Thermistor temperature measurement with SCXI-1102 and 1581

[bmyerspgh]

Morning Folks, how has everyone been?

So I have a new problem that I would like to request your insight on.

I am working on this project and I will be using Thermistors for my temperature measurement.  Now the RTDs I have used in the past were simple because they were linear in their functionality.  Thermistors are a different story because they use the Steinhart-Hart 3 variable equation.  Now using DAQ-Assistant, I could sample my data, get my temperature measurements, and be on my merry way.

The problem is, I need to be able to calibrate these thermisitors against NIST traceable standards on a regular basis, which means changing my A,B, and C variables if the performance of the Thermistor is outside of the specified range.

Has anyone run into this before?

Can anyone suggest a starting point on how to do this?

Are A, B, and C even changeable or are they locked in since they are "constants"?

Is there a simpler approach to take?

thank you!

[Phil_Kas]

Yes, I think that I can help. I worked with YSI thermistors a few years ago and obtained the attached spreadsheet from YSI's website. It requires that you enter three precision reference temperatures and the unit under calibration's associated resistance and the spreadsheet calculates a calibrated a, b, and c.

YSI has since been bought out by  http://www.meas-spec.com/

Good luck!