Agilent E1312A Users Guide

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Contents

HP E1312A and HP E1 412A 6 1/2 Digit Multimeter User’s Manual

Edition 3

Warranty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

WARNINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Safety Symb ols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Declaration of Conformity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Reader Comment Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1. HP E1312A and HP E1412A Multimeter Module Setup . . . . . . . . . . . . . . . . . . 12

General Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Setting the Module Address Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Setting the Line Frequency Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Checking the Line Frequency Reference . . . . . . . . . . . . . . . . . . . . . . . . . 14

Initial Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2. HP E1312A/E1412A Multimeter Application Information . . . . . . . . . . . . . . . . . 22

Thermal EMF Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Loading Errors (dc volts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Leakage Current Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Rejecting Power Line Noi se Voltages . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Common Mode Rejection (CMR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Noise Caused by Magnetic Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Noise Caused by Ground Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

4-Wire Ohms Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Removing Field Wiring Resistance Errors

in 2-Wire Ohms Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Power Dissipation Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Settling Time Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

Errors in High Resistance Measurements . . . . . . . . . . . . . . . . . . . . . . . . . 28

Making High-Speed DC and Resistance Measurements . . . . . . . . . . . . . . . . . 29

Crest Factor Errors (non-sinusoidal inputs) . . . . . . . . . . . . . . . . . . . . . . . . 31

Loading Errors (ac volts) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

AC Measurements Below Full Scale . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Function and Range Change Internal Offset Correction . . . . . . . . . . . . . . . . . 32

Low-Level Measurement Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

AC Turnover Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

AC Signal Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

DC Input Re sistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Integration Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Autozero . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual Contents 1

Ranging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

AVERage Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

NULL (Rela tive) Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

dB Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

dBm Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

LIMit Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

The Trigger Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

External Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Internal Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Bus Triggering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

The Wait-for-Trigger State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

The Trigger Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Checking the Trigger Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Inserting a Trigger Delay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Default Delays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Querying the Delay Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

The Sample Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Checking the Sample Count . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

HP VTL Software (VISA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Example Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Making Multimeter Measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Synchronizing the Multimeter With a Switch Module . . . . . . . . . . . . . . . . . . 56

Multimeter Status System Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

HP VEE Programming Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

3. Multimeter Command Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Command Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Common Command Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

SCPI Command Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Linking Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Multimeter Range and Resolution Tables . . . . . . . . . . . . . . . . . . . . . . . . . 69

SCPI Comman d Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

IEEE 488.2 Common Command Quick Reference . . . . . . . . . . . . . . . . . . . 161

SCPI Command Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166

A. HP E1312A and HP E1412A Mul timeter Specific ations . . . . . . . . . . . . . . . . . . 170

Measuring Chracteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171

Operating Characteristics

Measuring Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

To Calculate Total Measurement Error . . . . . . . . . . . . . . . . . . . . . . . . . . 179

Understan d ing the “% of reading” Error . . . . . . . . . . . . . . . . . . . . . . . . . 179

Understanding the “% of range” Error . . . . . . . . . . . . . . . . . . . . . . . . . . 180

Interpreting Multimeter Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Number of Digits and Overrange . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

[8] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172

2 Contents HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual

Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181

Transfer Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

24-Hour Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

90-Day and 1-Year Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Temperature Coefficients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182

Configuring for Highest Accuracy Measurements . . . . . . . . . . . . . . . . . . . . 183

B. HP E1312A and HP E1412A Multimete r Error Messages . . . . . . . . . . . . . . . . . 184

C. Measurement Speed and Accuracy Tradeoffs . . . . . . . . . . . . . . . . . . . . . . . . 194

Speed Advantage Using the Special Non-SCPI Commands (F1-F4 and R1-R7) . . . . 195

Resolution Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196

Avoid Function Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

Avoid Aperture Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197

Minimize the Number of Command / Response Sessions . . . . . . . . . . . . . . . . 197

Set Autozeroing to ONCE or OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

Turn Auto Ranging OFF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 198

Decrease Aperture Time or NPLCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Store the Readings in Multimeter RAM Instead of Sending them Directly to the

Computer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual Contents 3

Notes

4 Contents HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual

Certification

Hewlett-Packard Company certifies that this product met its published specifications at the time of shipment from the factory. HewlettPackard further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology (formerly National Bureau of Standards), to the extent allowed by that organization’s calibration facility, and to the calibration

facilities of other International Standards Organization members.

Warranty

This Hewlett-Packard product is warranted against defects in materials and workmanship for a period of three years from date of shipment. Duration and conditions of warranty for this product may be superseded when the product is integrated into (becomes a part of) other HP products. During the warranty period, Hewlett-Packard Company will, at its option, either repair or replace products which prove to be defective.

For warranty service or repair, this product must be returned to a service facility designated by Hewlett-Packard (HP). Buyer shall prepay shipping charges to HP and HP shall pay shipping charges to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to HP from another country.

HP warrants that its software and firmware designated by HP for use with a product will execute its programming instructions when properly installed on that produ c t. HP do e s not war ra n t th a t th e ope ra tion of the product , or s oftware, or firmwa r e w ill be uninterrupte d or error free.

Limitation Of Warranty

The foregoing wa rr a nt y s ha l l not apply to defects resulting from im p r op e r or ina d e qu a te m a in te n a nc e by Buye r , Buye r -s u pp l i e d products or interfacing, unauthorized modification or misuse, operation outside of the environmental specifications for the product, or improper site preparation or maintenance.

The design and implement ation of any circuit on this product is th e sole respo nsi bi li ty of the Buyer. HP does not warrant the Buyer’s

circuitry or m a lfu nc tions of HP products th a t r e s ul t f rom th e Bu yer ’s c ir c u itry. In addition, HP doe s not warrant any dam a g e that occurs as a result of the Buyer’s circuit or any defects that result from Buyer-supplied products.

NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HP SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

Exclusive Remedies

THE REMEDIES PROVIDED HEREIN ARE BUYER’S SOLE AND EXCLUSIVE REMEDIES. HP SHALL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER LEGAL THEORY.

Notice

The information contained in this document is subject to change without notice. HEWLETT-PACKARD (HP) MAKES NO WARRANTY OF ANY KIND WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. HP shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing , performance or use of this material. This document contains proprietary information which is protected by copyright. All rights are reserved. No part of this document may be photocopied, reproduced, or translated to another language witho ut the prior written consent of Hewlett-Packard Company. HP assumes no responsibility for the use or reliability of it s software on equipment that is not f urnished by HP.

Restricted Rights Legend

Use, duplication or disclosure by the U.S. Government is subject to restrictions as set forth in subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause in DFARS 252.227-7013.

Hewlett-Packard Company 3000 Hanover Street Palo Alto, California 94304 U.S.A.

Rights for U.S. Government Departments and Agencies not part of the Department of Defense (DOD) are as set forth in FAR 52.22719 (c) (1,2).

HP E1312A and HP E1 41 2A 6 1/ 2 D igit Multime te r U s e r’ s M anual and SCPI Progra m m i ng Gu id e

Edition 3

5 HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide

Documentation History

All editions and updates of this manual and their creation date are listed below. The first edition of the manual is Edition 1. The edition number increments by 1 whenever the manual is revised. Updates, which are issued between editions, contain replacement pages to correct or add additional information to the current edition of the manual. Whenever a new edition is created, it will contain all of the update information for the previous edition. Each new edition or update also includes a revised copy of this documentation history page.

Edition 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . August 1995

Edition 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . January 1996

Edition 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . June 1996

Safety Symbols

Instructio n m a nu a l s ym b ol affixed to pro duct. Indicates that the user must refer to the manual for specific WARNING or CAUTION information to avoid personal injury or damage to th e product.

Indicates the field wiring terminal that must be connected to earth ground before operating the equipment—protects against electrical shock in case of fault.

Frame or chassis ground terminal—typically connects to the equipment’s metal frame.

WARNING

CAUTION

Alternating current (AC).

Direct current (DC).

Indicates hazardous voltages.

Calls attention to a procedure, practice, or condition that c ould cau se bodi l y in ju ry or death.

Calls attention to a procedure, practice, or condition that could possibly cause damage to equipment or pe r m a n e nt loss of data.

WARNINGS

The following general safety precautions must be observed during all phases of operation, service, and repair of this product. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the product. Hewlett-Packard Company assumes no liabil ity for the customer’s failure to

comply with these requirements. Ground the equipment: For Safety Class 1 equipment (equipment having a protective earth terminal), an uninterruptible safety earth

ground must be provid e d from th e mai ns po we r sourc e to the pro du c t in pu t w iring terminals or s up pl ie d powe r c a bl e .

DO NOT operate the product in an explosive atmosphere or in the presence of flammable gases or fumes.

For continued protection against fire, replace the line fuse(s) only with fuse(s) of the same voltage and current rating and type. DO NOT use repaired fuses or short-circuited fuse holders.

Keep away from live circuits: Operating personnel must not remove equipment covers or shields. Procedures involving the removal of covers or shields are for use by service-trained personnel only. Under certain conditions, dangerous voltages may exist even with the equipment switched off. To avoid dangerous electrical shock, DO NOT perform procedures involving cover or shield removal unless you are qualified to do so.

DO NOT operate damaged equipment: Whenever it is possible that the safety protection features built into this product have been impaired, either through physical damage, excessive moisture, or any other reason, REMOVE POWER and do not use the product until safe operation can be verified by service-trained personnel. If necessary, return the product to a Hewlett-Packard Sales and Service Office for service and repair to ensure that safety features are maintained.

DO NOT service or adjust alone: Do not attempt internal service or adjustment unless another person, capable of rendering first aid and resuscitation, is present.

DO NOT substitute parts or modify equipment: Because of the danger of introducing additional hazards, do not install substitute parts or perform any unauthorized modification to the product. Return the product to a Hewlett-Packard Sales and Service Office for service and repair to ensure that safety features are maintained.

HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide 6

Declaration of Conformity

according to ISO/IEC Guide 22 and EN 45014

Manufacturer’s Name: Hewlett-Packard Company

Loveland Manufacturing Center

Manufacturer’s Address: 815 14th Street S.W.

Loveland, Colorado 80537

declares, that the product:

Product Name: 6 1/2 Digit Multimeter Module

Model Number: E1312A

Product Options: All

conforms to the following Product Specifications:

Safety: IEC 1010-1 (1990) Incl. Amend 1 (1992)/EN61010-1 (1993)

CSA C22.2 #1010.1 (1992) UL 3111-1

EMC: CISPR 11:1990/EN55011 (1991): Group1 Class A

EN50082-1:1992

IEC 801-2:1991: 4kV CD, 8kV AD IEC 801-3:1984: 3 V/m IEC 801-4:1988: 1kV Power Line, 0.5kV Signal Lines

Supplementary Information: The product herewith complies with the requirements of the low voltage Directive 73/23/EEC and the EMC Directive 89/336/EEC and carries the "CE" marking accordingly.

Tested in a typical HP B-Size VXI mainframe.

Jim White, QA Manager

May 8, 1996

European contact: Your local Hewlett-Packard Sales and Service Office or Hewlett-Packard GmbH, Department

ZQ/Standards Europe, Herrenberger Straße 130, D-71034 Böblingen, Germany.

7 HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide

Declaration of Conformity

according to ISO/IEC Guide 22 and EN 45014

Manufacturer’s Name: Hewlett-Packard Company

Loveland Manufacturing Center

Manufacturer’s Address: 815 14th Street S.W.

Loveland, Colorado 80537

declares, that the product:

Product Name: 6 1/2 Digit Multimeter Module

Model Number: E1412A

Product Options: All

conforms to the following Product Specifications:

Safety: IEC 1010-1 (1990) Incl. Amend 1 (1992)/EN61010-1 (1993)

CSA C22.2 #1010.1 (1992) UL 3111-1

EMC: CISPR 11:1990/EN55011 (1991): Group1 Class A

EN50082-1:1992

IEC 801-2:1991: 4kV CD, 8kV AD IEC 801-3:1984: 3 V/m IEC 801-4:1988: 1kV Power Line, 0.5kV Signal Lines

Supplementary Information: The product herewith complies with the requirements of the low voltage Directive 73/23/EEC and the EMC Directive 89/336/EEC and carries the "CE" marking accordingly.

Tested in a typical HP C-Size VXI mainframe.

Jim White, QA Manager

July 31, 1995

European contact: Your local Hewlett-Packard Sales and Service Office or Hewlett-Packard GmbH, Department

ZQ/Standards Europe, Herrenberger Straße 130, D-71034 Böblingen, Germany.

HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide 8

NOTES

9 HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide

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Reader Comment Sheet

HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide

Edition 3

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11 HP E1312A and HP E1412A 6 1/2 Digit Multimeter User’s Manual and SCPI Programming Guide

Chapter 1

HP E1312A and HP E1412A Multimeter Module Setup

Using This Chapter This chapter provides one page of general module information followed by

the tasks you must perform to set up your module and verify your installation was successful. Chapter contents are:

• Setting the Module Address Switch

• Interrupt Priority

• Setting and Checking the Line Frequency Reference

• Input Terminals and Front Panel Indicators

• Multimeter Functional Connections

• Initial Operation

General Information • The HP E1312A (VXI B-size) and HP E1412A (VXI C-size) multimeters

are VXIbus mess ag e- ba se d sl a ve dev i ce s.

• Programming the multimeter can either be through a command module

using an HP-IB interface or an embedded controller. You use the Standard Commands for Programmable Instruments (SCPI; see Chapter

3) with the Standard Instrument Control Language (SICL) or VISA (Virtual Instrument Software Architecture).

• Maximum voltage is 300 V

• Maximum current is 3A AC

• Resolution is from 4 1/2 digits for fast measurements to 6 1/2 digits for

or 300 Vdc.

rms

or DC.

rms

more accuracy. Resolution is set by specifying the integration time in number of power line cycles (NPLCs) or corresponding aperture time. The following table shows th e co rr el a t ion between NPL Cs an d re solution.

Power Line Cycles Resolution

0.02 0.0001 x Full-Scale

0.2 0.00001 x Full-Scale 1 0.000003 x Full-Scale

10 0.000001 x Full-Scale

100 0.0000003 x Full-Scale

Chapter 1 HP E1312A and HP E1412A Multimeter Module Setup 12

Setting the Module Address Switch

The logical address switch factory setting is 24. Valid addresses are from 1 to 254 for static configuration (the address you set on the switch) and address 255 for dynamic configuration. The HP E1312A and HP E1412A support dynamic configuration of the address. This means the address is set programmatically by the resource manager when it encounters a module with address 255 that supports dynamic configuration.

If you install more than one multimeter, each module must have a different logical address. If you use a VXIbus command module, the logical address must be a multiple of eight (e.g., 32, 40, 48, etc.) Each instrument must have a unique secondary address which is the logical address divided by eight.

Note

When using an HP E1405A/B or E1406A as the VXIbus resource manager

with SCPI commands, the multimeter’s address switch value must be a multiple of 8.

Figure 1-1. Setting the Logical Address

13 HP E1312A and HP E 14 12 A M ul t i m et er M od ul e S et up Chapter 1

Interrupt Priority The HP E1312A and E1412A Multimeter are VXIbus interrupters. However,

there is no interrupt priority level setting to be made on the module. Interrupt priority level, setup and activation are configured on the resource manager which is the interface to the VXIbus and contains any instrument drivers required to communicate with a VXI module. Your resource manager could be a VXI command module, embedded PC controller, the PC-based VXLink Interface (ISA-to-VXI), the Series 700 workstation VXI-MXIbus interface or another VXI controller. To configure the interrupt priority on the HP E1405B and E1406A Command Modules, you would use the DIAGnostic :INTerrupt

command subsystem. Refer to your resource manager’s documentation for information on setting the system’s interrupt priority.

Setting the Line Frequency Reference

You must set the line frequency reference to the line frequency of the power source to your mainframe for maximum normal mode rejection (NMR). NMR is the multimeter’s ability to reject power line frequency noise in a DC voltage or ohms measurement. You should set the multimeter’s line frequency reference to the exact power line frequency (50, 60 or 400 Hz). Failure to set the line frequency reference to that of your source will cause reading errors.

Checking the Line

Frequency Reference

You use the CALibration:LFRequency command to set the line frequency reference. The default setting at power-on is 60 Hz. If you use 50 Hz or 400 Hz you need to set the line frequency reference for maximum NMR. Specifying 400 Hz actually sets the line frequency reference to 50 Hz since 50 Hz is a sub harmonic of 400 Hz. Executing a CALibration:LFRequency? will return "+50" after executing CAL:LFR 400 to set the line frequency reference to 400 Hz.

The line frequency reference setting is also useful when the device being measured operates at a different frequency than the multimeter. For example, if the multimeter has a power line frequency reference of 60 Hz and the device being measured has a power line frequency of 50 Hz, maximum NMR is achieved by setting the multimeter’s reference frequency to 50 Hz by executing:

CAL:LFR 50

The CALibration:LFRequency? command returns the present setting of the power line frequency reference. The command returns "+50" or "+60". For a setting of 400 Hz, "+50" is returned since 50 Hz is a sub harmonic of 400 Hz.

Chapter 1 HP E1312A and HP E1412A Multimeter Module Setup 14

Front Panel Indicator

"Failed" turns on momentarily during the multimeter’s power-on self-test. If the multimeter successfully establishes internal communication, the indicator turns off. If the multimeter fails to establish internal communication, the indicator remains on.

"Access" turns on only when the resource manager is communicating with the multimeter.

"Errors" turns on only when an error is present in the multimeter’s error queue.

The error can result from improperly executing a

command or the multimeter being unable to pass self-test or calibration. Use the SYST:ERR? command repeatedly to read and clear the error queue (or use *CLS to clear the error queue without reading the errors). A response of +0,"No error" indicates the error queue is empty. See Appendix B, HP E1312A and E1412A Multimeter Error Messages, for a list of all errors.

"Sample" turns on while the multimeter is sampling the input for a measurement. The "Sample" indicator typically will blink.

Input Terminals

The multimeter’s front panel contains terminals for connecting input signals, receiving external trigger signals and accessing the voltmeter complete pulse.

NOTE: The outer shells of the "Trig" and "VM Complete" BNC connectors are connected to chassis as is the knurled knob above the HI terminal.

NOTE The HP E1412A front panel layout is shown in this figure; HP E1312A front panel indicators and input terminal layout is dimensionally the same as this figure.

Figure 1-2. Multimeter Measurement Terminals.

15 HP E1312A and HP E 14 12 A M ul t i m et er M od ul e S et up Chapter 1

Use Banana Plugs to connect field wiring to the input terminals of the Multimeter.

