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Thermocouple Reads a Large Negative Value When Connected to My SCXI Chassis

Hardware: SCXI>>Modules>>SCXI-1100, SCXI>>Modules>>SCXI-1102

Problem:
Why does my thermocouple measure a value on the order of -1000 degrees when hooked up through my SCXI chassis?

Solution:
When you create a Traditional NI-DAQ Virtual Channel or DAQmx Task in MAX (Measurement & Automation Explorer) for a temperature measurement, the physical channel to measure must be a channel on the SCXI module, not on the DAQ card in your computer.

In Traditional DAQ:
In the Channel Wizard, choose the SCXI module from the drop down menu when prompted "What DAQ hardware will be used?"

In DAQmx:
In the Create New Task Wizard, choose an ai (analog input) channel from the SCXI module when prompted to choose "Supported Physical Channels."

If the SCXI modules do not show up in MAX, or for help configuring the SCXI chassis, virtual channels, or DAQmx tasks, consult the SCXI Quick Start Guide (linked below).

Related Links:
Product Manuals: SCXI Quick Start Guide
Developer Zone Tutorial: Thermocouple Temperature Measurements
KnowledgeBase 2YQFCUW0: LabVIEW SCXI-1102 Thermocouple Example VI Returns Incorrect Value for Cold Junction Compensation (CJC) Temperature
KnowledgeBase 2P4HD53N: SCXI Temperature Scan VI Gives Incorrect Readings When Using the SCXI-1102 Module
KnowledgeBase 11TARTWV: Why Do I Need to Ground My Thermocouples When I Am Already Measuring Them in Differential Mode?

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Report Date: 09/23/2004
Last Updated: 08/24/2007
Document ID: 3DM9MEJZ

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