Grounded Thermocouple Measurements Hardware: SCXI>>Terminal Blocks>>SCXI-1303
Problem: What is a grounded thermocouple measurement? How do I use a SCXI-1102 and SCXI-1303 to measure temperature from a grounded thermocouple? Solution: Your thermocouple is grounded when it is at the same potential as the material whose temperature needs to be measured and that material is grounded. In this case the material acts as an electrical conductor to provide a path from the thermocouple to ground. The tip of the thermocouple is sometimes welded to the material because this junction provides a fast response time, but this configuration also creates an electrical connection between the thermocouple and the material. To perform a grounded thermocouple measurement with the SCXI-1102 and SCXI-1303, you need to replace the resistor network on the SCXI-1303. The resistor network that is installed in the SCXI-1303 module is a 10 Ω resistor network, but four 10 MΩ resistors are also included in the shipping kit. For instructions on how to change the resistor network, examine page 8 of the SCXI-1303 32-Channel Isothermal Terminal Block Installation Guide, which is linked below. By using the 10 MΩ resistor network, you can perform grounded thermocouple measurements. The following table, from the SCXI-1303 32-Channel Isothermal Terminal Block Installation Guide, indicates when you should use the different resistor networks: Related Links: Manual: SCXI-1303 32-Channel Isothermal Terminal Block Installation Guide Attachments:  - Selecting a Resistor Network.JPG
Report Date: 05/08/2006 Last Updated: 05/18/2007 Document ID: 3X79MM6P |
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