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Fluke 8842A User Manual

Fluke 8842A
269 pages
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®
8842A
Digital Multimeter
Instruction Manual
PN 879309
Date December 1991
Rev.3 7/96
© 1999 Fluke Corporation, All rights reserved. Printed in USA
All product names are trademarks of their respective companies.

Table of Contents

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Fluke 8842A Specifications

General IconGeneral
Maximum Voltage1000 V
Maximum Current2 A
Operating Temperature0°C to 50°C
Weight2.5 kg
DC Voltage Range100mV to 1000V
DC Current Range0 to 2 A
AC Current Range0 to 2 A
Frequency Range20 Hz to 20kHz
Basic Resistance Accuracy0.01%
Dimensions216mm x 88mm x 280mm
Resistance Range200 Ω to 20 MΩ

Summary

Introduction and Specifications

Introduction

Manual provides operating instructions and service info for the 8842A.

The 8842A Digital Multimeter

Describes the 8842A as a high-performance 5-1/2 digit instrument.

Options and Accessories

Lists available options like IEEE-488 and True RMS AC, and accessories.

Specifications

Details input characteristics and accuracy for DC Voltage, AC Voltage, Current, Resistance.

Operating Instructions

Installation

Covers installing the power-line fuse and connecting to line power.

Adjusting the Handle

Instructions for adjusting the handle for optimal viewing angles.

Rack Mounting Kits

Details how to mount the 8842A in a standard 19-inch rack.

Operating Features

Covers power-up features and front/rear panel controls.

Error Messages

Explains how error messages are displayed and lists error codes.

Diagnostic Self-Tests

Details the instrument's self-tests for digital and analog circuitry.

Ranging

Explains selection between autorange and manual range.

Triggering

How triggering executes a measurement cycle and the two modes.

Reading Rates and Noise Rejection

Optimizing measurement speed vs. noise rejection.

Making Measurements

General section on taking measurements.

Input Overload Protection Limits

Limits to avoid applying potentials that exceed overload limits.

Offset Measurements

Using the OFFSET feature to store a reading as a relative reference.

External Cleaning

Cleaning the instrument case.

Remote Programming

Introduction

Section contains programming instructions for use with the IEEE-488 Interface (Option -05).

Capabilities

Lists capabilities of the IEEE-488 Interface, like remote control and programmability.

Bus Set-Up Procedure

Steps to set up the 8842A on the IEEE-488 bus.

Device-Dependent Command Set

Details commands corresponding to front panel controls and functions.

Get Commands

Get commands retrieve instrument information and status.

Put Commands

Put commands set up configuration and operating modes by entering registers.

Input Syntax

Describes how to construct command groups and processes input commands.

Output Data

Describes data loaded into the output buffer and sent to the IEEE-488 bus.

Service Requests

How bus instruments get attention from the controller via SRQ line.

Interface Messages

Categories of interface messages (address, universal, addressed).

Talk-Only Mode

Lets 8842A operate remotely without a controller.

Remote Calibration

Calibrating the 8842A remotely via IEEE-488.

Example Programs

Example programs for 8842A using various controllers.

Measurement Tutorial

Introduction

Section discusses considerations and techniques for effective 8842A use and error sources.

DC Voltage Measurement

Discusses sources of error in DC voltage measurements: circuit loading and input bias current.

Resistance Measurement

Explains measuring resistance in 2-wire and 4-wire configurations.

Applications of the Ohms Functions

Discusses uses of 2-wire and 4-wire ohms functions beyond basic measurement.

A Precision Current Source

Describes the ohms current source as a troubleshooting tool and for meter testing.

DC Current Measurement

Discusses burden voltage error in DC current measurements.

Reducing Thermal Voltages

Techniques for minimizing errors from thermal voltages.

AC Voltage and Current Measurement

Considerations for AC measurements including rms, crest factor, bandwidth.

Crest Factor

Explains crest factor and its importance for waveform measurement.

AC-Coupled AC Measurements

Advantages of AC coupling for measurements.

Combined AC and DC Measurements

How to evaluate total RMS value of waveforms with AC and DC components.

Zero-Input VAC Error

Explains non-zero readings when VAC input terminals are shorted.

Making Accurate Measurements on the 20 mV and 20Ω Ranges

Practices for accurate low-level measurements, minimizing noise and errors.

Making Accurate High-Resistance Measurements

Techniques to minimize leakage and noise in high-resistance measurements.

Theory of Operation

Introduction

Section presents overall functional and detailed circuit descriptions.

Overall Functional Description

Provides a block diagram of the 8842A signal path and main functions.

Detailed Circuit Description

Details circuits for DC Scaling, T/H, Digital Controller, Power Supply, etc.

DC Scaling

Explains scaling for DC inputs and input protection/filtering.

Track/Hold Circuit

Explains the Track/Hold circuit's function and components.

Precision Voltage Reference

Describes the precision voltage reference providing stable reference voltages.

Ohms Current Source

Explains the Ohms Current Source providing precise test current.

Ohms Protection

Details OHMS Protection circuit for input overvoltage and transients.

A/D Converter

Explains the Analog-to-Digital converter and its technique.