Multimeter Functional Connections

Figure 1-3. Switch Module Analog Bus Connections

Figure 1-4. Voltage Measurement Connections

Chapter 1 HP E1312A and HP E1412A Multimeter Module Setup 16

CURRENT FUSE Check for blown current fuse if you are unable to make current me as ur e me nts . Replace fuse with: HP P/N 2110-0957 3.15A, 250V (Cooper Industries Inc. P/N GDA-3.15).

Figure 1-5. Voltage Ratio (Vdc) Measurement Connections

Figure 1-6. Current Measurement Connections

17 HP E1312A and HP E 14 12 A M ul t i m et er M od ul e S et up Chapter 1

Null the test cabl e resistance

METHOD A: Manually characterize the then input the following commands.

CONF:RES 100 CALC:FUNC NULL CALC:NULL:OFFS < CALC:STAT ON

METHOD B: Short the test cable en d under program control then automatically store the cable resistan ce offset with the following commands.

CONF:RES 100 CALC:FUNC NULL CALC:STAT ON READ? (store s the null offset value) Enter reading (will be 0 because the null offset is subtracted from itself)

cable resistance

cable_resistance

Figure 1-7. 2-Wire Ohms Measurement Connections

Measure the unknown resistance

Subsequent measurements will automatically subtract the cable resistance (null offset) from the measured valu e.

Figure 1-8. 4-Wire Ohms Measurement Connections

Chapter 1 HP E1312A and HP E1412A Multimeter Module Setup 18

Figure 1-9. Frequency or Period Measurement Connections

19 HP E1312A and HP E 14 12 A M ul t i m et er M od ul e S et up Chapter 1

Initial Operation To program the Multimeter using SCPI, you must select the interface address

and SCPI commands to be used. General information about using SCPI commands is presented at the beginning of Chapter 3. See the HP 75000 Series C Installation and Getting Started Guide for interface addressing.

Note

Programming the

Multimeter

This discussion applies only to SCPI (Standard Commands for Programmable Instruments) programming. The program is written using VISA (Virtual Instrument Software Architecture) function calls. VISA allows you to execute on VXIplug&play system frameworks that have the VISA I/O layer installed (visa.h include file).

Example: Perform a Self-Test of the Multimeter and Read the Result.

Programming the multimeter using Standard Commands for Programmable Instruments (SCPI) requires that you select the controller language (e.g., C, C++, Basic, etc.), interface address and SCPI commands to be used. See the "C-Size Installation and Getting Started Guide" (or equivalent) for interfacing, addressing an d co ntr ol le r i nf or mat i o n.

The following C program verifies communication between the controller, mainframe and multimeter. It resets the module (*RST), queries the identity of the module (*IDN?) and initiates a self-test of the multimeter.

#include <stdio.h> #include <visa.h>

/*** FUNCTION PROTOTYPE ***/ void err_handler (ViSession vi, ViStatus x);

void main(void) {

char buf[512] = {0};

#if defined(_BORLANDC_) && !defined(_WIN32_) _InitEasyWin(); #endif

ViStatus err; ViSession defaultR M ; ViSession dmm;

/* Open resource manager and multimeter sessions. */

viOpenDefaultRM (&defaultRM); viOpen(defaultRM, "GPIB-VXI0::9::24", VI_NULL, VI_NULL, &dmm);

Chapter 1 HP E1312A and HP E1412A Multimeter Module Setup 20

/* Set the timeout value to 10 seconds. */

viSetAttribute (dmm, VI_ATTR_TMO_VALUE, 10000);

/* Reset the module. */

err = viPrintf (dmm, "*RST/n");

if (err<VI_SUCCESS) err_handler (dmm, err);

/* Query the module identification. */

err = viPrintf(dmm, "*IDN?/n");

if (err<VI_SUCCESS) err_handler (dmm, err);

err = viScanf(dmm, "%t", buf);

if (err<VI_SUCCESS) err_handler (dmm, err);

printf ("Module ID = %s/n/n", buf);

/* Perform a module self-test. */

err = viPrintf (dmm, "*TST?/n");

if(err<VI_SUCCESS) err_handler (dmm, err);

err = viScanf (dmm, "%t", buf);

if (err<VI_SUCCESS) err_handler (dmm, err);

printf ("Self-test response = %s/n/n", buf);

/* Check for system errors. */

err = viPrintf (dmm, "SYST:ERR?/n");

if (err<VI_SUCCESS) err_handler (dmm, err);

err = viScanf (dmm, "%t", buf);

if (err<VI_SUCCESS) err_handler (dmm, err);

printf ("System error response = %s/n/n", buf);

} /* end of main */

/*** Error handling function ***/

void err_handler (ViSession dmm, ViStatus err) {

char buf[1024 ] = {0};

viStatusDesc (dmm, err, buf); printf ("ERROR = %s/n", buf); return;

}

21 HP E1312A and HP E 14 12 A M ul t i m et er M od ul e S et up Chapter 1

Chapter 2

HP E1312A/E1412A Multimeter Application Information

Using this Chapter This chapter provides multimeter application information in five parts.

• Measurement Tutorial.

• Measurement Configuration.

• Math Operations.

• T riggering the Multimeter.

• HP E1312A and HP E1412A Multimeter Application Examples.

Measurement Tutorial

The HP E1312A and E1412A are capable of making highly accurate measurements. In order to achieve the greatest accuracy, you must take the necessary steps to eliminate potential measurement errors. This section describes common errors found in measurements and gives suggestions to help you avoid these errors.

DC Voltage Measurements

Thermal EMF Errors Thermoelectric voltages are the most common source of error in low-level dc

voltage measurements. Thermoelectric voltages are generated when you make circuit connections using dissimilar metals at different temperatures. Each metal-to-metal junction forms a thermocouple, which generates a voltage proportional to the junction temperature. You should take the necessary precautions to minimize thermocouple voltages and temperature variations in low-level voltage measurements. The best connections are formed using copper-to-copper crimped connections. The table below shows common thermoelectric voltages for connections between dissimilar metals.

Copper-to-

Copper Gold Silver

Approx. µV/°C

<0.3

0.5

The HP E1312A and HP E1412A input terminals are copper alloy.

Brass Beryllium Copper Aluminum Kovar or Alloy 42 Silicon Copper-Oxide Cadmium-Tin Solder Tin-Lead Solder

3 5 5

500

1000

0.2 5

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 22

Loading Errors (dc

volts)

Measurement l oa d in g er ro rs o cc ur when the resistan ce of t he dev i ce under-test (

resistance. The diagram below shows this error source.

To reduce the effects of loading errors, and to minimize noise pickup, you can set the multimeter’s input resistance to greater than 10 GΩ for the 100 mVdc, 1 Vdc, and 10 Vdc ranges. The input resistance is maintained at 10 MΩ for

the 100 Vdc and 300 Vdc ranges.

DUT) is an appreciable percentage of the multimeter’s own input

Leakage Current

Errors

The multimeter’s input capacitance will “ charge up” due to input bias currents when the terminals are open-circuited (if the input resistance is

10 GΩ). The multimeter’s measuring circuitry exhibits approximately 30 pA of input bias current for ambient temperatures from 0°C to 30°C. Bias current

will double (×2) for every 8°C change in ambient temperature above 30°C. This current generates small voltage offsets dependent upon the source resistance of th e dev i ce -u nd er -t e st. T hi s effec t bec om e s ev i de nt fo r a source

resistance of greater than 100 kΩ, or when the multimeter’s operating temperature is significantly greater than 30°C.

23 HP E1312A/E1412A Multimeter Application InformationChapter 2

Rejecting Power Line

Noise Voltages

A desirable characteristic of integrating analog-to-digital (A/D) converters is their ability to reject spurious signals. The integrating techniques reject power-line related noise present with a dc signal on the input. This is called normal mode rejection or

NMR. Normal mode noise rejection is achieved

when the multimeter measures the average of the input by “integrating” it over a fixed period. If you set the integration time to a whole number of power line cycles (

PLCs) these errors (and their harmonics) will average out to

approximately zero.

The HP E1312A and E1412A provide three A/D integration times (1, 10 and 100 PLCs) to reject power line frequency noise (and power-line frequency harmonics). Power line frequency defaults to 60 Hz unless you specifically set it to 50 Hz with the CAL:LFR command. The multimeter determines the proper integration time based on which power line frequency is set. The table below shows the noise rejection achieved with various configurations. Select a longer integration time for better resolution and increased noise rejection.

Common Mode

Rejection (CMR)

Power Line

Cycles (PLCs)

0.02

0.2 1

100

400 µs (400 µs) 3 ms (3 ms)

16.7 ms (20 ms) 167 ms (200 ms)

1.67 sec (2 sec)

Integration Time

60 Hz (50Hz)

NMR

NONE NONE

60 dB 60 dB 60 dB

Ideally, a multimeter is completely isolated from earth-referenced circuits. However, there is finite resistance between the multimeter’s input LO terminal and earth ground as shown below. This can cause errors when measuring small voltages which are floating relative to earth ground.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 24

Noise Caused by

Magnetic Loops

If you are making measurements near magnetic fields, you should take the necessary precau t io n s to av oi d in du ci n g vo lt ag es in the m ea su rem en t conductors. You should be especially careful when working near conductors carrying large currents. Use twisted-pair connections to the multimeter to reduce the noise pickup loop area, or dress the input cables as close together as possible. Also, loose or vibrating input cables will induce error voltages. Make sure your input cables are tied down securely when operating near magnetic fields. Whenever possible, use magnetic shielding materials or physical separation to reduce problem magnetic field sources.

Noise Caused by

Ground Loops

When measuring voltages in circuits where the multimeter and the deviceunder-test are both referenced to a common earth ground but at different

points, a “ground loop” is formed. As shown below, any voltage difference between the two ground reference points (V through the m ea su re m en t leads. This cause s er ro rs suc h as noi s e an d of fs et voltage (usually power-line related), which are added to the measured voltage.

The best way to eliminate ground loops is to maintain the multimeter’s input isolation from earth; do not connect the input terminals to ground. If the multimeter must be earth-referenced, be sure to connect it, and the device-under-test, to the same common ground point. This will reduce or eliminate any voltage difference between the devices. Also make sure the multimeter and device-under-test are connected to the same electrical outlet whenever possible.

ground) causes a current to flow

25 HP E1312A/E1412A Multimeter Application InformationChapter 2

Resistance Measurements

The HP E1312A and HP E1412A offer two methods for measuring resistance: 2-wire and 4-wire ohms. For both methods, the test current flows from the input HI terminal and then through the resistor being measured. For 2-wire ohms, the voltage drop across the resistor being measured is sensed internal to the multimeter. Therefore, input cable resistance is also measured. For 4-wire

ohms, separate “sense” connections are required. Since no current flows in the HI-LO "Sense" terminal cables, the resistances in these cables do not give a measurement error.

The errors discussed previously for dc voltage measurements also apply to resistance measurements. Additional error sources unique to resistance measurements are discussed in the following sections.

4-Wire Ohms

Measurements

The 4-wire ohms method provides the most accurate way to measure small resistance s. Err or s du e t o t es t cable resistan ce s an d co nt a ct re sis t an ce s ar e reduced using this method. Four-wire ohms is often used in automated test applications where long cable lengths, numerous connections, or switches exist between the multimeter and the device-under-test. The recommended connections for 4-wire ohms measurements are shown below.

Removing Field Wiring

Resistance Errors

in 2-Wire Ohms

Measurements

Field wiring can cause an offset error in 2-wire resistance measurements. You can use the following procedure to minimize offset errors associated with field wiring resistance in 2-wire ohms measurements. You short the field wiring at the DUT location and measure the 2-wire lead resistance. This value is subtracted from subsequent DUT 2-wire ohms measurements. There are two ways to effectively null out the lead resistance. The first way is to characterize yo u r fie l d l ea d re si s tance by shortin g th e lea d s at th e D U T location and measure and record the lead resistance. Then enable the math operation and store the 2-wire lead measurement value using the CALCulate: NULL:OFFSet <value> command (CALC:STATE must be ON to do this).

See the next page for SCPI examples to store a NULL value.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 26

CONF:RES

Set to 2-wire ohms function

short the lead resistance at the DUT location

READ?

Measure the 2-wire ohms lead resistance

enter lead resistance value into computer

CALCulate:FUNCtion NULL CALCulate:STATe ON CALCulate:NULL:OFFSet <value>

Subsequent 2-wire ohms measurements will subtract the null offset value from the measurement thereby removing the lead resistance from the measurement.

The second way to store the 2-wire lead resistance as the NULL offset value is to let the multimeter automatically do this with the first measurement. The first measurement made after CALCulate function is set to NULL and the STATe is set to ON stores the measured value as the null offset.

Set math operation to NULL Turn math operation ON Store the NULL offset value

CONF:RES

Set to 2-wire ohms function

short the lead resistance at the DUT location

CALCulate:FUNCtion NULL CALCulate:STATe ON READ?

Measure the 2-wire ohms lead resistance

Set math operation to NULL Turn math operation ON

Enter lead resistance value into computer, the value is automatically

stored in the multimeter’s null offset register. Remove the short from the lead resistance at the DUT location and connect leads to your DUT.

READ?

Make a 2-wire ohms resistance measurement Enter lead resistance value into computer. The NULL value is subtracted from the measurement to more accurately provide the DUT resistance.

27 HP E1312A/E1412A Multimeter Application InformationChapter 2

Power Dissipation

Effects

When measuri n g re si s tor s de si g ne d fo r tem p er at u re me as urem e nt s (or ot he r resistive d ev ice s w i t h lar ge te m pe ra t ure coefficient s) , be awar e t ha t th e multimeter will dissipate some power in the device-under-test. If power

dissipation is a problem, you should select the multimeter’s next higher measurement range to reduce the errors to acceptable levels. The following table shows several exampl es .

DUT

Range Test Current

Power at Full Scale

100

1 k

10 k

100 k

1 M

10 M

Ω

1 mA 1 mA 1 mW

100 µA 100 µW

10 µA 10 µW

5 µA 25 µW

500 nA

100 µW

2.5 µW

Settling Time Effects Both the HP E1312A and HP E1412A have the ability to insert automatic

measurement settling delays with the TRIG:DEL command. These delays are adequate for resistance measurements with less than 200 pF of combined cable and device capacitance. This is particularly important if you are

measuring resis t an ce s ab ov e 10 0 kΩ . Settling due to RC time constant effects can be quite long. Some precision resistors and multi-function calibrators use

large parallel capacitors (1000 pF to 0.1 µF) with high resistor values to filter out noise currents injected by their internal circuitry. Non-ideal capacitances in cables and other devices may have much longer settling times than expected just by RC time constants due to dielectric absorption (soak) effects. Errors will be measured when settling after the initial connection and after a range change .

Errors in High

Resistance

Measurements

When you are measuring large resistances, significant errors can occur due to insulation resistance an d su rf ac e cl e an l i ne ss . Y ou sho u ld ta ke th e ne ce ss ar y precautions to maintain a “clean” high-resistance system. Test cables and fixtures are susceptible to leakage due to moisture absorption in insulating materials and “dirty” surface films. Nylon and PVC are relatively poor

insulators (10

ohms). Leakage from nylon or PVC insulators can easily contribute a

(10

ohms) when compared to PTFE Teflon insulators

0.1% error when mea su ring a 1 MΩ resistance in humid conditions.

Teflon is a registered trademark of E.I. duPont deNemours and Co.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 28

Making High-Speed DC

and Resistance

Measurements

The multimeter incorporates an automatic zero measurement procedure (autozero) to eliminate internal thermal measurement actually consists of a measurement of the input terminals followed by a measurement of the internal offset voltage. The internal offset voltage error is subtracted from the measurement for improved accuracy. This compensate s fo r of fs et vo l tage changes due t o t emperature. For ma xi mum reading speed, turn autozero off. This will more than double your reading speeds for dc voltage, resistance, and dc current functions. Autozero does not apply to other measurement functions.

EMF and bias curr en t err or s. E ac h

DC Current Measurement Errors

When you connect the multimeter in series with a test circuit to measure current, a measurement error is introduced. The error is caused by the

multimeter’s series burden voltage. A voltage is developed across the wiring resistance and current shunt resistance of the multimeter as shown below.

29 HP E1312A/E1412A Multimeter Application InformationChapter 2

True RMS AC Measurements

True RMS responding multimeters, like the HP E1312A and HP E1412A,

measure the “heating” potential of an applied signal. Unlike an “average responding” measurement, a true

RMS measurement can be used to determine

the power dis sipated in a resis t an ce , ev en b y no n- sinusoidal signals. The power is proportional to the square of the measured true

RMS voltage,

independent of waveshape. An average responding ac multimeter is calibrated to read the same as a true

RMS meter for sinewave inputs only. For other

waveform shapes, an average responding meter will exhibit substantial errors as shown below.

The multimeter’s ac voltage and ac current functions measure the ac-coupled

RMS value. This is in contrast to the ac+dc true RMS value shown above.

true Only the “heating value” of the ac components of the input waveform are measured (dc is rejected). For non-offset sinewaves, triangle waves, and square waves, the ac and ac+dc values are equal since these waveforms do not contain a dc offset. Non-symmetrical waveforms, such as pulse trains, contain dc voltages which are rejected by ac-coupled true

An ac-coupled tru e

RMS measurement is desirable in situations where you are

RMS measurements.

measuring small ac signals in the presence of large dc offsets such as when measuring ac ripple present on dc power supplies. There are situations, however, where you might want to know the ac+dc true

RMS value. You can

determine this value by combining results from dc and ac measurements as shown below. You should perform the dc measurement using at least 10 power line cycles of integration (6 digit mode) for best ac rejection.

RMS

(ac

= √ac2 + dc

dc)

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 30

Crest Factor Errors

(non-sinusoidal inputs)

A common misconception is “if an ac multimeter is a true RMS instrument, the multimeter’s sinewave accuracy specifications apply to all waveforms.” Actually, the shape of the input signal can dramatically affect measurement accuracy. A common way to describe signal waveshapes is crest factor. Crest factor of a waveform is the ratio of its peak value to its

RMS value.

Common Crest Factors

The crest factor for a sine wave is √2 = 1.414. For a triangular wave the crest factor is √3 = 1.732. For a square wave with pulse width t and duty cyle T,

√

(see the graphic in the previous section), the crest factor is

For a pulse train, the crest factor is approximately equal to the square root of the inverse of the duty cycle. In general, the greater the crest factor, the greater the energy contained in higher frequency harmonics. All multimeters exhibit measurement errors that are crest factor dependent. HP E1312A and HP E1412A crest factor errors are shown in the AC Characteristics Accuracy Specifications listed in Appendix A with the exception that crest factor errors are not specified for non sine wave input signals below 100 Hz when using the slow ac filter (3 Hz filter).

