’s current source contains a pulse.

Function

DC Current

[b]

Range 24 hour 90 day 1 year

10 mA

100 mA

Channel 209

Quick

Check

[a]

± 1.5 mA

± 14 mA

± 560 mA

Error from Nominal

± 5 mA

± 35 mA

± 900 mA

± 7 mA

± 55 mA

± 1.1 mA

Keysight 34970A/34972A Service Guide 83

4 Calibration Procedures

AC VOLTS Gain Verification Test

Configuration: AC Volts LF 3 HZ:SLOW (in the Advanced menu)

1 Make sure you have read “Test Considerations” on page 14.

2 Select Channel 210, set the AC VOLTS function and the 3 Hz input filter. With

the slow filter selected, each measurement takes 7 seconds to complete.

Before executing each test, you must press to enable reading monitoring on the selected channel (or use the ROUTe:MON command from the remote

interface).

3 Select each range in the order shown below. Compare measurement results to

the appropriate test limits shown in the table. (Be certain to allow for appropriate source settling.)

Input

V rms Frequency 24 hour 90 day 1 year

100 mV 100 mV

1 V

1 V 10 V 10 V 10 V

[b]

10 mV

100 V 100 V 300 V

[c]

300 V

[a] Q: Quick performance verification test points.

[b] For this test, isolate the calibrator’s output from earth ground.

[c] Some calibrators may have difficulty driving the internal DMM and cable load at this V-Hz output. Use short, low

capacitance cable to reduce calibration loading. Verification can be performed at >195 Vrms. New test limits can be computed from the accuracy specification shown in Chapter 1 for the actual test conditions used.

1 kHz

50 kHz

1 kHz

50 kHz

1 kHz

50 kHz

10 Hz 1 kHz 1 kHz

50 kHz

1 kHz

50 kHz

Range

100 mV

1 V

10 V

100 mV

100 V

300V

Quick

Check

[a]

± 70 mV ± 150 mV ± 700 mV

± 1.5 mV

± 15 mV

± 34 mV

± 70 mV ± 150 mV ± 270 mV ± 600 mV

± 7 mV

Error from Nominal

± 90 mV ± 160 mV ± 900 mV ± 1.6 mV

± 9 mV

± 16 mV

± 9 mV ± 45 mV ± 90 mV

± 160 mV ± 390 mV ± 690 mV

± 100 mV ± 170 mV

± 1 mV

± 1.7 mV

± 10 mV ± 17 mV ± 10 mV

± 46 mV ± 100 mV ± 170 mV ± 420 mV ± 720 mV

84 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

NOTE

The 50 kHz AC voltage test points may fail performance verification if the internal shields have been removed and reinstalled. See “Gain Adjustment” on page 27, for further information on how to recalibrate the AC voltage function.

AC CURRENT Gain Verification Test

Configuration: AC Current LF 3 HZ:SLOW (in the Advanced menu)

1 Make sure you have read “Test Considerations” on page 14.

2 Select Channel 221, set the AC CURRENT function and the 3 Hz input filter.

With the slow filter selected, each measurement takes 7 seconds to complete. Before executing each test, you must press to enable reading monitoring

on the selected channel (or use the ROUTe:MON command from the remote interface).

3 Select each range in the order shown below. Compare measurement results to

the appropriate test limits shown in the table. (Be certain to allow for appropriate source settling.)

Input

Current Frequency 24 hour 90 day 1 year

[b]

10 mA

[b]

100 mA

10 mA

[b]

1 A

[a] Q: Quick performance verification test points.

[b] Verify only, no adjustment.

1 kHz 1 kHz 1 kHz 1 kHz

Range

10 mA

100 mA

1 A 1 A

Quick

Check

[a]

± 14 mA

± 600 mA

± 1.41 mA

± 1.4 mA

Error from Nominal

± 14 mA

± 600 mA

± 1.41 mA

± 1.4 mA

± 14 mA

± 600 mA

± 1.41 mA

± 1.4 mA

Keysight 34970A/34972A Service Guide 85

4 Calibration Procedures

Frequency Gain Verification Test

Configuration: Frequency 6½ digits

1 Make sure you have read “Test Considerations” on page 14.

2 Select Channel 210, select the FREQUENCY function and set 6½ digits.

3 Select each range in the order shown below. Compare measurement results to

the appropriate test limits shown in the table. (Be certain to allow for appropriate source settling.)

Input

Voltage Frequency 24 hour 90 day 1 year

[b]

10 mV

1 V

[a] Q: Quick performance verification test points.

