Agilent Technologies 3458A User Manual

Chapter 6 Command Reference 249
SWEEP
sample to the next. For sub-sampling, the valid range of this parameter is 10E-9
to 6000 seconds with 10ns increments; for all other measurement functions the
range is ( l/maximum reading rate) to 6000 seconds in 100ns increments.
Power-on effective_interval = 100E-9
Default effective_interval = 20µs
#_samples
Specifies the number of samples to be taken. The valid range for this parameter
is 1 to 1.67E+7.
Power-on #_samples = 1024
Default #_samples = 1024
Remarks • The minimum effective interval for DC voltage measurements is 10µs; for
direct-sampling, 20µs; for sub-sampling, 10 nanoseconds.
• The SWEEP command can be used to replace the NRDGS n,TIMER command
and the TIMER command. The SWEEP and NRDGS are interchangeable; the
multimeter uses whichever command was executed last in the programming.
Executing the SWEEP command automatically sets the sample event to TIMER.
In the power-on, RESET, or PRESET state, the multimeter uses the NRDGS
command. The power-on values for SWEEP can only be used for sub-sampling
(since NRDGS does not apply to sub-sampling).
• You cannot use the SWEEP or TIMER functions for AC or AC+DC voltage
measurements using the synchronous or random methods (SETACV SYNC or
RNDM) or for frequency or period measurements.
• When using the SWEEP command (or TIMER event), autoranging is suspended
(typically you should select a fixed range when using SWEEP).
• Query Command. The SWEEP? query command returns two responses
separated by a comma. The first response is the specified effective_interval. The
second response is the specified #_samples. Refer to "Query Commands" near
the front of this chapter for more information.
• Related Commands: FUNC, NRDGS, TIMER
Example In the program on the following page, the SSAC command is used to digitize a
10 kHz signal with a peak value of 5V. The SWEEP command instructs the
multimeter to take 1000 samples (Num_samples variable) with a 2µs
effective_interval (Eff_int variable}. The measurement uses the default level
triggering for the sync source event (trigger from input signal, 0%, AC-coupling,
positive slope).
Line 120 generates a SYN event and transfers the samples directly to the computer.
Lines 240 through 410 sort the sub-sampled data to produce the composite
waveform. The composite waveform is stored in the Wave_form array.
10 OPTION BASE 1 !COMPUTER ARRAY NUMBERING STARTS AT 1
20 INTEGER Num_samples,Inc,I,J,K,L!DECLARE VARIABLES

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