You can estimate the measurement error for a non-sinusoidal input signal shown below:

Total Error = Error (sine) + Error (crest factor) + Error (bandwidth)

Error (sine): error for sinewave as shown in Appendix A, Specifications. Error (crest factor): crest factor additional error as shown in Appendix A. Error (bandwidth): estimated bandwidth error as shown below.

Example

− (C.F.)

ERROR

C.F. = signal’s crest factor f = signal’s fundamental frequency BW = multimeter’s -3 dB bandwidth

Calculate the approximate measurement error for a pulse train input with a crest factor of 3 and a fundamental frequency of 20 kHz. For this example,

assume the multimeter’s 90-day accuracy specifications: ± (0.05% + 0.03%).

Total Error = 0.08% + 0.15% + 1.4% = 1.6%

(bandwidth)

4 π × BW

× f

× 100%

(1 MHz for the HP E1312A/E1412A)

31 HP E1312A/E1412A Multimeter Application InformationChapter 2

Loading Errors (ac

volts)

In the ac voltage function, the input of the HP E1312A and HP E1412A appears as a 1 MΩ resistance in parallel with 100 pF of capacitance. The

cabling that you use to connect signals to the multimeter will also add additional capacitance and loading.

AC Measurements

Below Full Scale

For low frequencies where

x R

Error (%)

– 100

Rs + 1 MΩ

(f × R

) ≤ 15(106) Ω ⋅Hz:

For any frequen cy :

Error(%) =

= source resistance

100 ×

[

√ 1 + (2 π f C

⋅

1MΩ + R

(1M

Ω)R

)

(

1MΩ + R

1MΩ

) − 1

]

f = input frequency

= input capacitance (100 pF) plus cable capacitance

You can make the most accurate ac measurements when the multimeter is at full scale of the selected range. Autoranging occurs at ≤10% and ≥120% of

full scale. This enables you to measure some inputs at full scale on one range and 10% of full scale on the next higher range (e.g., 10V on the 10V range or 10V on the 100V range). The accuracy will be significantly different for these two cases. For highest accuracy, you should specify the range to assure the lowest range possible for the measurement (this turns autorange off).

Function and Range

Change Internal Offset

Correction

The HP E1312A and HP E1412A uses an ac measurement technique that measures and removes internal offset voltages when you select a different function or range. The next two sections discuss two ways these offset errors can be generated and how the multimeter deals with them.

Temperature Coefficient

Errors

If you leave the multimeter in the same range for an extended period of time, and the ambient temperature changes significantly (or if the multimeter is not fully warmed up), the internal offsets may change. This temperature

coefficient is typically 0.002% of range per °C and is automatically removed when you change functions or ranges.

Overload Errors When you spec ify a n ew ra ng e i n an overload condition, the internal offset

measurement may be degraded for the selected range. Typically, an additional

0.01% of range error may be introduced. This additional error is automatically removed when you remove the overload condition and change function or range; the error remains if the function or range is not changed.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 32

Low-Level

Measurement Errors

When measuring ac voltages less than 100 mV, be aware that these measurements ar e es pe ci al l y su sc ep t ibl e to error s int r od uc ed by ex t rane ous noise sources. Exposed (unshielded) cabling will act as an antenna and a properly functioning multimeter will measure the signals received. The entire measurement path, including the power line, acts as a loop antenna. Circulating currents in the loop will create error voltages across any

impedances in series with the multimeter’s input. For this reason, you should apply low-level ac voltages to the multimeter through shielded cables. You should connect the shield to the input LO terminal.

Make sure the multimeter and the ac source are connected to the same electrical outlet whenever possible. You should also minimize the area of any ground loops that cannot be avoided. Measurements of high-impedance sources are more susceptible to noise pickup than meassurements of lowimpedance sources. You can reduce the noise pick-up by placing a capacitor in parallel with the multimeter’s input terminals. You may have to experiment to determine the correct capacitor value for your application since this capacitance will contribute some loading error.

Most extraneous noise is not correlated with the input signal. You can determine the error as shown below.

√V

Voltage Measured =

Correlated noise, while rare, is especially detrimental because it will always add directly to the input signal. Measuring a low-level signal with the same frequency as the local power line is a common situation prone to this error.

2 + Noise

AC Turnover Errors Errors are generated when the multimeter’s input LO terminal is driven with

an ac voltage relative to earth. The most common situation where unnecessary turnover errors are created is when the output of an ac calibrator is connected to the multimeter “backwards.” Ideally, a multimeter reads the same regardless of how the source is connected. Both source and multimeter effects can degrade this ideal situation.

Because of the capacitance between the input LO terminal and earth (approximately 200 pF for the HP E1312A and HP E1412A), the source will experience different loading depending on how the input is applied. The magnitude of the error is dependent upon the source’s response to this loading. The multimeter’s measurement circuitry, while extensively shielded, responds differently in the backward input case due to slight differences in stray capacitance to earth. Because of this, the 100Vac and 300Vac ranges may latch up for high voltage, high frequency "backward" inputs. Therefore, only drive the high terminal when measuring ac voltages. You can use the grounding techniques described for dc common mode problems to minimize ac common mode voltages (see Common Mode Rejection (CMR)).

33 HP E1312A/E1412A Multimeter Application InformationChapter 2

AC Current Measurement Errors

Burden volt ag e er ro rs , wh ic h ap pl y to dc current, also apply to ac current measurements. However, the burden voltage for ac current is larger due to the

multimeter’s series inductance and your measurement connections. The burden voltage increases as the input frequency increases. Some circuits may oscillate when performing current measurements due to the multimeter’s series inductance and your measurement connections.

Making High-Speed AC Voltage or Current Measurements

The multimeter’s ac voltage and ac current functions implement three different low-frequency filters. These filters allow you to trade low frequency accuracy for faster reading speed. The fast filter settles in 0.1 seconds, and is useful for frequencies above 200 Hz. The medium filter settles in 1 second, and is useful for measurements above 20 Hz. The slow filter settles in 7 seconds, and is useful for frequencies above 3 Hz.

With a few precautions, you can perform ac measurements at speeds up to 50 readings per second. Use manual ranging to eliminate autoranging delays. By setting the preprogrammed settling (trigger) delays to 0, each filter will allow up to 50 readings per second. However, the measurement might not be very accurate since the filter is not fully settled. In applications where sample-tosample levels vary widely, the medium filter (20 Hz) will settle adequately at almost 1 reading per second, and the fast filter (200 Hz) will settle adequately at almost 10 readings per second.

If the sample-to-sample levels are similar, little settling time is required for each new reading. Under this specialized condition, the medium filter will provide reduced accuracy results at 5 readings per second, and the fast filter will provide reduced accuracy results at 50 readings per second. Additional settling time may be required when the dc level varies from sample to sample.

DC Blocking Circuitry The multimeter’s dc blocking circuitry has a settling time constant of 0.2

seconds. This time constant only affects measurement accuracy when dc offset levels vary from sample to sample. If maximum measurement speed is desired in a scanning system, you may want to add an external dc blocking circuit to those channels with significant dc voltages present. This circuit can be as simple as a resistor and a capacitor.

Frequency and Period Measurement Errors

Measurement Configuration

The multimeter uses a reciprocal counting technique to measure frequency and period. This method generates constant measurement resolution for any input frequency. The multimeter’s ac voltage measurement section performs input signal conditioning. All frequency counters are susceptible to errors when measuring low-voltage, low-frequency signals. The effects of both internal noise and external noise pickup are critical when measuring “slow” signals. The error is inversely proportional to frequency. Measurement errors will also occur if you attempt to measure the frequency (or period) of an input following a dc offset voltage change. You must allow the multimeter’s input dc blocking capacitor to fully settle before making frequency measurements.

This section contains information to help you configure the multimeter for making measurements. The parameters discussed in this section give you measurement flexibility when using the CONFigure command.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 34

AC Signal Filter The HP E1412A Multimeter has three different ac filters which enable you to

either optimize low frequency accuracy or achieve faster ac settling times for ac voltage or ac current measurements. Only these functions use the ac filter.

DC Input Resistance

AC Voltage or Current

Input Frequency AC Filter Selected

3 Hz to 300 kHz Slow filter 1 reading/ 7 seconds

20 Hz to 300 kHz Medium filter 1 reading/second

200 Hz to 300 kHz Fast filter 10 readings/second

NOTE: These reading rates account for only the AC filters behavior. See Page 33 for the effect of DC blo cking circuitry.

•

The ac filter selection is stored in volatile memory. Default is the

Max Reading Rate for

Adequate Settling

medium filter (20 Hz - 300 kHz) at power-on or after a module reset.

• The CONFigure and MEASure:<function>? commands

automatically select the medium (20 Hz) filter.

• Use the [SENSe:]DETector:BANDwidth 3 | 20 | 200 | MIN | MAX

command to change the ac filter selection following a CONFigure command. The MIN parameter will select the 3 Hz filter and the MAX parameter will select the 200 Hz filter.

The HP E1412 Multimeter’s input resistance is normally fixed at 10 MΩ for all dc voltage ranges to minimize noise pickup. You can set the input

resistance to greater than 10 GΩ for the 100 mVdc, 1 Vdc and 10 Vdc ranges to reduce the effects of measurement loading errors. You select increased input resistance using the INPut:IMPedance:AUTO ON command and this applies to the dc voltage function only.

INP:IMP:AUTO OFF (DEFAULT)

INP:IMP:AUTO ON

•

The input resistance setting is stored in volatile memory.

INPut:IMPedance:AUTO OFF is set at power-on and after a module

DC Input Resistance 100 mV, 1V, 10V ranges

Ω

10 M

Ω

>10 G

DC Input Resistance 100V and 300V ranges

Ω

10 M

10 MW

reset.

• The CONFigure command and the MEASure:<function>? command

automatically turn AUTO OFF. Use

INPut:IMPedance:AUTO ON

after a CONFigure command to set it ON.

Resolution Resolution is expressed in terms of number of digits the multimeter can

measure. You can set the re so l uti o n to 4 1/ 2 , 5 1/2 or 6 1/2 di gi ts by specifying the integration time (PLCs or aperture time), which is the period the multimeter’s analog-to-digital (A/D) converter samples the input signal

35 HP E1312A/E1412A Multimeter Application InformationChapter 2

for a measurement. To increase measurement accuracy and improve noise rejection, specify more PLCs (longer integration time). To increase measurement speed, specify fewer PLCs (shorter integration time). This applies to all measurement functions.

The resolution for math operations is the same resolution for the measurement function being measured. The table below illustrates the correlation between Number of Power Line Cycles and Resolution. See the tables at the beginning of Chapter 3, Command Reference, for detailed cross-reference of function ranges to resolution as a function of NPLCs or Aperture Time.

Number of Power Line Cycles

(NPLC) Resolution

0.02

0.2 1

100

•

Resolution is stored in volatile memory. The multimeter sets itself to

0.0001 X Full-Scale

0.00001 X Full-Scale

0.000003 X Full-Scale

0.000001 X Full-Scale

0.0000003 X Full-Scale

10 PLCs at power-on or after a module reset.

• DC voltage ratio measurements use both the HI-LO input terminals

(input signal) and the HI-LO "Ω 4W Sense" terminals (the reference signal). The resolution specified applies to the input signal applied to the HI-LO input terminals for ratio measurements and not the reference signal applied to the "Sense" terminals.

• Set the resolution using the following commands:

CONFigure:<function> < MEASure:<function>? < [SENSe:]<function>

range

resolution

>|MIN|MAX,<

|MIN|MAX

resolution

>|MIN|MAX

Integration Time Integration time is the period during which the multimeter’s analog-to-digital

(A/D) converter samples the input signal for a measurement. Integration time affects the measurement resolution (for better resolution, use a longer integration time), and measurement speed (for faster measurement, use a shorter integration time).

• Integration time applies to dc voltage, dc current, resistance and

four-wire resistance functions only. The integration time for the math operations is the same as the integration time for the measurement function in use.

• Except for FREQuency and PERiod functions, integration time is

usually specified in number of power line cycles (NPLC). The default NPLC is 10. You can also specify an integration time in seconds for dc voltage, dc current, resistance, four-wire resistance,

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 36

frequency and period using the aperture time command for each function. Aperture time has a direct correlation to NPLC (except for the FREQuency and PERiod functions which do not use NPLC) and is shown in the tables at the beginning of Chapter 3, Command Reference. See the [SENSe:]FREQ:APER and [SENSe:]PER:APER commands for setting frequency and period aperture time.

• The integration time is stored in volatile memory. The multimeter

selects 10 PLCs at power-on or after a module reset. See following information for FREQuency and PERiod aperture time.

• Only integral numbers of power line cycles (1, 10 or 100 PLCs)

provide normal mode (line frequency noise) rejection.

• You cannot control the reading rate for ac measurements with

integration time because integration time is fixed at 10 PLCs for all ac measurements. You must use a trigger delay to pace ac voltage and ac current measurements.

• NPLCs are not applicable to the FREQuency and PERiod functions.

Frequency and period measurements set resolution by specifying aperture time. The aperture time for the FREQuency and PERiod functions default to 100 mS. Specify an aperture time of 10 mS for 4 1/2 digits, 100 mS for 5 1/2 digits or 1 second for 6 1/2 digits of resolution.

• Set integration time using the following commands:

[SENSe:]<function>:NPLC <number> (NPLCs are not applicable for the FREQ and PER functions) [SENSe:]<functi o n>: APER <s ec on ds >

Autozero Autozero applies to dc voltage, dc current and 2-wire resistance

measurements. The multimeter internally disconnects the input signal following ea ch meas ur em e nt an d t ak es a zero reading when autozero is enabled. Autozero enabled is the default setting. It then subtracts the zero reading from the preceding reading. This prevents offset voltages present on

the multimeter’s input circuitry from affecting measurement accuracy.

• When autozero is disabled (OFF), the multimeter takes one zero

reading and subtracts it from all subsequent measurements. It takes a new zero reading each time you change function, range or integration time. You can disable autozero on dc voltage, dc current and 2-wire ohms measurements only (it is always disabled for ACV and ACI functions). Autozero is always enabled when you select 4-wire ohms or ratio measurements.

• The autozero mode is stored in volatile memory. The multimeter

automatically enables autozero at power-on and after a module reset.

• Use the following command to disable autozero or select the ONCE

parameter. The OFF and ONCE parameters have a similar effect. Autozero OFF does not perform a new zero measurement. Autozero ONCE performs an immediate zero measurement.

37 HP E1312A/E1412A Multimeter Application InformationChapter 2

[SENSe:]ZERO:AUTO OFF |ONCE | ON

Ranging You can let the multimeter automatically select the range using autoranging or

you can specify a range. If you specify an expected value for the signal you are measuring, the multimeter selects the range to accommodate the expected input signal and turns autoranging off. Specify a range for faster measurements to eliminate the autoranging time.

• T he multimeter has autorange mode enabled at power-on and after a

module reset.

• Autorange thresholds:

Down range at <10% of range. Up range at >120% of rang e.

• The multimeter will provide an overload indication by returning

"9.90000000E+37" if the input signal is greater than the present range can measure and autoranging is disabled or at the maximum range setting.

• The multimeter uses one "range" for all inputs between 3 Hz and 300

kHz for the frequency and period functions. The multimeter determines an internal resolution based on a 3 Hz signal. If you query the range, the multimeter will respond with "3 Hz". Frequency and period measurements return "0" with no input signal applied.

• The specified range applies to the signal connected to the Input

terminals for ratio measurements. Autoranging is automatically selected for reference voltage measurements on the Sense terminals.

• You can set the range using any of the following commands:

CONFigure:<function> <range>|MIN|MAX|DEF,<resolution>|MIN|MAX|DEF MEASure:<function>? <range>|MIN|MAX|DEF,<resolution>|MIN|MAX|DEF

[SENSe:]<function>:RANGe <range>|MIN|MAX [SENSe:]<function>:RANGe:AUTO OFF|ON

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 38

Math Operations (CALCulate Subsystem)

AVERage Function The AVERage function allows you to store the minimum and the maximum

This sections provides more information about using the math functions in the CALCulate command. The math operations and registers used to store mathmatical data are controlled using the CALCulate command subsystem. See Chapter 3, HP E1312A and HP E1412A multimeter Command Reference. There are two steps to initiating a math operation.

1. Select the desired math function:

CALCulate:FUNCtion NULL | DB | DBM | AVERage | LIMit

2. Enable the selected math function by turning the calculate state on:

CALCulate:STATe ON

reading from a group of measurements then calculate the average value of all the readings. It also records the number of readings taken since the average function was activated.

The first reading that the multimeter takes is stored as both the minimum and maximum value following activation of the average function. The minimum value is replaced with any subsequent value that is less. The maximum value is replaced with any subsequent value that is greater.

NULL (Relative)

Function

The minimum, maximum, average and count are stored in volatile memory. The multimeter clears the values when the average function is turned on, when power is turned off or after the module is reset.

You use the following commands to activate the average function and query the results from the group of measurements made following activation.

CALCulate:FUNCtion AVERage selects the average function CALCulate:STATe OFF | ON activates the average function

take measurements here

CALCulate:AVERage:MINimum? read the minimum value CALCulate:AVERage:MAXimum? read the maximum value CALCulate:AVERage:AVERage? read the average value CALCulate:AVERage:COUNt? read the number of measurements

A null measurement, also called relative, provides the difference between a stored null value and the input signal. One possible application is in making more accurate two-wire ohms measurements by nulling the test lead resistance .

Result = reading - null value

• Does not apply to the DC-to-DC Ratio measurements.

39 HP E1312A/E1412A Multimeter Application InformationChapter 2

• The null value is adjustable and you can set it to any value between 0

and ±120% of the highest range, for the present function.

• Clearing the NULL value. The null value is stored in volatile

memory; the value is cleared when power is removed, after resetting the multimeter or after a function change.

Two Ways to Store the

NULL Offset Value

•

The null value is stored in the multimeter’s Null Register. You can enter a specific number into the null register using the CALCulate :NULL:OFFSet <value> command. Any previously stored value is replaced with the new value. Use the following commands to activate the NULL function and input a null value. The calculate state must be en ab led bef or e yo u ca n sto re a val u e in t he Nu ll Register.

CONF:<function> clears the null offset value CALCulate:FUNCtion NULL set math function to NULL CALCulate:STATe ON enable math operation CALCulate:NULL:OFFSet <value> store a null offset value

• Another way to enter the null value is to let the multimeter store the

first reading in the register. After you enable the NULL function with the CALC:STATe ON command, the first measurement you obtain will be zero (if you have not stored a value as described in the previous bullet). The measured value is stored as the NULL offset value and subtracted from itself to result in the zero reading. All subsequent measurements will have the offset value subtracted from them. If you previously stored a NULL offset value using CALC:NULL:OFFS <value> as in the commands in the above bullet, the first reading does not overwrite the stored offset value but returns with the previous offset value subtracted.

