Agilent Technologies 34970A - User Manual

Agilent 34970A
Data Acquisition/Switch Unit
Product Overview
Agilent performance
at a fraction of the cost
of other standalone
data acquisition systems

Summary

Product Overview

Price and Performance Advantages

Key Features and Benefits

Summarizes instrument's measurement accuracy, flexibility, modularity, user-friendliness, and included software.

More Power and Flexibility

Versatility for Data Acquisition Applications

Data Logger and Switch System Roles

Highlights its use as a low-cost data logger and a high-quality signal routing solution.

Easy Data Logging with Software

BenchLink Data Logger II Software

Focuses on the software for data gathering and analysis.

Input Signal Capabilities and Features

Versatile Alarms and Scanning

Details per-channel alarm limits and the simplified automatic scanning process.

Input Monitoring and Memory

Covers real-time input monitoring and nonvolatile data storage with timestamps.

Automated Test System Capabilities

Powerful Measurement Performance

Details the internal DMM capabilities and accuracy.

Flexible Functionality

Discusses configurable channels and built-in signal conditioning for various measurements.

Software Drivers for System Integration

Low-Cost Switching Solutions

Module Functionality and Design

Covers module design for broad switching needs, density, and connections.

Easy Scanning Control

Explains scan control methods.

Customizing with Plug-in Modules

Module Design Advantages

Covers higher throughput, density, and convenient connections in module design.

Agilent Quality and Reliability

Relay Maintenance System

Explains the proprietary relay maintenance system.

Spec Interpretation Guide

Accuracy Specifications Overview

Measurement and Operating Characteristics

Measurement Characteristics

Details measurement methods and parameters.

Operating Characteristics

Lists system speeds and interface performance.

System Specifications

Scanning Inputs and Alarms

Covers scanning inputs, alarms, and system features.

System Features and General Specs

Details features, power, environment, and safety.

Software and Interface Support

Discusses BenchLink software, requirements, and interface drivers.

Modules Specifications Overview

Multiplexer Selection Guide

34901 A General-Purpose Multiplexer

Description of the 34901A module.

Rack Mounting and Dimensions

Ordering Information and Support

Mainframe and Module Options

Lists mainframe and module part numbers for ordering the system.

Accessories and Related Literature

Lists available accessories, related literature, and datasheets for the product.

Agilent Support Services

Covers Agilent's test and measurement support, services, and online assistance.

Overview

1. Function Description
2. Usage Features
3. Maintenance Features

The Agilent 34970A is a versatile Data Acquisition/Switch Unit designed to offer powerful measurement performance, flexibility, and ease of use for a wide range of applications, from data logging to automated test and switching systems. It aims to provide Agilent-level performance at a fraction of the cost of other standalone data acquisition systems.

Function Description

At its core, the 34970A integrates a high-performance 6½-digit (22-bit) internal Digital Multimeter (DMM) within a compact 3-slot cardcage. This DMM is capable of directly measuring 11 different functions without the need for expensive external signal conditioning. These functions include temperature (with thermocouples, RTDs, and thermistors), AC/DC volts, 2- and 4-wire resistance, frequency, period, and AC/DC current. The internal DMM is optically isolated and shielded from the 34970A's earth-referenced circuitry and computer interface, providing up to 300 V of input isolation, which is crucial for reducing ground loop and common mode voltage errors in long wiring runs or with floating measurement sources.

The modular design of the 34970A allows users to customize the unit with up to three plug-in modules from a selection of eight different switch and control modules. These modules include low-frequency and RF multiplexers, matrix switches, general-purpose switches, and a multifunction module that offers digital input/output, analog output, and totalizer capabilities. This modularity enables the 34970A to be configured for specific needs and expanded as applications grow.

The unit can function as:

• A Data Logger: When configured with a 20-channel relay multiplexer, it becomes a powerful, low-cost data logger for characterization applications. It features 6½-digit resolution, 0.004% basic 1-year DCV accuracy, and 50,000-reading nonvolatile memory with timestamps.
• A Data Acquisition Front-End: For automated test systems, the 34970A provides excellent measurement performance, accuracy, resolution, and speed. It offers scan rates of up to 250 channels/second.
• A Switch System: The mainframe can be ordered without the internal DMM for a lower-cost, high-quality signal routing solution, ideal for connecting test signals to and from a Device Under Test (DUT) and other instruments like external DMMs, scopes, counters, and power supplies. The DMM can be retrofitted later if needed.

Usage Features

The 34970A is designed for ease of use, featuring an intuitive front panel with task-oriented, self-guiding menus. Key usage features include:

• Per-Channel Configurability: Each measurement channel can be independently configured for different measurement functions, scaling factors (Mx+B), and alarm limits, even on adjacent channels. This eliminates the need for expensive external signal conditioning.
• Built-in Signal Conditioning: The architecture minimizes external wiring, reduces hidden costs by avoiding extra cables and breakout boxes, simplifies configuration, and improves reliability. Measurement accuracies are specified to include all system-related errors.
• Versatile Alarms: Alarms can be set on a per-channel basis with high and low limits. The 34970A compares readings to these limits and flags out-of-range measurements. Four TTL alarm outputs can be assigned to any input channel to trigger external alarms or control systems without a PC.
• Scanning Capabilities: The 34970A automatically builds a scan list of all configured inputs in ascending order. Scans can be paced by an internal timer, manual front-panel button press, software commands, or external TTL trigger pulses.
• Monitor Display Mode: A special display mode allows continuous monitoring of a selected input channel, updating the display with new readings even during a scan. This is useful for keeping an eye on critical inputs or troubleshooting.
• Nonvolatile Memory: All readings are automatically time-stamped and stored in a nonvolatile 50,000-reading memory, which can hold over a week's worth of data (for 20 channels scanned every five minutes). This memory retains data even after power is removed, allowing for remote data collection and later upload to a PC. It also stores the system configuration, enabling the 34970A to resume scanning after a power loss.
• Free Software: Agilent BenchLink Data Logger II software is included with every standard 34970A. This software provides a familiar Microsoft Windows® interface for test configuration, real-time data display, and analysis, saving users time and effort in writing or configuring software. Drivers are also available for Agilent VEE and National Instruments LabVIEW.
• Convenient Connections: On-module screw-terminal connectors make wiring easy, with built-in strain-relief cable routing and cable tie points to keep wiring secure. An internal analog bus routes signals from low-frequency multiplexers directly to the internal DMM, eliminating external connections.
• Built-in Interfaces: The 34970A comes standard with GPIB and RS-232 interfaces for easy integration into test systems.

Maintenance Features

The 34970A incorporates features designed to enhance reliability and simplify maintenance:

• Rugged Design: Engineers designed reliability into the 34970A with a rugged enclosure, state-of-the-art surface mount construction, reduced parts counts, and rigorous testing.
• Relay Maintenance System: The unit uses a proprietary relay maintenance system to predict relay end-of-life and prevent costly downtime. It automatically counts every individual switch closure and stores this data in nonvolatile memory on each module. Users can query the total number of cycles on any individual channel to schedule maintenance proactively and avoid erratic failures.
• Power Fail Recovery: The system can automatically resume scanning after a power failure.
• Battery-Backed Real-Time Clock: A real-time clock paces scans and timestamps readings, ensuring accurate data logging even during extended operations.

Agilent Technologies 34970A Specifications