National Instruments SCXI-1503 Front Connector

Chapter 2 Connecting Signals

In this configuration, the lead-resistance voltage drop across RL3 is

converted into a common-mode voltage that is rejected by the differential

amplifier. Also, the polarity of the lead-resistance voltage drops across RL1

and RL2 are series opposing, relative to the inputs of the differential

amplifier, eliminating their effect on the voltage measured across RT.

Note RL1 and RL2 are assumed to be equal.

The effectiveness of this method depends on the matching of the current

sources. Each current source on the SCXI-1503 has an accuracy of ±0.05%.

This accuracy results in a worst-case matching of ±0.1%. Refer to the

Chapter4, Theory of Operation, for accuracy considerations of RTDs and

thermistors.

Front Connector

The pin assignments for the SCXI-1503 front signal connector are shown

in Table 2-1.

Note Do not make any connections to RSVD pins.

Contents

Main Page Important Information Warranty Copyright Trademarks Patents Conventions Contents Chapter 1 About the SCXI-1503 Chapter 2 Connecting Signals Chapter 3 Configuring and Testing Chapter 4 Theory of Operation Chapter 5 Using the SCXI-1503 Page Tables About the SCXI-1503 What You Need to Get Started National Instruments Documentation Page Installing Application Software, NI-DAQ, and the E/M Series DAQ Device Installing the SCXI-1503 Module into the SCXI Chassis Installing the Terminal Block Configuring the SCXI System Software Page Connecting Signals Analog Input Signal Connections Ground-Referencing the Signals Connecting Resistive Devices to the SCXI-1503 4-Wire Configuration 2-Wire Configuration 3-Wire Resistive Sensor Configuration Lead-Resistance Compensation Using a 3-Wire Resistive Sensor and Two Matched Current Sources Figure 2-4. 3-Wire Configuration Using Matched Current Sources Front Connector Table 2-1. Front Signal Pin Assignments Page Rear Signal Connector Table 2-3 shows the SCXI-1503 module rear signal connector pin assignments. Table 2-3. Rear Signal Pin Assignments Rear Signal Connector Descriptions Page Configuring and Testing SCXI-1503 Software-Configurable Settings Common Software-Configurable Settings Gain/Input Range Input Coupling Configurable Settings in MAX NI-DAQmx Creating a Global Channel or Task Verifying the Signal Verifying the Signal in NI-DAQmx Using a Task or Global Channel Page Page Chapter 4 Theory of Operation Figure 4-1. Block Diagram of SCXI-1503 SCXI-1503 User Manual 4-2 ni.com Front Signal Connector Rear Signal Connector + Rear Signal Connector, SCXIbus Connector, and SCXIbus Interface Digital Control Circuitry Analog Circuitry Analog Input Channels Operation of the Current Sources Theory of Multiplexed Operation Measuring Temperature with Resistive Transducers RTDs RTD Measurement Errors The Relationship Between Resistance and Temperature in RTDs Page Page Page Thermistors Thermistor Measurement Circuits Resistance/Temperature Characteristic of Thermistors Page Using the SCXI-1503 Developing Your Application in NI-DAQmx Typical Program Flowchart Figure 5-1. Typical Program Flowchart for Voltage Measurement Channels General Discussion of Typical Flowchart Creating a Task Using DAQ Assistant or Programmatically Adjusting Timing and Triggering Configuring Channel Properties Page Page Acquiring, Analyzing, and Presenting Completing the Application Developing an Application Using LabVIEW Page Using a NI-DAQmx Channel Property Node in LabVIEW Specifying Channel Strings in NI-DAQmx Text Based ADEs LabWindows/CVI Measurement Studio (Visual Basic 6, .NET, and C#) Programmable NI-DAQmx Properties Calibration Internal/Self-Calibration External Calibration Page A Specifications Analog Input Input Characteristics Transfer Characteristics RTD Measurement Accuracy Amplifier Characteristics Dynamic Characteristics Filter Stability Excitation Power Requirements From SCXI Backplane Environmental Physical Maximum Working Voltage Safety Electromagnetic Compatibility CE Compliance Waste Electrical and Electronic Equipment (WEEE) B Removing the SCXI-1503 Removing the SCXI-1503 from MAX Removing the SCXI-1503 from a Chassis Figure B-1. Removing the SCXI-1503 C Common Questions Page Page Glossary Numbers/Symbols A B C D E G I J L M N O P R S T U V W Index Numerics A C D E F G I O P Q R S T V