Agilent Technologies 3458A User Manual

48 Chapter 3 Configuring for Measurements
annunciator illuminates.
Reading the Error
Registers
When a hardware error is detected, the multimeter sets a bit in the auxiliary,
error register and also sets bit 0 in the error register.When a programming
error is detected, the multimeter sets a bit in the error register only.
The ERRSTR? command reads each error (one error at a time) and then clears
the corresponding bit. If one or more bits are set in the auxiliary error register,
the ERRSTR? command reads that register first before proceeding to the
error register. The ERRSTR? command returns two responses. The first
response is the decimal: value of the least significant (lowest numbered) set
bit. The second response is a message (string) explaining the error (the
maximum string length returned is 200 characters). After reading a bit, the
ERRSTR? command clears that bit.
The following program uses the ERRSTR? command to read all errors, one
error at a time. After all set bits have been read and cleared, or if there were
no set bits in either register, the ERRSTR? command returns 0, "NO
ERROR".
10 OPTION BASE 1
!COMPUTER ARRAY NUMBERING
STARTS WITH 1
20 DIM A$[200]
!DIMENSION STRING VARIABLE
30 OUTPUT 722; "ERRSTR?"
!READS ERROR MESSAGE
40 ENTER 722; A,A$
!ENTERS NUMERIC INTO A,
STRING INTO A$
50 PRINT A,A$
!PRINTS RESPONSES
60 IF A>0 THEN GOTO 30
!LOOP TO READ EACH ERROR
70 END
The ERR? and AUXERR? commands return the decimal sum of all set bits
in the error register and the auxiliary error register, respectively. Refer to
these commands in Chapter 6 for example programs and listings of the
possible errors.
Calibration The multimeter has two forms of calibration: external calibration and
autocalibration. The external calibration involves a procedure using external
reference sources. Refer to the 3458 Calibration Manual for more
information on the external calibration.
The CALNUM? query command returns a number indicating the number of
times the multimeter has been externally calibrated. By routinely checking
this number, you can monitor the calibrations performed on the multimeter.
The following program reads and returns the present calibration number.
10 OUTPUT 722;"CALNUM?"
20 ENTER 722;A
30 PRINT A
40 END
Autocalibration The multimeter has four autocalibration (autocal) routines: DCV, AC,
OHMS, and ALL. These routines improve short-term accuracy for many or
all measurement functions, but are not substitutes for periodic external
calibration of the multimeter. The measurement functions affected by each

Agilent Technologies 3458A Specifications

General

Model	3458A
Manufacturer	Agilent Technologies
Category	Multimeter
Digits	8.5
Sampling Rate	100, 000 readings/second
Interface	GPIB

Summary

Safety Symbols and Warnings

General Safety Precautions (WARNINGS)

Outlines essential safety precautions for operating, servicing, and repairing the product to prevent injury or damage.

Chapter 2 Getting Started

Operating from the Front Panel

Covers using front panel keys, making measurements, changing functions, and controlling display settings.

Operating from Remote

Explains how to control the multimeter remotely via GPIB, including address management and command sending.

Chapter 3 Configuring for Measurements

General Configuration

Configuring for DC or Resistance Measurements

Details how to configure the multimeter for DC voltage, DC current, and 2-wire or 4-wire resistance measurements.

Configuring for AC Measurements

Explains how to configure the multimeter for AC voltage, AC current, frequency, or period measurements.

Chapter 4 Making Measurements

Triggering Measurements

Explains the three-event triggering hierarchy (arm, trigger, sample) and various event choices.

Using Reading Memory

Sending Readings Across the Bus

Increasing the Reading Rate

Discusses the multimeter's high-speed mode and factors affecting reading rate and transfer speed.

Math Operations

Explains real-time and post-process math operations, enabling/disabling them, and math registers.

Chapter 5 Digitizing

Digitizing Methods

Details DCV, Direct-Sampling, and Sub-sampling methods, summarizing their characteristics and signal paths.

The Sampling Rate

Level Triggering

Describes how to specify voltage and slope for sampling initiation, with examples for DCV and direct-sampling.

DCV Digitizing

Direct-Sampling

Explains direct-sampling using track-and-hold, its bandwidth, and specifying ranges via max._input parameter.

Sub-Sampling

Covers sub-sampling fundamentals, advantages, and how to specify effective interval and number of samples.

Chapter 6 Command Reference

ACAL

Instructs the multimeter to perform self-calibrations (ALL, DCV, AC, OHMS) and discusses autocalibration security.

NRDGS

OFORMAT

PRESET

Configures the multimeter to one of three predefined states: NORM, FAST, or DIG for different operation modes.

SUB

Stores a series of commands as a subprogram, assigning a name for later execution.

TARM

Defines the trigger arm event to enable the trigger event and can be used for multiple measurement cycles.

TEST

Causes the multimeter to perform a series of internal self-tests to check hardware and software integrity.

TRIG

Specifies the trigger event that initiates a measurement, working with TARM and NRDGS.

Chapter 7 BASIC Language for the 3458A

BASIC Language Commands

Subprograms

Explains how to store, execute, and manage BASIC language subprograms for system control and automation.

Appendix B GPIB Commands

TRIGGER (GET)

Appendix C Procedure to Lock Out Front/Rear Terminals and Guard Terminal Switches

Procedure

Outlines the steps for installing the switch lockout kit, including covers and pushrod removal.

Appendix D Optimizing Throughout and Reading Rate

Maximizing the Testing Speed

Covers strategies like tailoring communication paths, program memory, and state storage for optimal testing speed.

DC Volts, DC Current and Resistance

Explains the measurement paths (DCV, track-and-hold) and trade-offs for DC measurements.

AC Volts and AC Current

Details the three ACV measurement techniques (Analog, Synchronous, Random) and their trade-offs.

Frequency and Period

Optimizing the Testing Process Through Task Allocation

Discusses allocating tasks between the DMM and computer using math functions, memory, and program structure.

Math Operations

State Storage and Program Memory

A Benchmark

Appendix E High Resolution Digitizing With the 3458A

Speed with Resolution

Details the multimeter's flexibility in speed and resolution for audio frequency bandwidth.

Digitizing Analog Signals

Avoiding Aliasing

Provides methods to avoid signal distortion caused by aliasing, ensuring accurate waveform representation.

Choice of Two Measurement Paths

Describes the standard DCV path and the track-and-hold path for digitizing and sampling.

Capturing the Data

High Speed Data Transfers

Errors in Measurements