Agilent Technologies 3458A User Manual

Chapter 7 BASIC Language for the 3458A 269
the maximum array size is determined by available 3458A memory
(approximately 10 kbytes if no stored states or subprograms are stored). A
non-integer subscript is rounded to the nearest integer.
Arrays may be resized by re-declaring them. This initializes each element in
the array to a value of zero. You cannot, however, redefine the type of array
(real or integer) without scratching memory first (refer to the SCRATCH
command in chapter 6). Array elements may be used in the same ways simple
variables are used.
Filling Arrays Array elements are initialized to zero when they are declared (DIM, REAL,
or INTEGER commands) or are re-sized. Once you have dimensioned an
array, use the FILL command to load your values into the array. The FILL
command has the following syntax:
FILL array_name, list
The following program fills an integer array with integer values.
10 OUTPUT 722; "INTEGER LIST(9)"
20 OUTPUT722; "FILL LIST 0,100,200,300,400,500,600,700,800,900"
30 END
Note Use the FILL command carefully. It does not work if power is cycled. The
command is effectively deleted from the subprogram at this time. Use
separate LET statements for each value assigned.
Array Size The SIZE? query command returns the number of elements in the specified
array. This number is one more than the index of the last element in the array
due to the option base 0 convention used by the 3458A. Thus, if you
dimension a 10-element array (e.g., DIM LIST(9) ), the SIZE? command will
return "10".
The following program defines an integer array with 10 elements and then
verifies the array size using the SIZE? command.
10 OUTPUT 722; "INTEGER IARRAY(9)"
20 OUTPUT 722; "SIZE? IARRAY"
30 ENTER 722; A
40 PRINT A
50 END
Purging Arrays and
Variables
All variables and arrays are stored in 3458A volatile memory. If the 3458A
loses power, all variables and arrays are lost. The SCRATCH command also
purges all variables, arrays, subprograms, and stored state names (stored
states are explained in chapter 3).
General Purpose Math
You can use general purpose math expressions, following standard BASIC
language conventions, from either the front-panel keyboard, the system
controller, or within 3458A subprograms. The standard math operators,

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