CONF:<function> clears the null offset value CALCulate:FUNCtion NULL set math function to NULL CALCulate:STATe ON enable math operation ** set up the system to generate the offset of concern (e.g., short ** input leads for 2-wire ohms measurements that will follow) READ? measures and stores the offset value

dB Measurements Each dB measurement is the di ffer en ce bet we en th e i np ut sig na l and a stor ed

relative value, with both values converted to dBm.

dB = reading in dBm - relative value in dBm

• Applies to dc voltage and ac voltage measurements only.

• The relative value is adjustable and you can set it to any value

between 0 dBm and ±200.00 dBm (well beyond the multimeter’s measurement capabilities).

• Clearing the relative value. The relative value is stored in volatile

memory; the value is cleared when power is removed, after the module is reset or after a function change.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 40

Storing the dB Reference

Value

Do not confuse this operation with the dBm reference (DBM) function. See

the next section, "dBm Measurements", and take note of the multimeter’s reference resistance setting (dB uses a reference level, dBm uses a reference resistance).

• The dB reference value is stored in the multimeter’s dB Relative

Register. You can enter a specific number into the register using the CALCulate:DB:REFerence <value> command. Any previously stored value is replaced with the new value. Use the following commands to activate the dBm function and input a reference value. The calculate state must be enabled before you can store a value in the dB Relative Register.

CALCulate:FUNCtion DB set math function to DB CALCulate:STATe ON enable math operation CALCulate:DB:REFerence <value> store a dB reference value

dBm Measurements The dBm operation cal cu lat e s the pow e r de li ve re d to a resi s t an ce refer en ced

to 1 milliwatt.

Storing the dBm

Reference Resistance

Value

dBm = 10

• Applies to dc voltage and ac voltage measurements only.

• You can choose from 17 different reference resistance values. The

× log

(reference resistance) × (1 mW)

reading

factory setting for the reference resistance is 600Ω. Set your desired value with the CALC:DBM:REF <value> command.

The choices for <value> are: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500, 600, 800, 900, 1000, 1200, or 8000 ohms.

• The reference resistance is stored in non-volatile memory, and does

not change when power is removed or after the multimeter is reset.

Do not confuse this operation with the dB reference (DB) function. See the previous section, "dB Measurements", and take note of the multimeter’s dB reference setting (dB uses a reference level, dBm uses a reference resistance).

• Use the following commands to activate the dBm function and input

a reference resistance value. The calculate state must be enabled before you can store a value in the Reference Resistance Register.

CALCulate:FUNCtion DBm set math function to DBm CALCulate:STATe ON enable math operation CALCulate:DBM:REFerence <value> store a dBm reference

41 HP E1312A/E1412A Multimeter Application InformationChapter 2

LIMit Function The limit test operation enables you to perform pass/fail testing against limits

you specify using the CALCulate:LIMit:UPPer and LOWer commands.

• Applies to all measurement functions.

• You can set the upper and lower limits to any value between 0 and

±120% of the highest range, for the present function. The upper

limit selected should always be a more positive number than the lower limit. The default upper and lower limits are both "0".

• The upper and lower limits are stored in volatile memory; the

multimeter sets both limits to 0 when power is removed from the multimeter, after the multimeter is reset or after a function change.

• You can configure the multimeter to generate a request for service

(SRQ) on the first occurrence of a failed reading. See the Status System Register Diagram in the STATus command in Chapter 3, Command Reference. Bits 11 and 12 of the Questionable Data Register provide the high and low limit error signals that can be enabled in the status byte to generate the request for service.

• Use the following commands to activate the LIMit function and input

upper and lower limit values. The calculate state must be enabled before you can store a value in the Upper Limit and Lower Limit Registers.

CALCulate:FUNCtion LIMit CALCulate:STATe ON CALCulate:LIMit:UPPer <value> CALCulate:LIMit:LOWer <value>

• The STATus:QUEStionable:CONDition register will indicate when

an upper or lower limit has been exceeded failing either a HI or LO limit test. Use the STAT:QUES[:EVEN]? command to query the status questionable register and determine what failure occurred. Sending this command also clears the questionable data register (or send a Clear Status *CLS command to clear the register before testing begins).

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 42

Triggering the Multimeter

This section discusses the multimeter’s trigger system and outlines the different triggering configurations and programming methods used to control the trigger system. Keep in mind that you do not have to program the trigger system to make measurements. You can avoid having to learn the information in this section by using the default trigger configuration set by MEASure and CONFigure commands. However, you’ll need the information in this section to take advantage of the flexibility of the HP E1312A/E1412A trigger system when using the CONFigure command.

The multimeter’s trigger system synchronizes measurements with specified internal or external events. These events include software trigger commands, negative-going edges on the VXIbus trigger lines (TTLT0 - TTLT7), and negative-going pulses on the multimeter’s external trigger ("Trig") BNC connector. The trigger system also allows you to specify the number of triggers that will be accepted, the number of readings per trigger (sample count), and the delay between the trigger and each reading.

The diagram below illustrates the multimeter’s trigger system and the programming commands that control the trigger system. The multimeter operates in one of two trigger states. When you are configuring the multimeter for measurements, the multimeter must be in the idle state. After configuring the multimeter, the multimeter must be placed in the wait-for-trigger state.

Triggering the multimeter is a multi-step process.

43 HP E1312A/E1412A Multimeter Application InformationChapter 2

Triggering the multimeter is a multi-step process that offers triggering flexibility.

1. You must configure the multimeter for the measurement by selecting the function, range, resolution, etc.

2. You must specify the source from which the multimeter will accept the trigger. The multimeter will accept a BUS trigger from the VXIbus, an external trigger from the front panel "Trig" BNC

connector or an immediate trigger from the multimeter’s internal trigger system.

3. You must make sure that the multimeter is ready to accept a trigger from the specified trigger source (this is called the wait-for-trigger state) by issuing a READ? or INIT command. A MEAS:<FUNC>? command always uses an immediate trigger (see the flow chart on the precedi ng pag e) .

The Trigger Source The TRIGger:SOURce <source> command configures the multimeter’s

trigger system to respond to the specified source. The following trigger sources are avai la bl e :

• BUS: Trigger source is the HP-IB Group Execute Trigger (GET) or

the *TRG common command. Within the HP 75000 Series C mainframes, the instrument whose trigger source is “ BUS” and was the last instrument addressed to listen will respond to the HP-IB Group Execute Trigger. The *TRG command differs from GET because it is sent to a specific instrument not a group of instruments. NOTE: B-size controllers do not support the BUS trigger (e.g., HP E1306A command module, E1300/E1301A B-size mainframes).

• EXTernal: Trigger source is the multimeter’s external trigger BNC

connector (labeled "Trig" on the front panel). A falling (negativegoing) edge of the input signal triggers the multimeter. The external

pulse signal must be >1 µs, +5V maximum to 0V (TTL levels).

• IMMediate: Internal trigger is always present. If the multimeter is in

the wait-for-trigger state (INITiate), TRIGger:SOURce IMMediate sends the trigger. The MEASure and CONFigure commands automatically set the trigger source to IMMediate.

• TTLTrg0 through TTLTrg7: Trigger source is the VXIbus TTL

trigger lines. The multimeter is triggered on the falling (negativegoing) edge of a TTL input signal. NOTE: B-size controllers do not support VXIbus TTL triggers (e.g., HP E1306A command module, E1300/E1301A B-size mainframes).

For example, the following program statement selects the external trigger BNC connector as the trigger source.

TRIGger:SOURce EXTernal

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 44

You can change the trigger source only when the multimeter is in the idle state. Attempting to change the trigger source while the multimeter is in the

wait-for-trigger state will generate the “Settings conflict” error.

Checking the Trigger

Source

NOTE

External Triggering

The TRIGger:SOURce? command returns “BUS”, “EXT”, “IMM”, or “TTLTn” to show the present trigger source. The string is sent to the output buffer.

Note that a CONFigure or MEASure? command automatically sets the trigger source to IMMediate. You must follow the CONFigure command with the TRIG:SOUR command to set the trigger source to BUS, EXTernal or to TTLTrg<n>. The MEAS? command always uses TRIG:SOUR IMM.

Use TRIGger:SOURce EXTernal to set the trigger source to external.

• T he trigger signal must be a low-true pulse with a pulse width greater

than 1 µs. The trigger signal level accepted is TTL (+5V maximum negative-going to 0V). See the following diagram for the "Trig" input requirement. The diagram also shows the "VM Complete" output you can use to synchronize with a switch module.

• The multimeter takes one reading (or the number specified by

SAMPle:COUNt) for each external trigger received on the front panel "Trig" BNC connector.

45 HP E1312A/E1412A Multimeter Application InformationChapter 2

Internal Triggering The trigger signal is always present in the internal triggering mode. This

mode is selected with the TRIGger:SOURce IMMediate command.

• The multimeter takes one reading (or the number specified by

SAMPle:COUNt) immediately after a READ? or INITiate command. The multimeter takes only one reading immediately following a ME A S? co m m an d.

• See the triggering process diagram at the beginning of this

"Triggering" section.

Bus Triggering The multimeter is triggered from the VXIbus. This mode is selected with the

TRIGger:SOURce BUS command.

NOTE TRIG:SOUR BUS is not implemented on B-size resource managers such as the E1306A comman d module or the E1300A and E1301A B-size mainframes.

The Wait-for-Trigger

State

• Use the *TRG command from the HPIB to trigger the multimeter

when TRIG:SOUR BUS is used. The *TRG command will not be accepted unless the multimeter is in the wait-for-trigger state.

• You can also trigger the multimeter from the HP-IB interface by

sending the IEEE-488 Group Execute Trigger (GET) message. The multimeter must be in the wait-for-trigger state. Send a GET from a Hewlett-Packard controller with the following command:

TRIGGER 70903

You must place the multimeter in the wait-for-trigger state after you have configured it and selected a trigger source. A trigger will not be accepted until the multimeter is in this state. The measurement sequence begins when the multimeter is in the wait-for-trigger state and it receives a trigger.

You can place the multimeter in the "wait-for-trigger" state by executing one of the following commands:

READ? INITiate

NOTE

The multimeter requires approximately 20 ms of set up time after you send a command to change to the "wait-for-trigger" state. Any triggers that occur during this set up time are ignored.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 46

The Trigger Count The TRIGger:COUNt <number> command sets the number of triggers the

multimeter will accept in the wait-for-trigger state before returning to the idle state. Use the number parameter to set the trigger count to a value between 1 and 50,000. The MEASure and CONFigure commands set trigger count to 1.

Substituting MIN for the number parameter sets the trigger count to 1. Substituting MAX for the number parameter sets the trigger count to 50,000.

Example: Setting the

Trigger Count

In the following example, one DC voltage measurement is made each time the

multimeter’s external trigger BNC connector is pulsed low. After 10 external triggers are received, the multimeter returns to the idle state.

dimension array Dimension computer array CONF:VOLT:DC Function: DC voltage TRIG:SOUR EXT Trigger source is external BNC

on multimeter front panel

TRIG:COUN 10 Multimeter will accept 10

external triggers (one measurement is tak e n per trigger)

READ? Place multimeter in

wait-for-trigger state; make measurements when external trigger is received; send readings to output buffer

timeout may occur may require INIT, monitor the

status byte for completion (standard event bit 0), FETC? to transfer readings to the output buffer (vs READ?)

enter statement Enter readings into computer

Checking the

Trigger Count

The TRIGger:COUNt? [MINimum | MAXimum] command returns one of the following numbers to the output buffer:

• The present trigger count (1 through 50,000) if neither MIN nor

MAX is specified.

• T he minimum trigger count available (1) if MIN is specified.

• The maximum trigger count available (50,000) if MAX is specified.

47 HP E1312A/E1412A Multimeter Application InformationChapter 2

Inserting a

Trigger Delay

The TRIGger:DELay <seconds> command inserts a delay between the trigger and each measurement. This includes a delay between the trigger and the first measurement and again before each subsequent measurement when sample count is greater than one. The <seconds> time parameter sets the delay to a

value between 0 and 3600 seconds (with 1 µs resolution).

Substituting MIN for the <seconds> time parameter sets the trigger delay to 0. Substituting MAX for the <seconds> time parameter sets the trigger delay to 3600 seconds.

Example: Inserting a

Trigger Delay

In the following example, the multimeter will accept 5 triggers from the external trigger BNC connector. Four measurements are taken per trigger (sample count is set to 4) and the trigger delay is 2 seconds.

dimension array Dimension computer array CONF:VOLT:DC Function: DC voltage TRIG:SOUR EXT Trigger source is external BNC

on multimeter front panel

TRIG:COUN 5 Multimeter will accept 5

external triggers (one measurement is tak e n per trigger)

SAMP:COUN 4 Take 4 measurements for each

trigger.

TRIG:DEL 2 Wait 2 seconds between trigger

and start of first meas ur eme nt and each subsequent measurement till sample count reached

READ? Place multimeter in

wait-for-trigger state; make measurements when external triggers are received; send readings to output buffer

timeout may occur may require INIT, monitor the

status byte for completion (standard event bit 0), FETC? to transfer readings to the output buffer (vs READ?)

enter statement Enter readings into computer

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 48

Default Delays If you do not specify a trigger delay, the multimeter automatically determines

a delay time (default delay) based on the present measurement function, range, resolution, integration time and AC filter bandwidth setting. The delay time is actually the settling time required before measurements to ensure measurement accuracy. The default delay time is automatically updated whenever you change the function or range. Once you specify a delay time value, however, the value does not change until you specify another value, reset the multimeter or do a CONF or MEAS command. The table below shows the default trigger delay times for all functions. This delay will occur before each measurement (see the trigger system diagram on page 34).

NOTE: You can specify a shorter delay time than the default values shown. However, the shorter settling time may not produce accurate measurements.

Default Trigger Delays for DC Voltage and DC Current (all ranges):

Integration Time Trigger Delay

NPLC ≥1 NPLC <1 1.0 ms

Default Trigger Delays for 2-Wire and 4-Wire Resistance:

Range Trigger Delay

(For NPLC ≥1)

Ω

100

Ω

10 k

Ω

100 k

Ω

1 M

Ω

10 M

Ω

100 M

Default Trigger Delays for AC Voltage and AC Current (all ranges):

AC Filter Trigger Delay

3 Hz - 300 kHz filter 7.0 sec

1.5 ms 1.0 ms

1.5 ms 10 ms 100 ms 100 ms 100 ms 100 ms

1.5 ms

Trigger Delay

(For NPLC <1)

20 Hz - 300 kHz filter 1.0 sec

200 Hz - 300 kHz filter 600 ms

Default Trigger Delay for Frequency and Period:

1.0 s

49 HP E1312A/E1412A Multimeter Application InformationChapter 2

Querying the

Delay Time

The TRIGger:DELay? [MINimum|MAXimum] command returns one of the following numbers to the output buffer:

• The present trigger delay (1 µs through 3600 seconds) if MIN or

MAX is not specified.

• The minimum trigger delay available (1 µs) if MIN is specified.

• The maximum trigger delay available (3600 seconds) if MAX is

specified.

The Sample Count The SAMPle:COUNt <number> command designates the number of readings

per trigger. The number parameter sets the number of readings to a value between 1 and 50,0 00 .

Substituting MIN for the number parameter sets the number of readings per trigger to 1. Substituting MAX for the number parameter sets the number of readings per t ri g ge r to 50 ,0 00 .

Example: Setting the

Sample Count

Checking the

Sample Count

In the following example, 10 DC voltage measurements are made when the

multimeter’s external trigger BNC connector is pulsed low. After the 10 readings are taken, the multimeter returns to the idle state.

dimension array Dimension computer array CONF:VOLT:DC Function: DC voltage TRIG:SOUR EXT Trigger source is external BNC

on multimeter front panel

SAMP:COUN 10 Specify 10 readings per trigger READ? Place multimeter in

wait-for-trigger state; make measurements when external trigger is received; send readings to output buffer

timeout may occur may require INIT, monitor the

status byte for completion (standard event bit 0), FETC? to transfer readings to the output buffer (vs READ?)

enter statement Enter readings into computer

The SAMPle:COUNt? [MINimum|MAXimum] command returns one of the following numbers to the output buffer:

• The present sample count (1 through 50,000) if neither MIN nor

MAX is specified.

• The minimum sample count available (1) if MIN is specified.

• The maximum sample count available (50,000) if MAX is specified.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 50

HP E1312A and HP E1412A Multimeter Application Examples

This section contains example programs that demonstrate several applications using the HP E1312A or HP E1412A Multimeter. The examples described in this section list only the SCPI commands (see Chapter 3, HP E1312A and HP E1412A Command Reference) required to perform the application. The programming language is not included in print but C and Visual Basic programs are included on the VXIplug&play driver media under the subdirectory "examples".

HP VTL Software

(VISA)

Application example programs provided with the HP E1312A or HP E1412A Multimeter are written using VTL 3.0 (VISA Transition Language). VISA(Virtual Instrument Software Architecture) is an I/O library that can be used to create instrument drivers and I/O applications. Application programs written with VTL function calls can use VXIplug&play drivers (or SCPI commands) in systems that have the VTL I/O layer. VTL allows you to use software from different vendors together on the same platform. VTL can be

used for I/O application development on Microsoft® Windows 3.1©, and is supported on the VXI, GPIB-VXI, and GPIB interfaces. VISA 1.0 provides more VISA functionality and is fully operational on Windows 95© and Windows NT©.

Example Programs Example programs are provided on the VXIplug&play media. These

programs have been compiled and tested using Microsoft® Visual C++ Version 1.51 for the C programs and Microsoft® Visual Basic 3.0.

C Programs All projects written in C programming language require the following settings

to work properly. Project Type: QuickWin application (.EXE) Project Files: <source code file name>.C

[drive:]\VXIPNP\WIN\LIB\MSC\VISA.LIB (Microsoft® compiler) [drive:]\VXIPNP\WIN\LIB\BC\VISA.LIB (Borland® compiler)

Memory Model: Options | Project | Compiler | Memory Model Directory Paths: Options | Directories

Include File Paths: [drive:]\VXIPNP\WIN\INCLUDE Library File Paths: [drive:]\VXIPNP\WIN\LIB\MSC (Microsoft®)

[drive:]\VXIPNP\WIN\LIB\BC (Borland®)

Example progra m s: [drive:]\VXIPNP\WIN\hpe1412\EXAMPLES

[drive:]\VXIPNP\WIN\hpe1312\EXAMPLES\C

⇒ Large

Visual Basic Programs All projects written in the Visual Basic programming language require the

following settings to work properly. Project Files: <source code file name>.FRM

[drive:]\VXIPNP\WIN\INCLUDE\VISA.BAS

Hardware Used 486 IBM compatible computer running Windows 3.1. The computer has an

HP 82341 HP-IB interface and HP SICL/Windows 3.1 & Windows/NT for HP-IB software. The VXI modules were loaded in a VXI C-size mainframe using an HP E1406A or B-size mainframe with E1306A Command Module as resource manager connected to the computer via the HP 82341 HP-IB card.

