You will want to use the best measurement system to take your thermocouple measurements. The following Knowledge Base article covers our recommended hardware to perform thermocouple measurements.
What is the Recommended NI Hardware for Thermocouple Measurements?
http://digital.ni.com/public.nsf/websearch/F0196F5B6CD8F60286256D4B00728B78?OpenDocument
While the SCXI-1122 is not mentioned in this article, you may still use it to perform thermocouple measurements. You may want to consider using the differential input mode instead of RSE. Differential mode is the best method when acquiring from a floating signal source such as a thermocouple. DIFF mode does the best job of reducing noise and rejecting unwanted common-mode voltage.
Additionally, there is a
n excellent Application Note available on our website which covers approaches to noise reduction and elimination.
Field Wiring and Noise Considerations for Analog Signals
http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/01f147e156a1be15862568650057df15?OpenDocument
Regards,
Justin Britten
Applications Engineer
National Instruments
