Agilent Technologies 3458A User Manual

274 Chapter 7 BASIC Language for the 3458A
depends on the individual sizes of the subprograms. A typical subprogram
containing 10 commands (including the SUB and SUBEND commands)
might average about 600 bytes. Refer to chapter 3 for more information on
memory usage.
Can I Nest Subprograms?
Yes! Nesting subprograms is the ability to have one subprogram call
(execute) another subprogram. You can nest up to 10 subprograms.
Writing and Loading Subprograms
The subprogram example programs in this section illustrate relatively simple
3458A operations which you can copy and use in more complex mainline
programs of your own design. This section also shows how to create and edit
subprograms.
Note PROGRAMMING HINT
You should execute the SCRATCH command and download the
subprograms from your system controller at the beginning of your test
system program. This helps memory management for the 3458A and
ensures that the subprograms are downloaded and ready when they are
needed.
Executing the SUB command instructs the 3458A to store all subsequent
commands, until the SUBEND command, in the specified subprogram.
Subprogram names may contain up to 10 characters. The first character must
be a letter (A–Z) but the remaining nine characters can be letters, numbers
(0–9), the underscore character ("_"), or the question mark ("?"). Subprogram
names must not be the same as 3458A commands or parameters, previously
defined array or variable names, or stored state names.
The following program shows how to create a simple subprogram which
configures the multimeter to make three dc voltage measurements.
10 OUTPUT 722; "SUB DMM_CONF"
20 OUTPUT 722; "DCV8,0.00125"
30 OUTPUT 722; "NRDGS 3"
40 OUTPUT 722; "TRIG SGL"
50 OUTPUT 722; "SUBEND"
60 END
The two statements SUB DMM_CONF and SUBEND along with the three
commands on line 20, 30, and 40 form the subprogram named DMM_CONF.
When a subprogram is entered, the 3458A checks for syntax errors just like
any other commands. If the syntax is not correct, an error is generated and
the command is not stored in the subprogram. You must then edit your
subprogram in the system controller and download it again. The 3458A stores
the subprogram in non-volatile memory. You can then execute the
subprogram from either the front-panel keyboard or the system controller.

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