51 HP E1312A/E1412A Multimeter Application InformationChapter 2

Making Multimeter

Measurements

This section provides four programs that demonstrate different ways of making measurements and retrieving the readings. SCPI command sequences for each program are contained in the boxes. The four programs:

1. Use the MEASure command to make a single measurement.

2. Make several externally triggered measurements.

3. Maximize measurement speed on multiple measurements.

4. Maximize measurement accuracy on multiple measurements.

NOTE: Review the section titled "Triggering the Multimeter" just preceding these application examples to fully understand the triggering system.

MEASure Command The simplest measurement method is using the MEASure command which

configures the function to be measured, initiates the measurement(s) and places the reading(s) directly into the output buffer. You then must provide the I/O construct to retrieve the readings and enter them into the computer. One MEASure command will initiate multiple measurements if the trigger count or the sample count is greater than 1. The measurement process stops when the output buffer fills if readings are not retrieved fast enough. The measurement process restarts when there is again room to store readings in the output buffer.

READ? Command The READ? command requires that you configure the multimeter for the

function you want to measure prior to issuing the command. The command initiates the measurement(s) and places the reading(s) directly into the output buffer like the MEASure command. You then must provide the I/O construct to retrieve the readings and enter them into the computer. One READ? command will initiate multiple measurements if the trigger count or the sample count is greater than 1. The measurement process stops when the output buffer fills if readings are not retrieved fast enough. The measurement process restarts when there is room to store readings in the output buffer.

INIT and FETC?

Commands

The READ? command is broken down into two operations with the INIT and FETC? commands. The INIT and FETC? commands require that you configure the multimeter for the function you want to measure prior to issuing the commands. The INIT command initiates the measurement(s) and places

the reading(s) into the multimeter’s RAM memory. This memory will hold a maximum of 512 readings. You use the FETC? command to transfer the readings from memory to the output buffer. You then must provide the I/O construct to retrieve the readings and enter them into the computer. One INIT command will initiate multiple measurements if the trigger count or the sample count is greater than 1. If more than 512 measurements are made, only the last 512 readings are stored. Use the READ? command for more than 512 readings since readings are immediately put into the output buffer and retrieved with an I/O construct you supply. The measurement process stops when the output buffer fills if readings are not retrieved fast enough. The measurement process restarts when there is again room to store readings in the output buffer.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 52

Measurment Format Readings in the output buffer have the following characteristics:

• Readings sent to the output buffer can consist of two different

lengths (bytes or characters) in Real ASCII format:

±1.23456E±12 LF or ±1.234567E±12

• Each measurement is terminated with a Line Feed (LF). The HP-IB

End-or-Identify (EOI) signal is sent with the last byte transferred. If multiple measurements are returned, the measurements are separated by commas and EOI is sent only with the last byte. For example:

±1.23456E±12 LF,±1.234567E±12 LF,±1.23456E±12 LF EOI

• The multimeter’s internal memory stores 512 readings maximum.

MEASURE1 Source Code

File

Comments

MEASURE2 Source Code

File

Use the MEAS Command to Make a Single Measurement

*RST reset the multimeter MEAS:VOLT:DC? configure dc volts (default settings) and measure

retrieve the reading from the multimeter

enter statement enter reading into computer

•

The MEASure command configures the multimeter for the function specified and initiates the measurement. The reading is stored in the output buffer and you must provide the I/O construct to retrieve the reading and enter it into the computer.

Making Externally Triggered Measurements (multiple triggers/samples)

*RST reset the multimeter CONF:VOLT:DC 18 configure for dc volts, expected input = 18V TRIG:SOUR EXT set trigger source to external TRIG:COUN 3 set trigger count to 3 SAMP:COUN 10 set sample count to 10 per trigger INIT puts multimeter in wait-for-trigger state

EXTernal triggers occur here to initiate measurements measurements are stored in multimeter internal memeory

FETC? transfer measurements from the multimeter internal memory

to the output buffer and retrieve them with the computer

enter statement enter reading into computer

Comments • You must provide a TTL external trigger signal to the HP E1312A or

HP E1412A front panel "Trig" input BNC. Measurements are triggered by low pulses of this signal. Each trigger results in 10 readings.

• T he CONFigure command configures the multimeter for the function

specified. This CONFigure command specifies a range parameter of 18 (expected input is 18V; the multimeter sets a range to accomodate that input which will be 100V). It does not initiate the measurement.

53 HP E1312A/E1412A Multimeter Application InformationChapter 2

• Trigger source (TRIG:SOUR) is set for an external trigger. A trigger

count (TRIG:COUN) of 3 is set; the multimeter will accept three external triggers.

• The sample count (SAMP:COUN) is set for 10 samples per trigger.

• The INITiate command puts the multimeter in the wait-for-trigger state.

The trigger source is an "EXTernal" hardware trigger. You provide this trigger and input it on the "Ext Trig" BNC connector which initiates the measurement process. This will cause the multimeter to make 30 measurements; 10 samples for each of three triggers.

• T he FETCh? command causes the readings to be transferred to the output

buffer and you must provide the I/O construct to retrieve the readings and enter them into the computer.

MEASURE3 Source Code

File

Comments

Maximizing Measurement Speed (no trigger delay, short integration time)

*RST reset the multimeter CONF:VOLT:DC 18 configure for dc volts, expected input = 18V CAL:ZERO:AUTO OFF turn off autozero (makes faster measurements) TRIG:SOUR IMM set the trigger source to immediate TRIG:COUN 3 set trigger count to 3 SAMP:COUN 10 set sample count to 10 INIT INITiate command puts multimeter in wait-for-trigger state;

internal trigger immediately occurs here and measurements

are stored in the multimeter’s internal memeory

FETC? transfer measurements from the multimeter’s internal memory

to the output buffer and retrieve them with the computer

enter statement enter reading into computer

•

The CONFigure command configures the multimeter for the function specified. This CONFigure command specifies a range parameter of 18 (expected input is 18V; the multimeter sets a range to accomodate that input which will be 100V). It does not initiate the measurement.

• The autozero function is disabled to speed up the measurement process.

See the CALibrate:ZERO:AUTO command in the Command Reference for more information.

• Trigger source (TRIG:SOUR) is set for immediate internal triggers. A

trigger count (TRIG:COUN) of 3 is set; the multimeter will accept three triggers.

• The sample count (SAMP:COUN) is set for 10 samples per trigger.

• The INITiate command puts the multimeter in the wait-for-trigger state.

The trigger source is "IMMediate" which specifies the internal trigger source. This trigger occurs immediately and causes the measurement process to begin. This will cause the multimeter to make 30 measurements; 10 samples for each of three internal triggers.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 54

• The FETCh? command causes the readings to be transferred to the output

buffer and you must provide the I/O construct to retrieve the readings and enter them into the computer.

MEASURE4 Source Code

File

Comments

Maximizing Accuracy (most accurate resolution, longer integration time)

*RST reset the multimeter

CONF:VOLT:DC AUTO,MIN configure for dc volts, autorange,

minimum resolution (longest integration time)

TRIG:SOUR EXT set trigger source to external TRIG:COUN 2 set trigger count to 2 SAMP:COUN 10 set sample count to 10 READ? initiate measurements putting them directly into

output buffer; retrieve them with the computer

enter statement enter reading into computer

•

The CONFigure command configures the multimeter for the function specified. This CONFigure command specifies autorange and minimum resolution (the smallest resolution value which is the best resolution). It does not initiate the measurement.

• Specifying a small value for resolution provides the most accurate

measurements. This will increase the integration time (NPLCs) and therefore require more time for the measurements.

• Trigger source (TRIG:SOUR) is set for an external trigger. A trigger

count (TRIG:COUN) of 2 is set; the multimeter will accept two external triggers.

• The sample count (SAMP:COUN) is set for 10 samples per external

trigger.

• The READ? command puts the multimeter in the wait-for-trigger state.

When the first external trigger is received, the measurement process begins. This will cause the multimeter to make 10 measurements for the first external trigger, go to the wait-for-trigger state and take 10 measurements for the second external trigger when received.

• The readings are stored in the output buffer and you must provide the I/O

construct to retrieve the readings and enter them into the computer.

• This example uses the READ? command. Measurements are initiated

with the READ? command which puts the multimeter in the wait-fortrigger state. Measurement occurs when the trigger arrives and readings are subsequently stored directly in the output buffer and must be retrieved by the computer with an I/O construct you supply. An alternative way of intitating measurements is to use the INITiate command as done in the

previous example. Measurements are made and stored in the multimeter’s internal memory and must be retrieved using the FETCh? command which transfers the readings to the output buffer. You must be careful when using the INITiate and FETCh? commands. Internal memory stores a maximum of 512 readings; the oldest readings exceeding 512 are lost.

55 HP E1312A/E1412A Multimeter Application InformationChapter 2

Synchronizing the

Multimeter With a

Switch Module

This program example demonstrates how to synchronize the multimeter with a switch module. For the HP E1412A it uses the TTL triggers from the VXI backplane to trigger the multimeter and advance the channel scan list. The example uses the HP E1476A 64-channel Multiplexer Module but will also work with any HP switch module as long as the channel list is specified properly. Figure 2-1 illustrates the C-size set up. The switch module (multiplexer) and multimeter use the VXI backplane to communicate the trigger and VM Complete signals to each other to synchronize the scan. Figure 2-2 shows the HP E1312A set up using external triggering. B-size command modules do not support VXIbus TTL triggers.

Figure 2-1. HP E1412A Multimeter and Switch Module Synchronization.

Figure 2-2. HP E1312A Multimeter and Switch Module Synchronization.

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 56

This example monitors the switch module’s status system. The switch module’s status system is shown in Figure 2-3. This example program enables the switch’s "Scan Complete" bit to allow it to set the OPR bit in the switch’s status byte when the scan is finished. The program repeatedly reads the switch module’s status byte until the OPR bit gets set which returns a status byte value of 128. This indicates the switch module has completed all closures in the scan list. The multimeter’s FETC? command causes the multimeter to transfer readings to the output buffer after completing the last measurement. Readings are entered into the computer using an I/O construct you provide.

NOTE: This is the HP E1476A

switch module’s status system. See Figure 2-3 for the HP E1312A/ E1412A Multimeter status sys tem .

Figure 2-3. HP E1476A Switch Module Status System.

57 HP E1312A/E1412A Multimeter Application InformationChapter 2

(E1412A) SCAN

Source Code File

(see SCAN1312 example

program for E1312A code

-the E1312A cannot use TTL triggers)

SCPI command se qu en ce s fo r t he pro gr am ar e as foll o w s.

**** Set up the Multimeter ****

*RST reset the multimeter *CLS clear the multimeter’s status registers CONF:VOLT 12,MIN configure for dc volts, 12V input, min res TRIG:SOUR TTLT2 let switch closure trigger multimeter TRIG:COUN 8 multimeter will accept 8 triggers TRIG:DEL 0.01 use a 10 ms delay before

each measurement

OUTP:TTLT1:STAT ON output VM Complete to switch via TTLT1 CALC:FUNC AVER select the math function AVERage CALC:STAT ON enable math operations *OPC? Wait until above commands are processed

read the response to the *OPC? command from multimeter

INIT puts multimeter in the "wait-for-trigger" state;

trigger source is TTLTrig2 line OUTPut by the switch

**** Now set up the switch module ****

*RST reset the switch module *CLS clear the switch module’s status registers ABOR abort any swit c h op er ati o n i n pr og re ss STAT:OPER:ENAB 256 enable bit 8 of operation status register OUTP:TTLT2:STAT ON enable switch closure to trigger multimeter TRIG:SOUR TTLT1 allow VM Complete to advance the scan SCAN (@100:107) specify a switch module scan list *OPC? Wait until above commands are processed

read the response to the *OPC? command from switch

INIT starts scanning by closure of the first channel in the scan list;

sends output signal to multimeter via TTLTrig2 to trigger a measurement; multimeter sends TTLT1 (VM Complete) back to switch module to advance scan to the next channel; measurements are stored in multimeter internal memeory

************************************************************

read switch’s status byte until all channels are scanned and scan complete (bit 8 in the operation status register) sets the OPR bit in the status byte

************************************************************

retrieve the readings from the multimeter

FETC? transfer measurements from the multimeter internal memory

to the output buffer and retrieve them with the computer

retrieve the AVERage math operation response from the multimeter

CALC:AVER:AVER? retrieve the average measurement value CALC:AVER:MAX? retrieve the maximum measurement value CALC:AVER:MIN? retrieve the minimum measurement value

check the multimeter for system errors

SYST:ERR? retrieve the system error response from the multimeter

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 58

Multimeter Status

System Examples

There are two program examples that demonstrate how the HP E1312A and HP E1412A Multimeter status system works. In both programs the status byte is repeatedly read to identify when actions by the Multimeter set the appropriate bit in the status byte. The computer can identify when readings are available by monitoring the status byte and can retrieve readings when they are avail a ble .

Figure 2-4 illustrates the HP E1312A and HP E1412A Status system. A Questionable Data Register, an Output Buffer and a Standard Event Register each have a respec t ive st atu s bi t in t he Sta tus By te R eg ist e r. The Out p ut Buffer sets the MAV bit when there is data available such as measurement readings or a response to a SCPI query command. The Questionable Data Register and Standard Event Register require you to "unmask" the bits you

want to be OR’d into a summary bit which sets the respective bit in the Status Byte. You must also "unmask" the status bits you want OR’d into a summary bit to set the Service Request bit (SRQ) if you want to generate an interrupt. The B-size HP E1312A requ i res yo u un mas k an y bi t wi th t he *SRE co mm an d that you want to read with a SPOLL (the E1412A does not require this unmasking). The example programs illustrate this requirement.

Figure 2-4. HP E1312A/E1412A Multimeter Status System

59 HP E1312A/E1412A Multimeter Application InformationChapter 2

SYNCHOPC Source Code

File

This program has the multimeter take 10 measurements. The Standard Event bit (ESB) in the status byte (see Figure 2-4) is monitored to detect when the operation is complete. Readings are transferred to the output buffer by a FETC? command and retrieved by the computer following the indication that the operaation has completed. The Multimeter then calculates the average, minimum and maximum reading.

set up the multimeter

*RST reset the multimeter *CLS clear the multimeter’s status registers *ESE 1 enables bit 0 of the multimeter’s standard event register CONF:VOLT 15 configure for dc volts, expected input of 15V VOLT:DC:NPLC 10 set number of power line cycles to 10 TRIG:COUN 10 multimeter will accept 10 triggers TRIG:DEL .01 use a 10 ms delay before

each measurement

CALC:FUNC AVER select the math function AVERage CALC:STAT ON enable math operations

*SRE 32 required for the E1312A to detect the bit in an SPOLL INIT puts multimeter in wait-for-trigger state; trig source

is "IMM"; internal trigger occurs "immediately" and measurements are stored in multimeter internal memory

*OPC waits for all measurements to complete then sets bit 0 in the

standard event register (the operation complete bit)

Loop

SPOLL - read the multimeter’s status byte until bit 5 (ESB) goes high End Loop

FETC? transfer measurements from the multimeter internal memory

to the output buffer and retrieve them with the computer

retrieve the AVERage math operation response from the multimeter

CALC:AVER:AVER? retrieve the average measurement value CALC:AVER:MAX? retrieve the maximum measurement value CALC:AVER:MIN? retrieve the minimum measurement value

check the multimeter for system errors

SYST:ERR? retrieve the system error response from the multimeter

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 60

SYNCHMAV Source Code

File

This program has the multimeter take 10 measurements just like SYNCHOPC. Readings are transferred to the output buffer by a FETC? command. The Me ssage Available bi t (M A V) i n the st at u s by te (s ee Fig ur e 2-4) is monitored to detect when the measurements are complete and the Multimeter has readings in the output buffer. Readings are retrieved by the computer when the MAV bit in the status byte indicates the measurements are complete and readings are available. The Multimeter then calculates the average, minimum and maximum reading.

set up the multimeter

*RST reset the multimeter *CLS clear the multimeter’s status registers CONF:VOLT 15 configure for dc volts, expected input of 15V VOLT:DC:NPLC 10 set number of power line cycles to 10 TRIG:COUN 10 multimeter will accept 10 triggers TRIG:DEL .01 use a 10 ms delay before

each measurement

CALC:FUNC AVER select a math function CALC:STAT ON enable the math operations

*SRE 16 required by the E1312A to detect MAV bit in SPOLL INIT puts multimeter in wait-for-trigger state; trigger source

is "IMM"; internal trigger occurs "immediately" and measurements are stored in multimeter internal memory

FETC? transfer measurements from the multimeter internal memory

to the output buffer and retrieve them with the computer

Loop

SPOLL - read the multimeter’s status byte until bit 4 (MAV) goes high to indicate there is a message available in the output buffer.

End Loop

** NOTE: If TRIG:COUN is too big, FETC? can timeout before meassurements complete. FETC? expects a response before the timeout interval specified in the program code. Using the previous program detecting the OPC bit is recommended.

retrieve the AVERage math operation response from the multimeter

CALC:AVER:AVER? retrieve the average measurement value CALC:AVER:MAX? retrieve the maximum measurement value CALC:AVER:MIN? retrieve the minimum measurement value

check the multimeter for system errors

SYST:ERR? retrieve the system error response from the multimeter

61 HP E1312A/E1412A Multimeter Application InformationChapter 2

LIMITTST Source Code

File

This program has the multimeter making measurements continuously until an upper or lower limit is exceeded. The lower test limit is set to 2V; the upper test limit is set to 8V. Questionable data register bits 11 and 12 are unmasked to allow the LO and HI Limit Test Failures to set the QUE bit in the status byte. An input less the 2V or greater than 8V will report a test failure and halt the program.

set up the multimeter

*RST reset the multimeter *CLS clear the multimeter’s status registers CONF:VOLT 10 configure for dc volts, 10V range CALC:STAT ON enable the math function CALC:LIM:LOW 2 set lower limit to 2 CALC:LIM:UPP 8 set upper limit to 8 CALC:FUNC LIM select a math function; set to LIMit STAT:QUES:ENAB 6144 unmask the limit error bits

*SRE 8 required by the E1312A to detect QUE bit in SPOLL

Loop

READ? trigger measurement and place response into the output buffer

Enter response into the computer

SPOLL - read the multimeter’s status byte until bit 3 (QUE) goes high to indicate there is a Limit Test Failure (HI or LO).

wait 1 second

End Loop

check the multimeter for system errors

SYST:ERR? retrieve the system error response from the multimeter

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 62

HP VEE Programming

Example

HP VEE is HP’s Visual Engineering En vi r on men t , a graphical programming language for creating test systems and solving engineering problems. This section provides an instrument control example using the "Direct I/O" feature of HP VEE. Direct I/O allows you to directly specify messages to be sent to an instrument and to directly read the information sent back by an instrument. Direct I/O also offers the most efficient I/O performance in HP VEE.