[b] Verify only, no adjustment. For this test, isolate the calibrator’s output from earth ground.

100 Hz

100 kHz

Range

100 mV

1 V Q

Quick

Check

[a]

± 0.06 Hz

Error from Nominal

± 6 Hz

± 0.1 Hz

± 10 Hz

± 0.1 Hz

± 10 Hz

86 Keysight 34970A/34972A Service Guide

Optional AC Performance Verification Tests

These tests are not intended to be performed with every calibration. They are provided as an aid for verifying additional instrument specifications. There are no adjustments for these tests; they are provided for performance verification only.

Configuration: AC Volts LF 3 HZ:SLOW (in the Advanced menu)

1 Make sure you have read “Test Considerations” on page 14.

2 Select Channel 210, select the AC Volts function and the 3 HZ filter. Before

executing each test, you must press to enable reading monitoring on the selected channel (or use the ROUTe:MON command from the remote interface).

3 Select each range in the order shown below. Compare measurement results to

the appropriate test limits shown in the table. (Be certain to allow for appropriate source settling.)

Calibration Procedures 4

Input

Voltage Frequency 24 hour 90 day 1 year

1 V 1 V 1 V 1 V 1 V 1 V

10 V

1 V

100 mV

20 Hz

20 kHz 100 kHz 200 kHz 250 kHz 300 kHz

1 kHz 1 kHz 1 kHz

Range

1 V 1 V 1 V 1 V 1 V 1 V

10 V 10 V 10 V

± 700 mV ± 700 mV ± 6.3 mV

± 45 mV ± 45 mV ± 45 mV

± 7 mV

± 3.4 mV

± 13 mV

Error from Nominal

± 900 mV ± 900 mV

± 6.8 mV

± 45 mV ± 45 mV ± 45 mV

± 9 mV

± 4.5 mV

± 14 mV

± 1 mV ± 1 mV

± 6.8 mV

± 45 mV ± 45 mV ± 45 mV

± 10 mV

± 4.6 mV

± 14.06 mV

Keysight 34970A/34972A Service Guide 87

4 Calibration Procedures

NOTE

Internal DMM Adjustments

You will need a 34901A 20-Channel Multiplexer to perform the following procedures (see page 7). Install the Multiplexer in slot 200.

Zero Adjustment

Each time you perform a zero adjustment, the Internal DMM stores a new set of offset correction constants for every measurement function and range. The Internal DMM will sequence through all required functions and ranges automatically and store new zero offset calibration constants. All offset corrections are determined automatically. You may not correct a single range or

function without re-entering ALL zero offset correction constants automatically. This feature is intended to save calibration time and improve zero calibration consistency.

Never turn off the Internal DMM during Zero Adjustment.This may cause ALL calibration memory to be lost.

Zero Adjustment Procedure

The zero adjustment procedure takes about 5 minutes to complete. Be sure to allow the instrument to warm up for 2 hours before performing the adjustments.

Follow the steps outlined below. Review “Test Considerations” on page 14 before beginning this test. Also see page 56, for an example of how to initiate a zero calibration.

1 This procedure will use the copper shorts installed on Channels 209 and 219.

Leave the Amps input connections (Channel 221) open.

2 Select Channel 209. Select the DC VOLTS function.

3 Press

adjustment procedure.

4 Use the knob and arrow keys to set the number in the display to 0.000000 and

press .

5 Perform the Zero Offset Verification tests (see page 18) to check zero

calibration results.

88 Keysight 34970A/34972A Service Guide

to enter the calibration menu. Press

again to begin the

Gain Adjustment

NOTE

The Internal DMM stores a single new gain correction constant each time this procedure is followed. The gain constant is computed from the calibration value entered for the calibration command and from measurements made automatically during the adjustment procedure.

Most measuring functions and ranges have gain adjustment procedures. Only the 100 MW range does not have gain calibration procedures. The gain calibration value may be entered through the front panel menu or over the remote interface. See page 56, for an example of how to enter calibration values.

Adjustments for each function should be performed ONLY in the order shown in the performance verification table. See “Performance Verification Tests” earlier in this chapter for the tables used for gain adjustments.

Gain Adjustment Considerations

– The zero adjustment procedure must have been recently performed prior to

beginning any gain adjustment procedures.

– The optional –10 VDC adjustment should be performed only after servicing the

Internal DMM’s a-to-d converter or after replacing network A4U101 or calibration RAM A4U505.

Calibration Procedures 4

– When performing a 4-wire ohms gain adjustment, a new gain correction

constant is also stored for the corresponding 2-wire ohms measurement range. If desired, the 2-wire gain can be adjusted separately after the 4-wire ohms gain calibration is completed.

