SCXI-1328 temperature measurement accuracy

[efour]

The catalog says temperature accuracy of SCXI-1328 is 0.5C. If I use three thermocouple, does 0.5C uncertainty exist for all results from each thermocouple? Or, only cold junction has 0.5C uncertainty so that all results have the same offset from real value. In latter case, what is the accuracy of temperature measurement?

[Scott_R]

Hello efour,

0.5 ºC is the accuracy for the Cold Junction Compensation (CJC) for the SCXI 1328 terminal block for temperatures ranging from 15-35 ºC. Each thermocouple measurement would be subject to this factor. That is the only factor from the 1328 that will affect your temperature measurements.

The overall measurement accuracy of your system would be dependent upon what module you have the 1328 block attached to and what data acquisition (DAQ) card you are using. There is an accuracy calculator available on our website. You can reach it at

Accuracy Calculator
http://www.ni.com/advisor/accuracy/

With this tool, you can enter in your DAQ and SCXI card information. It will return the accuracy of each and then the overall system accuracy. It do
esn�t include the terminal block, though.

General information about taking thermocouple measurements can be found at:

Thermocouple Temperature Measurements
http://zone.ni.com/devzone/conceptd.nsf/webmain/4C54819521D3503786256D73006E8BE9?opendocument

Let me know if you have any further questions on this issue.

Scott Romine,
National Instruments