The example provided here synchronizes a measurement scan with a switch module. This is the same example previously discussed in this chapter with programs provided in the C and Visual Basic programming languages.

Device Configuration You must configure your HP E1312A or HP E1412A Multimeter (and the

switch module) before you can communicate with them.

1. Select I/O

or Configure

2. Select the select

Add Instrument from the Instrument Configure choices. This

selection pops up the

3. Fill in the

Byte Ordering to MSB and Live Mode to ON. Then select Direct I/O

Set

Config...

4. Verify

5. Select

⇒ Instrument... from the menu bar. The Instrument Select

dialog box pops up.

Direct I/O button from the Instrument Type choices. Then

Device Configuration dialog box.

Device Configuration Name, Interface, Address an d Timeout .

The Direct I/O Configuration dialog box pops up.

Conformance is set to IEEE 488 (use default settings for all others).

OK to close both the Direct I/O and Device Configuration boxes.

6. Select the "name" you put in the name field of the device configuration dialog box now appearing in the instrument list and press the

Get Instr button.

Program Description The i ns t ru m en ts ar e pr og ra m m ed usi n g D ire ct I/ O objects connec t ed as

required by the sequence of SCPI commands. Reading of the HP E1476A status byte is performed using the SPOLL whose action is set to

I/O | Advanced I/O | Device Event

ANY SET

and its mask set to

#H80

object

. This mask allows reading only the OPR bit of the status byte (bit 7) which gets set by bit 8 (Scan Complete) from the Operation Status Register when the switch module completes the scan list. Following the detection of scan complete, the readings are retrieved with the Multimeter’s an array format to an HP VEE

E1412A Measurements

Display

object which gives a plot of the measurements.

AlphaNumeric Display object titled

. The readings are also sent to a Strip Chart

FETCh? command and sent in

63 HP E1312A/E1412A Multimeter Application InformationChapter 2

Strip Chart Object

In parallel with the HP E1412A Measurements AlphaNumeric Display object is a Strip Chart Display object that displays the readings of the eight channels. The Strip Chart has an Auto Scale button to automatically scale the horizontal and vertical axis to best display the measured data. Upper and

lower boundary traces could be added to the strip chart’s display.

See your HP VEE documentation and on-line help for more detail on test and measurement I/ O con t ro l . If you ar e no t usi n g HP VE E an d ar e cu ri o us abo ut HP’s graphical programming language, call your local HP sales office listed in your telephone directory for more information. You can get a free HP VEE Evaluation Kit containing detailed technical information and a demo disk that walks you through many of HP VEE’s features and functions. The following brochures provide additional information about HP VEE:

• HP VEE Visual Engineering Environment

P/N 5962-9239E

• HP VEE The Most Productive Language for Test and Measurement

P/N 5963-9528E

• HP VEE Visual Engineering Environment Technical Data

P/N 5091-9554EUS

Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 64

APPLICATION NOTES

65 HP E1312A/E1412A Multimeter Application InformationChapter 2

Chapter 3

Multimeter Command Reference

Using This Chapter This chapter describes the Standard Commands for Programmable

Instruments (SCPI) and IEEE 488.2 Common (*) commands applicable to

the HP E1312A and HP E1412A 6

Command Types Commands are separated into two types: IEEE 488.2 Common Commands

and SCPI Commands.

⁄2-Digit Multimeters.

Common Command

Format

The IEEE 488.2 standard defines the Common commands that perform functions like reset, self-test, status byte query, etc. Common commands are four or five characters in length, always begin with the asterisk character (*), and may include one or more parameters. The command keyword is separated fr om t he fi rs t p aram e t er by a sp ac e ch ar ac t er . Som e ex am p l es of common commands are shown below:

*RST *ESR 32 *STB?

SCPI Command Format The SCPI commands perform functions such as making measurements,

querying instrument states, or retrieving data. The SCPI commands are grouped into command "subsystem structures". A command subsystem structure is a hierarchical structure that usually consists of a top level (or root) command, one or more low-level commands, and their parameters. The following example shows the root command CALibration and its lower-level subsystem commands:

CALibration

Chapter 3 Multimeter Command Reference 66

CALibration is the root command, COUNt?, LFRequency, LFRequency?, SECure, STRing, STRing?, VALue and VALue? are second level commands, and CODE, STATe and STATe? are third level commands.

Command Separator A colon (:) always separates one command from the next lower level

command as shown below:

CALibration:SECure:STATe?

Colons separate the root command from the second level command (CALibration:SECure) and the second level from the third level (SECure:STATe?).

Abbreviated Commands The command syntax shows most commands as a mixture of upper and

lower case letters. The upper case letters indicate the abbreviated spelling for the command. For shorter program lines, send the abbreviated form. For better program readability, you may send the entire command. The instrument will accept either the abbreviated form or the entire command.

For example, if th e co mm an d sy nt a x sh ow s ME ASure, then MEAS and MEASURE are both acceptable forms. Other forms of MEASure, such as MEASU or MEASUR will generate an error. Additionally, SCPI commands are case insensitive. Therefore, you may use upper or lower case letters and commands of the form MEASURE, measure, and MeAsUrE are all acceptable.

Implied Commands Implied commands are those which appear in square brackets ([ ]) in the

command syntax. (Note that the brackets are not part of the command; do not send them to the instrument.) Suppose you send a second level command but do not send the preceding implied command. In this case, the instrument assumes you intend to use the implied command and it responds as if you had sent it. Examine the partial SENSe subsystem shown below:

[SENSe:]

FUNCtion "<function>" (e.g., <function> = VOLT: AC) FUNCtion? RESistance

:RANGe <range>|MIN|MAX :RANGe? [MIN|MAX]

The root command SENSe is an implied command. For example, to set the

multimeter’s function to AC volts, you can send either of the following command statements:

SENS:FUNC "VOLT:AC" or FUNC "VOLT:AC"

67 Multimeter Command Reference Chapter 3

Parameters Parameter Types. The following table contains explanations and examples

of parameter types you might see later in this chapter.

Parameter

Type

Numeric Accepts all commonly used decimal representations of

number including optional signs, decimal points, and scientific notation.

123, 123E2, -123, -1.23E2, .123, 1.23E-2, 1.23000E-01. Special cases include MINimum, MAXimum, and DEFault.

Boolean Represents a single binary condition that is either true or

false. ON, OFF, 1, 0

Discrete Selects from a finite number of values. These parameters

use mnemonics to represent each valid setting. An example is the TRIGger:SOURce <source> command

where source can be BUS, EXT, or IMM.

Explanations and Examples

Optional Parameters. Parameters shown within square brackets ([ ]) are optional parameters. (Note that the brackets are not part of the command; do not send them to the instrument.) If you do not specify a value for an optional parameter, the instrument chooses a default value. For example, consider the TRIGger:COUNt? [MIN | MAX] command. If you send the command without specifying a MINimum or MAXimum parameter, the present TRIGger:COUNt value is returned. If you send the MIN parameter, the command returns the minimum trigger count allowable. If you send the MAX parameter, the command returns the maximum trigger count allowable. Be sure to place a space between the command and the parameter.

Linking Commands Linking IEEE 488.2 Common Commands with SCPI Commands. Use

only a semicolon between the commands. For example:

*RST;RES:NPLC 100 or SAMP:COUNt 25;*WAI

Linking Multiple SCPI Commands From the Same Subsystem. Use only a semicolon between commands within the same subsystem. For example, to set trigger count, trigger delay and the trigger source which are all set using the TRIGger subsystem, send the following SCPI string:

TRIG:COUNt 10;DELay .05;SOURce TTLT4

Linking Multiple SCPI Commands of Different Subsystems. Use both a semicolon and a colon between commands of different subsystems. For example, a SAMPle and OUTPut command can be sent in the same SCPI string linked with a semicolon and colon (;:) as follows:

SAMP:COUNt 10;:OUTP:TTLT4 ON

Chapter 3 Multimeter Command Reference 68

Multimeter Range and Resolution Tables

The following tables list the voltage and resistance ranges available for the multimeter. Also shown are the associated resolution values versus aperture time in seconds or integration time in power line cycles (PLCs) for each range.

Table 3-1. DC Voltage Resolution versus Integration Time or Aperture Time

Integration time in Power Line Cycles (PLCs)

Aperture time for 60 Hz Line Frequency (seconds)

Range

100 mV 120 mV 30 nV 100 nV 300 nV

1 V 1.2 V 300 nV

10 V 12V 100V 120V 300V 300V

Maximum

Reading

100 PLCs

1.67 s

3 µV10 µV30 µV100 µV

30 µV100 µV300 µV

300 µV

10 PLCs

167 ms

1 µV3 µV10 µV100 µV

1 mV 3 mV 10 mV 100 mV

1 PLC

16.7 ms

0.2 PLC

3.33 ms

1 µV10 µV

1 mV 10 mV

Table 3-2. DC Current Resolution versus Integration Time or Aperture Time

Integration time in Power Line Cycles (PLCs)

Aperture time for 60 Hz Line Frequency (seconds)

Range

10 mA 12 mA 3 nA 10 nA 30 nA 100 nA

100 mA 120 mA 30 nA 100 nA 300 nA

Maximum

Reading

100 PLCs

1.67 s

10 PLCs

167 ms

1 PLC

16.7 ms

0.2 PLC

3.33 ms

1 µA10 µA

0.02 PLC

0.333 ms

1 mV

0.02 PLC

0.333 ms

1 µA

1A 1.2A 3 nA 3A 3A 900 nA

1 µA3 µA10 µA100 µA 3 µA9 µA30 µA300 µA

69 Multimeter Command Reference Chapter 3

Table 3-3. 2-Wire and 4-Wire Resistance Resolution versus Integration Time or Aperture Time

Integration time in Power Line Cycles (PLCs)

Aperture time for 60 Hz Line Frequency (seconds)

Range

100Ω 120Ω 30 µΩ 100 µΩ 300 µΩ 1 mΩ 10 mΩ

1 kΩ 1.2 kΩ

10 kΩ 12 kΩ 3 mΩ 10 mΩ 30 mΩ 100 mΩ 1Ω

100 kΩ 120 kΩ 30 mΩ 100 mΩ 300 mΩ 1Ω 10Ω

1 MΩ 1.2 MΩ

10 MΩ 12 MΩ 3Ω

100 MΩ 100 MΩ 30 Ω 100Ω 300Ω 1 kΩ 10 kΩ

Maximum

Reading

100 PLCs

1.67 s

300 mW

10 PLCs

167 ms

1 mΩ 3 mΩ 10 mΩ 100 mΩ

1Ω 3Ω 10Ω 100Ω

10W

1 PLC

16.7 ms

30Ω 100Ω 1 kΩ

0.2 PLC

3.33 ms

0.02 PLC

0.333 ms

Table 3-4. AC Voltage: Range versus Resolution

Resolution choices versus range

RANGE 100 mV 1V 10V 100V 300V

MIN 100 nV

1 µV 10 µV 100 µV

1 mV

power-on &

*RST setting

MAX

1 µV 10 µV 100 µV

10 µV 100 µV

1 mV 10 mV 100 mV

Table 3-5. AC Current: Range versus Resolution

Resolution choices versus range.

RANGE 1A 3A

MIN

power-on &

*RST setting

MAX

1 mV 10 mV

1 µA3 µA

10 µA 30 µA

100 µA 300 µA

Chapter 3 Multimeter Command Reference 70

SCPI Command Reference ABORt

SCPI Command Reference

Command Guides Command guides are printed in the top margin of each page. The left guide

This section describes the Standard Commands for Programmable Instruments (SCPI ) for t he HP E131 2A an d E1 41 2A 6

⁄2-Digit Multimeters.

Commands are listed alphabetically by subsystem and also within each subsystem.

indicates the first command listed on that page. The right guide indicates the last command listed on that page. If a single command appears on a page, the left and right guides will be the same.

ABORt The ABORt command subsystem removes the multimeter from the

wait-for-trigger state and places it in the idle state. ABORt is only effective when the trigger source is TRIGger:SOURce BUS.

Subsystem Syntax ABORt

Example Aborting a Measurement

Comments

CONF:VOLT:DC Function: DC voltage TRIG:SOUR BUS Trigger source is BUS trigger INIT Place multimeter in

ABOR Abort waiting for a trigger and

•

ABORt does not affect any other settings of the trigger system.

wait-for-trigger state

place multimeter in idle state

When the INITiate command is sent, the trigger system will respond as it did before ABORt was executed.

• ABORt returns the multimeter to the idle state for

TRIGger:SOURce BUS. The "Trigger ignored" error is generated when a Group Execute Trigger (GET) bus command or *TRG common command is executed after an ABORt command (which puts the multimeter into the idle state).

• Related Commands: INITiate, TRIGger

• *RST Condition: After a a *RST, the multimeter acts as though an

ABORt has occurred.

71 Multimeter Command Reference Chapter 3

CALCulate CALCulate

CALCulate There are five math operations available (NULL, DB, DBM, AVERage and

LIMit), only one can be enabled at a time. Each performs a mathematical operation on every reading or stores data on a series of readings. The selected math operation remains in effect until you disable it, change functions, turn off the power, or perform a remote interface reset. The math operations use one or more internal registers. You can preset the values in some of the registers, while others hold the results of the math operation.

The following table shows the math/measurement function combinations

allowed. Each “ math operation that is not allowed with the present measurement function, math is turned off. If you select a valid math operation and then change to one that is invalid, a “Settings conflict” error is generated over the remote interface. For null and dB measurements, you must turn on the math

operation before writing to their math registers.

X” indicates an allowable combination. If you choose a

DCV ACV DCI ACI

NULL XXXXXXXX

AVERage XXXXXXXXX

DB X X

DBM X X

LIMit XXXXXXXXX

Subsystem Syntax CALCulate

Ω 2W Ω 4W

Freq Per Ratio

Chapter 3 Multimeter Command Reference 72

CALCulate:FUNCtion CALCulate:STATe

:FUNCtion CALCulate:FUNCtion NULL|DB|DBM|AVERage|LIMit selects the

math function to be used. One function is enabled at a time with NULL the default. The selected function MUST be enabled with CALC:STATe ON.

Parameter Summary

Example Set the calculate math function to make upper and lower limit tests on

•

NULL measurements (also called relative measurements) provide a reading which is the difference between a stored null value and the input signal.

• D B m ea su re m en t s ar e the d iff er en ce bet w e en th e i np ut si g na l and a

stored relative value, with both values converted to dBm.

• DBM operations calculate the power delivered to a resistance

referenced to 1 milliwatt.

• AVERage measurements store the minimum and maximum readings

from a number of measurements. The multimeter records the number of readings taken since the average function was enabled then calculates the average of all the readings. You read these values with CALC:AVER:MIN?; MAX?; AVERage? and COUNt?.

• The LIMit parameter enables pass/fail testing on the upper and lower

limits you specify using the LIMit:UPPer and LIMit:LOWer commands.

• See the section titled "Math Operations" in Chapter 2, Application

Examples, for more detail on the CALCulate operations.

each measurement:

CALC:FUNC LIM Set calculate function to limit.

CALC:LIM:LOWer Set the lower limit to test against. CALC:LIM:UPPer Set the upper limit to test against. CALC:STATe ON Enable the limit math operation.

FUNCtion? CALCulate:FUNCtion? queries the multimeter to determine the present

math function. Returns

Example Query what the calculate math function is:

CALC:FUNC? Query the calculate function.

NULL, DB, DBM, AVER, or LIM.

:STATe CALCulate:STATe OFF | ON disables or enables the se l ec ted ma t h

function. The state is stored in volatile memory.

Example Enable the currently selected calculate math function:

CALC:STAT ON The selected or default math

function is enabled.

73 Multimeter Command Reference Chapter 3

CALCulate:STATe? CALCulate:AVERage:COUNt?

:STATe? CALCulate:STATe? queries the state of the math function. Returns “0”

OFF) or “1” (ON).

(

Example Query whether a math function state is on or off:

CALC:STAT? Query the state.

:AVERage:MINimum? CALCulate:AVERage:MINimum? reads the minimum value found from

an AVERage function operation . The min value is cleared when AVERage is enabled (CALC:FUNC AVER and CALC:STAT ON commands), when power is removed, or after the multimeter is reset. The minimum value is stored in volatile memory.

Example Query the minimum value found during an AVERage math operation:

CALC:AVER:MIN? Query the min value.

:AVERage:MAXimum? CALCulate:AVERage:MAXimum? reads the maximum value found

from an AVERage operation. The max value is cleared when AVERage is enabled (CALC:FUNC AVER and CALC:STAT ON commands), when power is removed, or after the multimeter is reset. The maximum value is stored in volatile memory.

Example Query the maximum value found during an AVERage math operation:

CALC:AVER:MAX? Query the max value.

:AVERage:AVERage? CALCulate:AVERage:AVERage? reads the average of all readings taken

since AVERage was enabled (CALC:FUNC AVER and CALC:STAT ON commands). Th e av er ag e va l ue is cle ared wh en AVE R ag e is en ab l ed , w he n power is removed, or after the multimeter is reset. The average value is stored in volatile memory.

Example Query the average of all readings taken since the AVERage math

operation was enabled:

CALC:AVER:AVER? Query the average of all read ings.

:AVERage:COUNt? CALCulate:COUNt? reads the number of readings taken since AVERage

was enabled (CALC:FUNC AVER and CALC:STAT ON commands). The count value is cleared when AVERage is enabled by the CALC:FUNC AVER and CALC:STAT ON commands, when power has been off, or after a remote interface reset. The number of readings taken is stored in volatile memory.

Chapter 3 Multimeter Command Reference 74

CALCulate:NULL:OFFSet CALCulate:DB:REFerence?

Example Query the number of readings since the AVERage math operation was

enabled:

CALC:COUN? Query number of readings.

:NULL:OFFSet CALCulate:NULL:OFFSet <value> | MIN | MAX stores a null value in

the multimeter’s Null Register. You must turn on the math operation e.g., execute CALC:STAT ON before writing to the math register. You can set

the null value to any number between 0 and ±120% of the highest range, for the present function. highest range. The null value is stored in volatile memory. See the section titled "Math Operations - NULL Function" in Chapter 2 for another way to store the offset value.

