scxi-1102 thermistor measurement

[bmyerspgh]

I am currently setting up a long term temperature measurement project, and I have a question regarding the accuracy of the SCXI-1102 when used with a 10,000 ohm J type thermistor. 

I am supplying a constant current of 100uA from my SCXI-1581 and reading the voltage across the thermistor on the SCXI-1102, so that is pretty straight forward.

Where I am running into questions is, the 1102 can be set for either a +/- 100mV input, or a +/- 10V input.  The range that I plan to be working in, based on the characteristic curve of the thermistor is 30 to 40C, or voltages of 0.8057 to 0.5326 V.  This is important because I am currently operating under a calibration specification of +/-1.0 C.

So, my questions are:

Is the SCXI-1102 sensitive enough to accurately measure this range of voltages?

Is the SCXI-1581 consistent enough to "significantly" affect my measurements?

thank you

[ManLongAtNI]

Hello bmyerspgh,

The defined voltages in the above post suggest you would be measuring in the +/- 10V range. In which case, (worst case scenario-after calibration) you would have an offset error of 600uV, 0.04% of the reading gain error, and 50uV system noise. As for the 1581, you have +/- 0.05% accuracy.

Keep in mind this does not include the accuracy of you DAQ device.

For more information on the above specifications, please reference the SCXI-1102 User Manual and SCXI-1581 User Manual