Digital Controller

Overview of the Digital Controller's components and function.

Power Supply

Details the power supply circuit providing various voltage outputs.

IEEE-488 Interface (Option -05)

Explains the IEEE-488 Interface block diagram and components.

True RMS AC (Option -09)

Explains the True RMS AC circuit's scaling and conversion functions.

Static Awareness

Handling and Storage Precautions

Practices to minimize damage to static-sensitive devices during handling.

Workstation and Tool Safety

Guidelines for safe handling using anti-static workstations and tools.

Maintenance

Introduction

Section covers performance test, calibration, troubleshooting, and service info.

Performance Test

Compares instrument performance to specifications; recommended post-calibration.

Diagnostic Self-Tests

Checks analog and digital circuitry, including memory and display tests.

DC Voltage Test

Procedure to verify accuracy of the VDC function.

AC Voltage Test (Option -09 Only)

Procedure to verify accuracy of the VAC function for Option -09.

Resistance Test

Procedure to verify accuracy of 2-wire and 4-wire ohms functions.

DC Current Test

Procedure to test the mA DC function accuracy.

AC Current Test (Option -09 Only)

Procedure to test the mA AC function for Option -09.

Calibration

Covers basic, offset/gain, and HF AC calibration procedures.

Erasing Calibration Memory

Procedure to erase calibration memory.

Remote Calibration

Calibrating the 8842A remotely via IEEE-488.

Remote Erasure

Remotely erasing the entire calibration memory.

Disassembly Procedure

Procedures for disassembling the instrument.

Reassembly Procedure

Steps to reassemble the instrument after disassembly.

Internal Fuse Replacement

Procedure for replacing the internal fuse.

Troubleshooting

General approach to troubleshooting and available tools.

Digital Controller Troubleshooting

Troubleshooting the digital controller and its subsystems.

DC Scaling Troubleshooting

Troubleshooting steps for the DC Scaling circuit.

Track/Hold Troubleshooting

Troubleshooting steps for the Track/Hold circuit.

Ohms Current Source Troubleshooting

Troubleshooting steps for the Ohms Current Source.

Precision Voltage Reference Troubleshooting

Troubleshooting steps for the Precision Voltage Reference.

A/D Converter Troubleshooting

Troubleshooting steps for the A/D Converter.

Power Supply Troubleshooting

Troubleshooting steps for the power supply.

IEEE-488 Interface Troubleshooting (Option -05)

Troubleshooting the IEEE-488 Interface.

Diagnostic Program

Using the diagnostic program for troubleshooting the IEEE-488 Interface.

True RMS AC Troubleshooting (Option -09)

Troubleshooting the True RMS AC Option.

Guard Crossing Troubleshooting

Troubleshooting the Guard Crossing circuit.

Internal Cleaning

Precautions for internal cleaning of the instrument.

List of Replaceable Parts

Introduction

Section contains an illustrated list of replaceable parts for the 8842A.

How to Obtain Parts

Information on ordering electrical components directly from the manufacturer or representatives.

Service Centers

Location of authorized service centers.

Options and Accessories

Introduction

Summarizes available options and accessories enhancing 8842A capabilities.

Accessories

Lists and describes various accessories like rack kits, cables, probes, and leads.

Rack-Mount Kits

Details how to mount the 8842A in standard 19-inch rack panels.

Shielded IEEE-488 Interface Cables

Describes available shielded IEEE-488 cables in various lengths.

Replacement Test Leads

TL70A replacement test leads feature safety-designed input connectors.

Deluxe Test Lead Kits

Includes test-tip probes, alligator clips, spade lug tips, and hook tip.

Slim-Flex Test Leads

Adjustable, flexible leads for fitting into small places.

Temperature Probes

Universal probes for temperature measurement and conversion.

RF Probes

Probes for measuring radio frequency AC signals.

Current Shunt

Extends AC or DC current measurement range up to 10A continuous.

Current Probes

Extend AC and DC current measurement range using Hall effect or transformer.

High Voltage Probes

Extend DC and AC voltage measurement range, minimizing shock hazard.

Option -05 IEEE-488 Interface

Introduction

Introduces the IEEE-488 Interface option for programmable instrument use.

Capabilities

Lists the capabilities of the IEEE-488 Interface, including remote control.

External Controls

Describes rear panel EXT TRIG and SAMPLE COMPLETE connectors.

Installation

Provides step-by-step instructions for installing the IEEE-488 PCA.

Programming Instructions

Presents programming instructions and IEEE-488 bus setup.

Maintenance

Service information for the IEEE-488 Interface is in Section 6.

List of Replaceable Parts

List of replaceable parts for the IEEE-488 Interface PCA.

Option -09 True RMS AC

Introduction

Introduces the True RMS AC option for AC voltage and current measurements.

Installation

Provides step-by-step instructions for installing the True RMS AC PCA.

Operating Instructions

Refers to Section 2 for operating instructions and Section 4 for AC measurements.

Maintenance

Service information for Option -09 is in Section 6; theory of operation in Section 5.

List of Replaceable Parts

List of replaceable parts for the True RMS AC PCA.

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