Example Set the null offset value:

MIN = –120% of the highest range. MAX = 120% of the

CALC:FUNC NULL Set math function to NULL. You

CALC:STAT ON Turn on math operation. CALC:NULL:OFFS 500 Set null offset to 500.

may choose to set the math function after setting STATe ON.

:NULL:OFFSet? CALCulate:NULL:OFFSet? [MIN | MAX] queries the null value.

Example Query the null offset val ue se t fo r the NULL m ath oper at ion:

CALC:NULL:OFFS? Query the null offset value.

:DB:REFerence CALCulate:DB:REFerence <value>|MIN|MAX stores a relative value

in the dB Relative Register. You must turn on the math operation e.g., execute CALC:STAT ON before writing to the math register. You can set

the relative value to any number between ±200 dBm (the values). The dB reference is stored in volatile memory.

Example Set the DB refere nce va l ue :

CALC:STAT ON Turn on the math operation CALC:DB:REF 60 Sets DB reference to 60 dBm.

CALC:FUNC DB Select the DB math operation.

You can select the calculate function at any time before or after enabling the calculate state.

MIN and MAX

:DB:REFerence? CALCulate:DB:REFerence? [MIN | MAX] queries dB reference value.

Example Query the DB reference va l ue se t fo r the DB ma th oper at ion:

CALC:DB:REF? Query the DB reference value.

75 Multimeter Command Reference Chapter 3

CALCulate:DBM:REFerence CALCulate:LIMit:LOWer?

:DBM:REFerence CALCulate:DBM:REFerence <value> | MIN | MAX selects the dBm

reference value. Choose from: 50, 75, 93, 110, 124, 125, 135, 150, 250, 300, 500, 600 (default), 800, 900, 1000, 1200, or 8000 ohms. MIN = 50Ω .

MAX = 8000Ω. You must turn on the math operation e.g., execute

CALC:STAT ON before writing to the math register. The dBm reference is

stored in non-volatile memory.

Example Set the DBM reference value:

CALC:STAT ON Turn on the math operation CALC:DBM:REF 135 Sets DBM reference value to 135.

CALC:FUNC DBM Select the DBM math operation.

You can select the calculate function at any time before or after enabling the calculate state.

:DBM:REFerence? CALCulate:DBM:REFerence? [MIN | MAX] queries the dBm reference.

Example Query the DBM reference value set for the DBM math operation:

CALC:DBM:REF? Query the DBM reference value.

:LIMit:LOWer CALCulate:LIMit:LOWer <value> | MIN | MAX sets the lower limit

for limit testing. You can set the value to any number between 0 and ±120% of the highest range, for the present function.

MAX = 120% of the highest range. You must turn on the math

range.

MIN = –120% of the highest

operation e.g., execute CALC:STAT ON before writing to the math register. The lower limit is stored in volatile memory.

Example Set the lower limit:

CALC:STAT ON Turn on the math operation CALC:LIM:LOW 1000 Set the lower limit.

CALC:FUNC LIM Select the LIMit math operation.

You can select the calculate function at any time before or after enabling the calculate state.

:LIMit:LOWer? CALCulate:LIMit:LOWer? [MIN | MAX] queries the lower limit.

Example Query the lower limit set for the LIMit math operation:

CALC:LIM:LOW? Query the lower limit.

Chapter 3 Multimeter Command Reference 76

CALCulateLIMit:UPPer CALCulate:LIMit:UPPer?

LIMit:UPPer CALCulate:LIMit:UPPer <value> | MIN | MAX sets the upper limit for

limit testing. You can set the value to any number between 0 and ±120% of the highest range, for the present function. MIN = –120% of the highest

MAX = 120% of the highest range. You must turn on the math

range. operation e.g., execute CALC:STAT ON before writing to the math register. The upper limit is stored in volatile memory.

Example Set the upper limit:

CALC:STAT ON Turn on the math operation CALC:LIM:UPP 3000 Set the upper limit.

CALC:FUNC LIM Select the LIMit math operation.

You can select the calculate function at any time before or after enabling the calculate state.

:LIMit:UPPer? CALCulate:LIMit:UPPer? [MIN | MAX] queries the upper limit.

Example Query the upper limit set for the LIMit math operation:

CALC:LIM:UPP? Queries the upper limit.

77 Multimeter Command Reference Chapter 3

CALibration:COUNt? CALibration:LFRequency

CALibration The CALibration command subsystem allows you to enter a security code to

prevent accidental or unauthorized calibrations of the multimeter. When you first receive your multimeter, it is secured. You must unsecure it by entering the correct security code before you can calibrate the multimeter (see CALibration:SECure:STATe OFF|ON <code> command).

Subsystem Syntax CALibration

:COUNt? CALibration:COUNt? queries the multimeter to determine the number of

times a point calibration has occurred. A complete calibration of the multimeter increases the count by the number of points calibrated. It is not a record of complete calibrations. The count is stored in non-volatile memory.

Comments *RST does not change the calibration count stored in non-volatile memory.

Example Querying the number of occurrences of point calibrations:

CAL:COUN? Query the calibration count.

:LFRequency CALibration:LFRequency 50 | 60 | 400 sets the line frequency to either

50 Hz or 60 Hz.

Comments

•

The wrong line frequency setting will cause reading errors to occur.

• You must execute the CAL:LFR command with a parameter of 50 or

400 to change the line frequency setting to 50 Hz. Specifying 400 Hz sets line frequency to 50 Hz since 400 is an even multiple of 50.

Default Setting: 60 Hz

*RST does not change the line frequency setting.

Example Setting the line frequency to 50 Hz:

CAL:LFR 50 Change the line frequency.

Chapter 3 Multimeter Command Reference 78

CALibration:LFRequency? CALibration:SECure:STATe

:LFRequency? CALibration:LFRequency? queries the line frequency setting.

Comments This command returns +50 for line frequency set to 400 because 400 is an

even multiple of 50.

Example Query the line frequency setting:

CAL:LFR? Query the line frequency.

:SECure:CODE CALibration:SECure:CODE <new code> enters a new calibration

security code. To change the security code, first unsecure the multimeter using the old security code with :SEC:STAT OFF, <old code>. Then, enter the new code. The calibration security code may contain up to 12 characters. The security code is stored in non-volatile memory.

Comments

Example Enter a new calibration security code:

:SECure:STATe

•

The security code is set to "HP_E1412" for C-size (or "HP_E1312" for B-size) when the multimeter is shipped from the factory. The security code is stored in non-volatile memory, and does not change when power has been off or after a remote interface reset.

• The security code <new code> can contain up to 12 alphanumeric

characters. The first character must be a letter. The remaining characters can be letters or numbers or an underscore. You do not have to use all 12 characters but the first character must be a letter.

• If you forget or lose the active security code, you can disable the

security feature by adding a jumper inside the multimeter (see Chapter 5 in the Service Manual). You then enter a new code and remove the jumper.

CAL:SEC:STAT OFF, HP_E1412 Unsecure with the old code.

CAL:SEC:CODE

CALibration:SECure:STATe OFF | ON, <

the_new_code

Enter a new calibration code (a maximum of 12 characters).

code

> unsecures or secures

the multimeter for calibration. The calibration code must be the code set by the CAL:SEC:CODE command. The state is stored in non-volatile memory.

Parameters

Parameter Name Parameter Type Range of Values Default Units

OFF|ON boolean OFF | 0 | ON | 1 none

code discrete up to 12 characters

set by :SEC:CODE

none

79 Multimeter Command Reference Chapter 3

CALibration:SECure:STATe? CALibration:STRing?

Comments

•

You can substitute decimal values for the OFF (“0”) and ON (“1”) parameters.

• The multimeter calibration is secured when shipped from the factory.

The security code is set to "HP_E1412" (or "HP_E1312" for B-size).

*RST does not change the state.

Example Set the calibration state to unsecured:

CAL:SEC:STAT OFF, HP_E1412 Unsecure multimeter calibration.

:SECure:STATe? CALibration:SECure:STATe? returns a "1" or "0" to show whether the

calibration security state is enabled (1) or disabled (0). The number is sent to the output buffer.

Example Query the calibra ti o n sec uri t y st ate:

CAL:SEC:STAT? Query multimeter calibration

enter statement Enter value into computer.

security state

:STRing CALibration:STRing <quoted string> allows you to record calibration

information about your multimeter while CAL:SEC:STAT is OFF. For example, you can store information such as the last calibration date and/or the next calibration due date. The calibration message can contain up to 40 characters . Char ac t er s i n ex ce ss of 40 are truncated and no er ro r i s generated. The string is stored in non-volatile memory.

Parameters

Parameter Name Parameter Type Range of Values Default Units

<quoted string> discrete alphanumeric none

•

Comments

The calibration message can contain up to 40 characters.

• Calibration security state must be OFF to store a string.

• The calibration message is stored in non-volatile memory and does

not change when power has been off or after a remote interface reset.

Example Enter calibration information to record the next calibration date:

CAL:STR ’Cal 4/4/YY, Due 10/4/YY’ Enter a calibration message to

record the cal date of April 4 and next cal due date as October 4 (YY = year of due date ) .

:STRing? CALibration:STRing? queries the calibration message and returns a

quoted string (or a null string " " if nothing is present).

Chapter 3 Multimeter Command Reference 80

CALibration:VALue CALibration:ZERO:AUTO

Example Query the calibra ti o n me ss ag e:

CAL:STR? Query the calibration message.

enter statement Enter value into computer.

:VALue CALibration:VALue <cal_value> specifies the value of the known

calibration signal used by the calibration procedure. See the HP E1312A

and HP E1412A Service Manual, Chapter 5 "Adjustments", for a more

detailed description of the multimeter’s calibration/adjustment procedures.

Parameters

Parameter Name Parameter Type Range of Values Default Units

<cal_value> numeric see service manual none

Comment

Example Enter the known value for the calibration source signal:

*RST does not affect the calibration value.

CAL:VAL 10.0 Enter calibration value .

:VALue? CALibration:VALue? queries the present calibration value.

Example Query the calibration value:

CAL:VAL? Query the calibration value.

enter statement Enter value into computer.

:ZERO:AUTO CALibrate:ZERO:AUTO <mode> enables or disables the autozero

mode. Auto zero applies to dc voltage, dc current and 2-wire ohms measurements only. 4-wire ohms and dc voltage ratio measurements automatically enable the autozero mode.

Parameters

Parameter Name Parameter Type Range of Values Default Units

mode boolean OFF | 0 | ON | 1|

ONCE

none

Comments •

You can use "0" for OFF and "1" for ON in the mode parameter.

• The ON parameter enables autozero. This is the default parameter

which causes the multimeter to internally disconnect the input signal following each measurement and make a zero measurement. The zero reading is subtracted from the input signal reading to prevent

offset voltages present on the multimeter’s input circuitry from affecting measurement accuracy.

81 Multimeter Command Reference Chapter 3

CALibration:ZERO:AUTO? CALibration:ZERO:AUTO?

• The OFF parameter disables autozero. In this mode the multimeter

takes one zero measurement and subtracts it from all subsequent input signal measurements prior to a change in function, range or integration time. A new zero measurement is made following a change in function, range or integration time. This mode increases measurement speed because a zero measurement is not made for each input signal measurement.

• Autozero ONCE issues an immediate zero measurement and can be

used to get an update on the zero measurement for a specific input signal measurement. This helps to increase measurement speed since you update the zero reading without making zero measurements for every measurement.

• *RST Condition: CALibrate:ZERO:AUTO ON (autozero enabled)

:ZERO:AUTO? CALibrate:ZERO:AUTO? queries the autozero mode. Returns "0" (OFF

or ONCE) or "1" ON.

Chapter 3 Multimeter Command Reference 82

CALibration? CALibration?

CALibration? CALibration? performs a calibration using the specified calibration value

set by the CALibration:VALue command and queries the calibration response to ve ri f y a su cc es sf ul ca li br at i o n.

Comments

•

Execution of this command begins the electronic adjustment for the function and range the multimeter is set to. The adjustment is performed based on the value stated in the CAL:VAL command and the multimeter expects that value at the input terminals.

• The command returns "0" to indicate there are no calibration errors

and the calibration was performed. A "1" is returned if a calibration error occurs and a calibration is unable to be performed. The error message is reported to the output buffer.

• Yo u must set CALibration:SECu re:STAT e OFF <code> to allow a

calibration to be performed. This requires that you know the calibration secure code. The secure state enabled pr events unauthorized calibration of the multimeter.

Calibrate the active function and range using the CAL:VALue:

CAL? Perform the calibration.

monitor the status byte to detect calibration operation complete enter statement Enter cal response into computer

to verify the calibration was successful.

83 Multimeter Command Reference Chapter 3

CONFigure CONFigure

CONFigure The CONFigure command subsystem configures the multimeter to perform

the specified measurement with the given range and resolution. CONFigure does not make the measurement after setting the configuration. Executing CONFigure is equivalent to setting the multimeter configuration as follows:

Command Setting

RANGe As specifie d (or AUTO).

RESolution As specified, or as a function of range, integration

time, or NPLCs .

AC filter ([SENSe:]DET:BAND)

Autozero ([SENSe:]ZERO:AUTO)

Input resistance ([SENSe:]INP:IMP:AUTO)

Samples per trigger (SAMP:COUN) Trigger count (TRIG:COUN) Trigger delay (TRIG:DEL) Trigger source (TRIG:SOUR) VM Complete routing (OUTP:TTLT<n>:STAT)

Math function (CALCulate:STATe)

20 Hz - 300 kHz (medium filter)

OFF if resolution setting results in NPLC <1; ON if resolution setting results in NPLC ≥1

Applies to dc voltage and is disabled for all other functions. 10MΩ for all dc voltage ranges.

1 sample 1 trigger AUTO (Automatic delay) IMM (trigger signal is always true) OFF (all trigger lines ; n = 0 - 7)

OFF

After configuring the multimeter, use the INITiate command to place the multimeter in the wait-for-trigger state and store readings in the multi-

meter’s internal memory. Or, use the READ? command to make the measurement and send the readings to the output buffer when the trigger is received.

Subsystem Syntax CONFigure

:CURRent[:DC] [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] :CURRent:AC [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] :FREQuency [< range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] :FRESistance [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] :PERiod [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] :RESistance [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] [:VOLTage[:DC]] [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] [:VOLTage[:DC]]:RATio

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

:VOLTage:AC [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

Chapter 3 Multimeter Command Reference 84

CONFigure:CURRent[:DC] CONFigure:CURRent[:DC]

The CONFigure command RANGe and RESolution parameters are optional. You will get the default range and resolution settings if you do not specify a range or resolution in the command. You will get these default settings even if you set a range or resolution different from the default value prior to executing the CONFigure command. The following table lists the default settings you can expect from the CONFigure command for each function.

Default Settings for CONFigure Command by Function.

FUNCTION RANGE RESOLUTION

CURR[:DC] 1A

CURR:AC 1A

FREQ FREQ:RANG = 3 Hz

FRES

PER PER:RANG = 0.333 sec

RES

VOLT[:DC] 10V

VOLT[:DC]:RAT 10V

VOLT:AC 10V

:CURRent[:DC] CONFigure:CURRent[:DC]

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the DC current function and allows you to specify the measurement range and resolution.

1 µA

10 µA

30 µHz

VOLT:RANG = 10V

1 kΩ 1 mΩ

3.33 µseconds

VOLT:RANG = 10V

1 kΩ 1 mΩ

10 µV 10 µV

100 µV

Parameters

Parameter Name Parameter Type Range of Values Default Units

range numeric 10mA | 100mA | 1 A | 3 A |

MIN | MAX | DEF | AUTO

resolution numeric resolution

| MIN | MAX | DEF

Comments •

To select a standard measurement range, specify range as the input

signal’s maximum expected current. The multimeter then selects the correct range to accept that input.

85 Multimeter Command Reference Chapter 3

CONFigure:CURRent:AC CONFigure:CURRent:AC

• The AUTO option for the range parameter enables autorange and

will not accept a resolution parameter but will default the integration time to 10 PLC.

• The DEFault option for the range parameter will also enable auto-

range. The DEF option for the resolution parameter defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e an d resolution:

For range: MIN = 10 mA; MAX = 3A

For resolution: See Table 1 in this chapter for valid resolution choices for each range.

• To select autorange, specify AUTO or DEF for range or do not

specify a value for the range and resolution parameters (see next bullet comment). In the autorange mode, the multimeter samples the input signa l bef or e ea ch me as ur eme nt an d se l ec t s t he app ro pr i at e range.

• To specify the MIN or MAX resolution while autoranging, you must

specify the AUTO or DEF parameter for range and specify MIN or MAX e.g., CONF:CURR:DC DEF,MIN or CONF:CURR:DC DEF,MAX or CONF:CURR AUTO,MIN or CONF:CURR AUTO,MAX (you cannot omit the range parameter DEF or AUTO). This prevents the MIN or MAX resolution from being interpreted as a range setting.

Example Making DC Current Measurements

CONF:CURR 3,MAX Function: dc current;

SAMP:COUN 3 Take 3 readings; trigger source

READ? Place multimeter in

enter statement Enter readings into computer.

:CURRent:AC CONFigure:CURRent:AC

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the AC current function and allows you to specify the measurement range and resolution. See the range versus resolution table at the beginning of this chapter for valid resolution choices for each ac current range.

range selec t ed: 3A; MAX resolution: 0.3 mA.

is IMMediate by default.

wait-for-trigger state and make measurements; send readings to output buffer.

Chapter 3 Multimeter Command Reference 86

CONFigure:CURRent:AC CONFigure:CURRent:AC

Parameters

Parameter Name Parameter Type Range of Values Default Units

Comments

range numeric 1 A | 3 A |

MIN | MAX | DEF | AUTO

resolution numeric resolution

| MIN | MAX | DEF

•

To select a standard measurement range, specify range as the input

signal’s maximum expected current. The multimeter then selects the correct range that will accept the input.

• T he AUTO or DEFault option for the range parameter enables

autorange.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e an d resolution:

For range: MIN = 1 A; MAX = 3A

For resolution: MIN selects the best resolution (the smallest value) for the selected range. MAX selects the worst resolution (the largest value) for the selected range. See Table 5 in this chapter for resolution choices.

• To select autorange, specify DEF for range or do not specify a value

for the range and resolution parameters (see next bullet comment). In the autorange mode, the multimeter samples the input signal before each measurement and selects the appropriate range.

• T o specify the MIN or MAX resolution while autoranging, you must

specify the AUTO or DEF parameter for range and specify MIN or MAX e.g., CONF:CURR:AC DEF,MIN or CONF:CURR:AC DEF,MAX or CONF:CURR:AC AUTO,MIN or CONF:CURR:AC AUTO,MAX (you cannot omit the range parameter DEF or AUTO). This prevents the MIN or MAX resolution from being interpreted as a range setting.