– During the AC voltage gain adjustments, some of the DC voltage gain

constants are used. Perform the DC voltage gain calibration before the AC voltage gain calibration.

Never turn off the instrument during a Gain Adjustment. This may cause calibration memory for the present function to be lost.

Keysight 34970A/34972A Service Guide 89

4 Calibration Procedures

Valid Gain Adjustment Input Values

Gain adjustment can be accomplished using the following input values.

Function Range Val id Cal ibration Input Values

DC VOLTS

100 mV to 100 V

300 V

0.9 to 1.1 x Full Scale 250 V to 303 V

OHMS, OHMS 4W

DC CURRENT

AC VOLTS

[a]

100W to 10 MW

10 mA to 1 A

10 mV to 100 V

300 V

AC CURRENT

Frequency

[a] Valid frequencies are as follows: 1 kHz ± 10% for the 1 kHz calibration,

45 kHz - 100 kHz for the 50 kHz calibration, and 10 Hz ± 10% for the 10 Hz calibration.

1 A

Any

0.9 to 1.1 x Full Scale

95 V to 303 V

9 mA to 11 mA

Any Input >100 mV rms,

1 kHz - 100 kHz

90 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

NOTE

Gain Adjustment Procedure

Adjustment for each function should be performed only in the order shown in the performance verification table. The performance verification tables used for gain adjustments start on page 20.

Review the Test Considerations (page 14) and Gain Adjustment (page 27) sections before beginning this test.

Configuration: DC functions — 6½ digits AC functions — LF 3 HZ:SLOW (in the Advanced menu)

1 Select Channel 210. Configure the channel to each function and range shown

in the gain verification tables (pages 18 – 79).

2 Apply the input signal shown in the “Input” column of the appropriate

verification table.

3 Note: Always complete tests in the same order as shown in the appropriate

verification table.

4 Press

to enter the calibration menu. Press

adjustment procedure.

5 Use the knob, and and to set the number in the display to the actual

input value and press .

again to begin the

6 Perform the appropriate Gain Verification Test to check the calibration results.

7 Repeat steps 1 through 6 for each gain verification test point shown in the

tables.

Each range in the gain adjustment procedure takes less than 20 seconds to complete.

Keysight 34970A/34972A Service Guide 91

4 Calibration Procedures

–10 VDC Adjustment Procedure (Optional)

The –10 VDC calibration electronically enhances the Internal DMM’s a-to-d converter linearity characteristic. This adjustment should ONLY be

performed after servicing the A-to-D converter or replacement of the calibration RAM.

You will need a 34901A 20-Channel Multiplexer to perform the following procedures (see page 7). Install the Multiplexer in slot 200.

1 If a zero calibration has not been performed recently, perform one before

beginning this procedure (see page 26).

2 Select Channel 210. Configure the channel as follows:

DC VOLTS

10 V range

6½ digits

INTEG 100 PLC (in the Advanced menu)

INPUT R > 10 G (in the Advanced menu)

Before executing each test, you must press to enable reading monitoring on the selected channel (or use the ROUTe:MON command from the remote

interface).

3 Measure and note the voltage offset present at the end of the measurement

cable by shorting the ends of the Channel 210 measurement cable. Be sure to use a copper wire and allow enough time for the residual thermal offset to stabilize (usually about 1 minute).

4 Connect the input cable to the calibrator output and set the calibrator to

output +10V. Allow enough settling time for any thermal offset voltages to stabilize (usually about 1 minute).

5 Perform a +10V DC gain calibration. Press

menu. Press

92 Keysight 34970A/34972A Service Guide

again to begin the adjustment procedure.

to enter the calibration

Calibration Procedures 4

6 Use the knob, and to set the number in the display to the sum of the

calibrator output and the measured offset (from step 3) and press . For example, if the calibrator output is 10.001 volts and the measured offset is 10

µV, enter +10.001010 volts. When the adjustment finishes, verify that new readings fall within ± 20 µV of the calibrator output plus the offset.

7 Reverse the cable connections to the calibrator to create a -10 VDC voltage

standard. You must physically reverse the cables. DO NOT switch the output polarity of the calibrator.

8 Perform a –10V DC gain calibration. Press

menu. Press

again to begin the adjustment procedure. Be sure to allow

to enter the calibration

time for thermal offsets to stabilize (usually about 1 minute).

9 Use the knob, and to set the number in the display to the difference of

the calibrator output and the measured offset (from step 3) and press . Using the previous example values, enter 10 µV minus 10.001 volts or

–10.000990 volts.

