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
Copyright © 1996 Hewlett-Packard Company. All Rights Reserved.
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.
or
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
You can help us improve our manuals by shar ing your comments and suggestions. In appreciation of your time, we will
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Please list the system controller, operating system, programming language, and plug-in modules you are using.
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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
1
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
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.
1
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
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
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
40
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
10
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
Ω
Ω
Ω
Ω
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
9
insulators (10
13
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)
2
Chapter 2 HP E1312A/E1412 A M ultimeter Application Informat ion 30
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