Example Making AC Current Measurements

CONF:CURR:AC 3,MAX Function: dc current;

SAMP:COUN 3 Take 3 readings; trigger source

READ? Place multimeter in

enter statement Enter readings into computer.

range selec t ed: 3A; MAX resolution: 0.3 mA.

is IMMediate by default.

wait-for-trigger state and make measurements; send readings to output buffer.

87 Multimeter Command Reference Chapter 3

CONFigure:FRESistance CONFigure:FRESistance

:FRESistance CONFigure:FRESistance

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the 4-wire ohms function and allows you to specify the measurement range and resolution.

Parameters

Comments

Parameter

Name

range numeric

resolution numeric resolution

•

To select a standard measurement range, specify range as the input

Parameter

Type

Range of Values Default

100Ω | 1kΩ | 10kΩ | 100kΩ |

1MΩ | 10MΩ | 100MΩ |

MIN | MAX | DEF | AUTO

| MIN | MAX | DEF

Units

ohms

signal’s maximum expected resistance. The multimeter then selects the correct range that will accept the input.

• The AUTO or DEFault option for the range parameter enables

autorange. The DEFault option for resolution defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e an d resolution:

For range: MIN = 100Ω; MAX =100 MΩ

For resolution: MIN selects the best resolution (the smallest value) for the selected range. MAX selects the worst resolution (the largest value) for the selected range.

• To select autorange, specify DEF for range or do not specify a value

for the range and resolution parameters. In the autorange mode, the multimeter samples the input signal before each measurement and selects the appropriate range.

• T o specify a MIN or MAX resolution while autoranging, you must

specify the AUTO or DEFault parameter; CONF:FRES DEF,MIN or CONF:FRES DEF,MAX or CONF:FRES AUTO,MIN or CONF:FRES AUTO,MAX (you cannot omit the range parameter). This prevents the MIN or MAX resolution from being interpreted as a range setting.

• Related Commands: FETCh?, INITiate, READ?

Chapter 3 Multimeter Command Reference 88

CONFigure:RESistance CONFigure:RESistance

Example Making 4-Wire Ohms Measurements

CONF:FRES 1500,MAX Function: 4-wir e ohms;

range selected: 10 kΩ; MAX resolution: 1

SAMP:COUN 3 Take 3 readings; trigger source

is IMMediate by default.

READ? Place multimeter in

wait-for-trigger state and make measurements; send readings to output buffer.

enter statement Enter readings into computer.

Ω

:RESistance CONFigure:RESistance

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]] selects the 2-wire ohms function and allows you to specify the range and resolution.

Parameters

Parameter Name Parameter Type Range of Values Default Units

Comments

range numeric

resolution numeric resolution

•

To select a standard measurement range, specify range as the input

100Ω

| 1kΩ | 10kΩ |100kΩ |

1MΩ | 10MΩ | 100MΩ |

MIN | MAX | DEF | AUTO

| MIN | MAX | DEF

ohms

signal’s maximum expected resistance. The multimeter then selects the correct range that will accept the input.

• The AUTO or DEFault option for the range parameter enables

autorange. The DEFault option for resolution defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e an d resolution:

For range: MIN = 100Ω; MAX =100MΩ

For resolution: MIN selects the best resolution (the smallest value) for the selected range. MAX selects the worst resolution (the largest value) for the selected range.

• To select autorange, specify DEF for range or do not specify a value

for the range and resolution parameters. In the autorange mode, the multimeter samples the input signal before each measurement and selects the appropriate range.

89 Multimeter Command Reference Chapter 3

CONFigure:VOLTage:AC CONFigure:VOLTage:AC

• To specify a MIN or MAX resolution while autoranging, you must

specify AUTO or DEFault for range; CONF:RES DEF,MIN or CONF:RES DEF,MAX or CONF:RES AUTO,MIN or CONF:RES AUTO,MAX (you cannot omit the range parameter). This prevents the MIN or MAX resolution from being interpreted as a range setting.

• Related Commands: FETCh?, INITiate, READ?

Example Making 2-Wire Ohms Measurements

CONF:RES 850,MAX Function: 2- wi r e oh ms;

range selected: 1 kΩ; MAX resolution: 0.1 Ω.

SAMP:COUN 3 Take 3 readings. INIT Place multimeter in

wait-for-trigger state; store readings in internal memory; trigger source is IMMediate by default.

FETC? Place readings in output buffer. enter statement Enter readings into computer.

:VOLTage:AC CONFigure:VOLTage:AC

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the AC-coupled RMS voltage function and allows you to specify the range and resolution.

Parameters

Parameter Name Parameter Type Range of Values Default Units

range numeric 0.1V | 1V | 10V | 100V |

resolution numeric resolution

•

Comments

To select a standard measurement range, specify range as the input

signal’s maximum expected voltage. The multimeter then selects the correct range that will accept the input.

• T he AUTO or DEFault option for the range parameter enables

autorange. The DEFault option for resolution defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e:

volts

300V | MIN | MAX | DEF |

AUTO

volts

| MIN | MAX | DEF

For range: MIN = 0.1V; MAX = 300V.

For resolution: See Table 4 for valid resolution choices for each range.

Chapter 3 Multimeter Command Reference 90

CONFigure[:VOLTage[:DC]] CONFigure[:VOLTage[:DC]]

• To select autorange, specify AUTO or DEF for range or do not

specify a value for the range and resolution parameters. In the autorange mode, the multimeter samples the input signal before each measurement and selects the appropriate range.

• T o specify a MIN or MAX resolution while autoranging, you must

specify AUTO or DEFault for range; CONF:VOLT:AC DEF,MIN or CONF:VOLT:AC DEF,MAX or CONF:VOLT:AC AUTO,MIN or CONF:VOLT:AC AUTO,MAX (you cannot omit the range parameter). This prevents the MIN or MAX resolution from being interpreted as a range setting.

Example Making AC Voltage Measurements

CONF:VOLT:AC 0.54,MAX Function: AC volts;

SAMP:COUN 3 Take 3 readi ng s; source is

READ? Place multimeter in

enter statement Enter readings into computer.

[:VOLTage[:DC]] CONFigure[:VOLTage[:DC]]

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the DC voltage function and allows you to specify the range and resolution.

Parameters

Parameter Name Parameter Type Range of Values Default Units

range numeric 100mV | 1V | 10V | 100V |

range selec t ed: 1A; MAX resolution: 100 µA.

IMMediate by default.

wait-for-trigger state and make measurements; send readings to output buffer.

volts

300V | MIN | MAX | DEF |

AUTO

resolution numeric resolution

Comments •

| MIN | MAX | DEF

To select a standard measurement range, specify range as the input

volts

signal’s maximum expected voltage. The multimeter then selects the correct range to accept the input.

• T he AUTO or DEFault option for the range parameter enables

autorange. The DEFault option for resolution defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

value for range and resolution:

91 Multimeter Command Reference Chapter 3

CONFigure[:VOLTage[:DC]] :RATio CONFigure[:VOLTage[:DC]] :RATio

For range: MIN = 100mV; MAX = 300V.

• To select autorange, specify DEFault for range or do not specify a

value for the range and resolution parameters. In the autorange mode, the multimeter samples the input signal before each measurement and selects the appropriate range.

• T o specify a MIN or MAX resolution while autoranging, you must

specify AUTO or DEFault for range; CONF:VOLT:DC DEF,MIN or CONF:VOLT:DC DEF,MAX or CONF:VOLT:DC AUTO,MIN or CONF:VOLT:DC AUTO,MAX (you cannot omit the range parameter). This prevents the MIN or MAX resolution from being interpreted as a range setting.

• Related Commands: FETCh?, INITiate, READ?

Example Making DC Voltage Measurements

[:VOLTage[:DC]]

:RATio

CONF:VOLT 0.825,MAX Function: DC voltage;

range selec t ed: 1A; MAX resolution: 100 µA.

SAMP:COUN 3 Take 3 readi ng s. INIT Place multimeter in

FETC? Place readings in output buffer. enter statement Enter readings into computer.

wait-for-trigger state; store readings in internal memory; trigger source is IMMediate by default.

CONFigure[:VOLTage[:DC]]:RATio [<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

configures the multimeter for dc:dc ratio measurements with the specified range and resolution.

DC:DC RATIO =

dc signal voltage

dc reference voltage

and LO input

Sense HI

and LO input

The ratio is calculated from the voltage applied to the HI and LO input terminals divided by the reference voltage applied to the "Sense" HI and LO terminals. Autoranging is automatically selected for the reference voltage measurement on the "Sense" HI and LO terminals. The specified range in the command applies to the signal connected to the HI and LO input terminals.

Chapter 3 Multimeter Command Reference 92

CONFigure:FREQuency CONFigure:FREQuency

NOTE

Parameters

Comments

Autorange on the "Sense" terminals is from 100 mV to 10V range only. Maximum voltage you can apply to the "Sense" terminals is 10V.

Parameter Name Parameter Type Range of Values Default Units

range

(HI-LO input)

resolution numeric resolution

•

To select a standard measurement range, specify range as the input

numeric 100mV | 1V | 10V | 100V |

300V | MIN | MAX | DEF |

AUTO

| MIN | MAX | DEF

volts

signal’s maximum expected voltage. The multimeter then selects the correct range to accept the input.

• T he AUTO or DEFault option for the range parameter enables

autorange. The DEFault option for resolution defaults the integration time to 10 PLC.

• The MIN and MAX parameters select the minimum or maximum

values for ra ng e an d resolution:

For range: MIN = 100mV; MAX = 300V.

For resolution: MIN selects the best resolution (the smallest value) for the selected range. MAX selects the worst resolution (the largest value) for the selected range.

:FREQuency CONFigure:FREQuency

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the frequency function.

Parameters

Parameter Name Parameter Type Range of Values Default Units

range numeric 3E+00 Hz

resolution numeric 3E-04 | 3E-05 | 3E-06 Hz

Comments •

The frequency function uses one "range" for all inputs between 3 Hz and 300 kHz. A frequency measurement returns "0" if no input is applied.

93 Multimeter Command Reference Chapter 3

CONFigure:PERiod CONFigure:PERiod

• Range and resolution settings are listed below for the MIN, MAX,

DEF and AUTO parameters and the settings after a module reset (*RST).

PARAMETER RANGE RESOL UTI ON

MIN 3E+00 3E-06

MAX 3E+00 3E-04

DEF | AUTO and

module reset (*RST)

:PERiod CONFigure:PERiod

[<range>|MIN|MAX|DEF|AUTO[,<resolution>|MIN|MAX|DEF]]

selects the period function and allows you to specify range and resolution.

Parameters

Parameter Name Parameter Type Range of Values Default Units

range numeric 3.3E-01 Sec

resolution numeric 3.3E-05 | 3.3E-06 | 3.3E-07 Sec

•

Comments

The period function uses one "range" for all inputs between 0.33 seconds and 3.3 µSec. A period measurement will return "0" if no

input is applied.

• Range and resolution settings are listed below for the MIN, MAX,

DEF and AUTO parameters and the settings after a module reset (*RST).

3E+00 3E-05

PARAMETER RANGE RESOL UTI ON

MIN 3.33E-01 3.33E-07

MAX 3.33E-01 3.33E-05

DEF | AUTO and

module reset (*RST)

3.33E-01 3.33E-06

Chapter 3 Multimeter Command Reference 94

CONFigure? CONFigure?

CONFigure? The CONFigure? command queries the multimeter to return the

configuration set by the most recent CONFigure or MEASure command. It returns a quoted string to the output buffer in the following format:

“<function> <parameter>,<parameter>”

Subsystem Syntax CONFigure?

Comments

When the multimeter is configured for current, voltage or resistance measurements, CONFigure? returns the function followed by the selected range and resolution. For example:

“CURR:AC +1.000000E+00,1.000000E-05” “CURR +1.000000E+00,1.000000E-05” “VOLT:AC +2.000000E+02,1.000000E-06” “VOLT +3.000000E+02,1.000000E-06” “FRES +100.0000E+03,1.000000E-05” “RES +1.000000E+03,1.000000E-03” "FREQ +3.000000+00,3.000000E-05" "PER +3.333330E-01,3.333330E-06"

If you specify DEF, MIN, or MAX for the range or resolution parameters in CONFigure or MEASure, the CONFigure? command returns the selected value.

Related Commands: CONFigure, MEASure

Example Querying the Multimeter Configuration

dimension string array Dimension computer array to

store string.

CONF:FRES 900,MAX Function: 4-wir e oh ms;

range selected: 1kΩ; MAX resolution: 100 mΩ.

CONF? Query confi guration. enter statement Enter string into computer .

String Returned:

“FRES +1.000000E+003,9.999999E-02”

95 Multimeter Command Reference Chapter 3

DATA:POINts? DATA:POINts?

DATA The multimeter can store up to 512 readings in internal memory. The

DATA command allows you to determine how many readings are currently stored.

Subsystem Syntax DATA

:POINts?

:POINts? The INITiate command uses internal memory to store readings prior to a

FETCh? command e.g., when a measurement is initiated by the INITiate command. You can query the number of stored readings in memory by sending the DATA:POINts? command.

Comments

•

INITiate command uses internal memory to store readings prior to using a FETCh? command. You use the DATA:POINts? command to query the number of readings stored in internal memory to determine the amount of data space to allocate on your computer to receive the data.

Chapter 3 Multimeter Command Reference 96

FETCh? FETCh?

FETCh? The FETCh? command retrieves measurements stored in the module’s

internal memory by the most recent INITiate command and places them in the output buffer. This command is most commonly used with CONFigure.

Subsystem Syntax FETCh?

Comments

•

Execute INITiate before sending the FETCh? command to place the multimeter in the wait-for-trigger state. If the multimeter has not taken any data (i.e., if INITiate has not been executed), or if settings have been altered since the last FETCh? (i.e., changing function or range), the “Data corrupt or stale” error will be generated.

NOTE: If you don’t alter settings, you could "FETCh?" the same data over and over again without error.

• Readings sent to the output buffer can consist of two different

lengths (bytes or characters) in Real ASCII format:

±1.23456E±12 LF or ±1.234567E±12

• Each measurement is terminated with a Line Feed (LF). The HP-IB

±1.23456E±12 LF,±1.234567E±12 LF,±1.23456E±12 LF EOI

• The Multimeter’s internal memory stores 512 readings maximum.

• Related Commands: CONFigure, INITiate, READ?

• *RST Condition: Executing FETCh? after a *RST generates error

“Data corrupt or stale” (*RST places the multimeter in the idle state).

Example Transferring Stored Readings to Output Buffer

dimension array Dimension computer array

to store 100 readings.

CONF:VOLT:DC Function: DC voltage. SAMP:COUN 100 100 readi ngs per trigger. INIT Store readings in internal

memory; trig ger source is IMMediate by default.

FETC? Place readings in output buffer. enter statement Enter readings into computer.

97 Multimeter Command Reference Chapter 3

INITiate[:IMMediate] INITiate[:IMMediate]

INITiate The INITiate command subsystem places the multimeter in the

wait-for-trigger state. This command is most commonly used with CONFigure. See the section titled "Triggering the Multimeter" in Chapter 2 for a complete description of the HP E1312A and HP E1412 trigger system which discusses the wait-for-trigger state.

Subsystem Syntax INITiate

[:IMMediate]

[:IMMediate] INITiate[:IMMediate] places the multimeter in the wait-for-trigger state.

When a trigger is received, readings are placed in multimeter internal memory.

Comments

•

After the trigger system is initiated using INITiate, use the TRIGger command subsystem to control the behavior of the trigger system.

• I f TRI Gge r: SOU Rc e i s IM Me dia t e, th e mea su re men t st art s an d

readings are stored in internal memory as soon as INITiate is executed. Readings stored in memory from previous commands are replaced by the new readings.

• To transfer readings from memory to the output buffer, use the

FETCh? command.

• If TRIGger:SOURce is not IMMediate, the measurement starts as

soon as a trigger is received either from the external BNC connector, the VXIbus backplane (TTLT<n> trigger lines) or a BUS trigger.

• The READ? command executes INITiate implicitly. The MEASure

command executes READ? implicitly. Executing READ? outputs

data directly to the output buffer, bypassing the multimeter’s internal memory.

• Related Commands: CONFigure, FETCh?, READ?

• *RST Condition: *RST places the multimeter in the idle state.

Example Placing Multimeter in Wait-For-Trigger State

CONF:VOLT:DC Function: DC voltage. TRIG:SOUR EXT Trigger source is the external

INIT Place multimeter in

FETC? Place readings in output buffer.

INIT You must re-initiate the

BNC on the multimeter .

wait-for-trigger state; store readings in internal memory when ext trigger is received.

wait-for-trigger state after each trigger cycle.

Chapter 3 Multimeter Command Reference 98

INPut:IMPedance:AUTO INPut:IMPedance:AUTO

INPut The INPut command enables or disables the automatic input impedance

mode for DC voltage measurements.

Subsystem Syntax INPut

:IMPedance:AUTO OFF|ON :IMPedance:AUTO?

:IMPedance:AUTO INPut:IMPedance:AUTO <mode> enables or disables the automatic

input impedance mode for DC voltage measurements. When disabled (AUTO OFF), the multimeter maintains its input impedance of 10 MΩ for

all DC voltage ranges. This is useful to prevent a change in input impedance, caused by changing ranges, from affecting the measurements.

Parameters

Parameter Name Parameter Type Range of V alues Default Units

mode boolean OFF | 0 | ON | 1 none

Example

Comments

mode

(Impedance)

Range

for impedance

AUTO OFF

(10 MΩ)

All ranges 100 mV, 1V and

AUTO ON

(>10 GΩ)

10V (other ranges

are at 10 MΩ)

Enable Automatic Input Impedance (use >10 GΩ for 100 mV, 1V and 10V ranges).

INP:IMP:AUTO ON Enable automatic input

impedance

You can substitute decimal values for the OFF ("0") and ON ("1") parameters.

*RST Conditions: INP:IMP:AUTO OFF

99 Multimeter Command Reference Chapter 3

INPut:IMPedance:AUTO? INPut:IMPedance:AUTO?

:IMPedance:AUTO? INPut:IMPedance:AUTO? returns a number to show whether the

automatic input impedance mode is enabled or disabled: "1" = ON, "0" = OFF. The number is sent to the output buffer.

Example Querying the input impedance mode.

INP:IMP:AUTO ON Enable automatic input

impedance

INP:IMP:AUTO? Query multimeter to return input

impedance mode ("1 ")

enter statement

Enter value into computer

Chapter 3 Multimeter Command Reference 100

Agilent E1312A Users Guide

Specifications and Main Features

Frequently Asked Questions

User Manual