10 When the adjustment finishes, verify that new readings fall within ± 30 µV of

the calibrator output minus the offset.

Keysight 34970A/34972A Service Guide 93

4 Calibration Procedures

WARNING

Plug-in Module Test Considerations

For optimum performance, all test procedures should comply with the following recommendations:

– Assure that the calibration ambient temperature is stable and between 18 °C

and 28 °C. Ideally the calibration should be performed at 23 °C ± 1 °C.

– Assure ambient relative humidity is less than 80%.

– Install the plug-in module and allow a 45 minute warm-up period before

verification or adjustment.

– Use shielded twisted pair PTFE insulated cables to reduce settling and noise

errors. Keep the input cables as short as possible.

– Remove all user wiring and connections from the plug-in modules before

verification or adjustment.

– Use 4-wire Ohms measurement techniques for checking relay contact

resistance. Check directly at the terminals where possible.

TO PREVENT ELECTRICAL SHOCK

To prevent electrical shock, use only wire that is rated for the highest voltage to any channel. Before removing a module cover, turn off all power to external devices connected to the module.

CAUTION WITH MULTIPLE SIGNALS

To avoid the possibility of multiple signal sources becoming connected together, we recommend when multiplexing two or more sources they should be connected on separate modules or on separate banks of the same module.

94 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

WARNING

CAUTION WITH HAZARDOUS VOLTAGES

When any channel is connected to a hazardous voltage source, all channels in the module should be treated as hazardous and all channel wiring in the module should be rated for the maximum voltage applied. Thermocouples attached to any other channel on the module should have insulation rated for the maximum voltage, or have additional insulation added rated for the maximum voltage and should be isolated from conductive parts using a thermal compound or tape rated for the maximum voltage applied. Do not mount, move, or remove any thermocouples when the device under test is connected to a supply source.

ENVIRONMENTAL HEALTH AND SAFETY

When any channel is connected to a hazardous voltage source, the instrument and the device under test should be supervised, following local EHS practices to restrict access.

Keysight 34970A/34972A Service Guide 95

4 Calibration Procedures

Relay Verification

There are two methods you can use to verify relays:

– Read the relay cycle count.

– Measure the relay contact resistance.

Relay Cycle Count

– In addition to the channel relays, you can also query the count on backplane

relays and bank relays. Note that you cannot control the state of these relays from the front panel but you can query the count.

– You can also query the state of the three relays on the internal DMM. These

relays are numbered “1”, “2”, and “3” (which correspond to relays K102, K103, and K104 respectively). These relays open or close when a function or range is changed on a module.

– The 34908A multiplexer contains 40 channels which are switched (HI only)

using only 20 relays. Each relay is used to switch HI on two different channels (and only one channel can be closed at a time). The channels are arranged such that channels 01 and 21 use different contacts on the same relay. The remaining channels are also paired in the same manner (Channels 02 and 22, Channels 03 and 23, etc.). Therefore, when you query the relay count on a channel, the number reflects the number of times that the relay was closed. For example, the relay count will always be the same on Channels 01 and 21.

– You can reset the count (allowed only from remote) but the instrument must be

unsecured (see “To Unsecure for Calibration” on page 52 to unsecure the instrument).

– For more information on relay life and load considerations, refer to “Relay Life

and Preventative Maintenance” in Chapter 8 of the 34970A/34972A User’s Guide.

– A procedure to read the relay cycle count is given on page 58.

96 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

NOTE

(Optional) 34901A Relay Contact Resistance Verification

This optional procedure uses an external DMM to make 4-wire ohms measurements across the relay contacts on the 34901A. The measured resistance is the series resistance of the two relay contacts (both contacts are in the same relay).

Be sure to read “Plug-in Module Test Considerations” on page 32.

Tests 1 - 5:

See the diagram on page 36 for the required connections for each test (be sure to probe the components at the indicated location). For these measurements, the 34901A is not installed in the 34970A/34972A. Record the 4-wire ohms measurements from the external DMM in the table below.

The connections to the external DMM are different for each of Tests 1, 2, 4, and

5. Be sure to verify the connections shown in the table below for each of the four tests.

Test #

1 L401 J101, C14 L401 J101, C14 _____________ Ohms

2 L402 J101, C15 L402 J101, C15 _____________ Ohms

3 Add (Test 1 + Test 2) _____________ Ohms

4 F501 C21 I F501 C21 I _____________ Ohms

5 F502 C22 I F502 C22 I _____________ Ohms

Connect bare copper wires (approximately 3 cm in length) to the I terminals of Channels 21 and 22 as shown below. These wires will be used to make shorts across the channels in Tests 6 through 39.

Keysight 34970A/34972A Service Guide 97

External DMM Ohmmeter Connections

Measured Value

HI LO HI Sense LO Sense

4 Calibration Procedures

Probe here for L402 measurement.

Probe here for F501 measurement. Probe here for F502 measurement.

Note: Be sure to probe the components at

the indicated locations on the module.

Connections for 34901A Verification Tests 1 through 5

98 Keysight 34970A/34972A Service Guide

Calibration Procedures 4

Channel 20 should be left open.

Tests 6 - 8:

Make the connections to the 34901A as shown in the diagram below. Be sure to route your wiring for proper strain relief and install the module cover. Install the 34901A in slot 200 of the 34970A/34972A. Open all channels on the module by

performing a Factory Reset (press again and select “Factory Reset”). Configure Channel 20 as follows: DC volts, 10

volt range, and 5½ digits.

and select “Recall State”; press

Connections for 34901A Verification Tests 6 through 39

Keysight 34970A/34972A Service Guide 99

4 Calibration Procedures

Enable reading monitoring by pressing on the selected channel (or use the ROUTe:MON command). Record the 4-wire ohms measurements from the external

DMM in the following table.

Test #

6 Ch 20 P2 P2 P1 P1 ________Ohms 2.00 W K421

7 Ch 20 P2 P2 P3 P3 ________Ohms — —

8 Subtract (Test 7 - Test 6) ________Ohms 2.00 W K422

Channel

Configured

External DMM Ohmmeter Connections

HI LO HI Sense LO Sense

Measured Value

Test

Limit

Relay Measured

Tests 9 - 10:

Open all channels on the module by performing a Factory Reset. Configure Channel 10 (module in slot 200) as follows: 4-wire ohms, 1 kW range, and 5½ digits.

Enable reading monitoring by pressing on the selected channel (or use the ROUTe:MON command). Record the 4-wire ohms measurements from the external

DMM in the following table.

Test #

9 Ch 10 P2 P2 P3 P3 ________Ohms — —

10 Subtract (Test 9 - Test 3) ________Ohms 2.00 W K423

Channel

Configured

External DMM Ohmmeter Connections

HI LO HI Sense LO Sense

Measured Value

Test

Limit

Relay Measured

100 Keysight 34970A/34972A Service Guide

Used Agilent Agilent Used 34970A Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Software Updates/Licenses

Safety Symbols

Safety Considerations

General

Before Applying Power

Ground the Instrument

Do Not Operate in an Explosive Atmosphere

Do Not Remove the Instrument Cover

Do Not Modify the Instrument

In Case of Damage

Environmental Conditions

Regulatory Markings

Waste Electrical and Electronic Equipment (WEEE) Directive

Product category

The Front Panel at a Glance

The Front-Panel Menu at a Glance

Display Annunciators

The 34970A Rear Panel at a Glance

The 34972A Rear Panel at a Glance

For serial number MY59000100 & SG59000100 and below.

For serial number MY59000101 & SG59000101 and above.

The Plug-In Modules at a Glance

In This Book

Table of Contents

1 Specifications

2 Quick Start

Quick Start

To Prepare the Instrument for Use

To Connect Wiring to a Module

To Set the Time and Date

To Configure a Measurement Channel

To Monitor a Single Channel

To Close a Channel

If the Instrument Does Not Turn On

To Adjust the Carrying Handle

To Rack Mount the Instrument

3 Front-Panel Overview

Front-Panel Overview

Front-Panel Menu Reference

To Unsecure for Calibration

To Secure Against Calibration

To Change the Security Code

Error Messages

To Perform a Zero Adjustment

To Apply Mx+B Scaling to Measurements

To Read the Relay Cycle Count

To Read a Digital Input Port

To Write to a Digital Output Port

To Read the Totalizer Count

To Output a DC Voltage

4 Calibration Procedures

Calibration Procedures

Keysight Technologies Calibration Services

Calibration Interval

Adjustment is Recommended

Time Required for Calibration

Automating Calibration Procedures

Recommended Test Equipment

Input Connections

Calibration Security

To Unsecure the Instrument Without the Security Code

Calibration Message

Calibration Count

Calibration Procedure

Aborting a Calibration in Progress

Test Considerations

Performance Verification Tests

Self-Test

Quick Performance Check

Performance Verification Tests

Internal DMM Verification Tests

Zero Offset Verification

Gain Verification

Optional AC Performance Verification Tests

Internal DMM Adjustments

Zero Adjustment