NI 9219 to measure temperature using thermistor in 4-wire mode

[arihant]

I am measuring temperature with thermistor sensor using NI 9219 AI module on a cDAQ 9178 chassis. There is no issue when measurement is done using 2-wire mode and displayed result is in complete agreement with calibration report provided by Thermistor manufacturer. However we want to take measurement over a long distance. To get accurate result, we used 4-wire resistance measurement scheme. But the displayed result shows Zero resitance (short). The connections are proper and checked multiple times. I am not able to figure out the error. Whether NI 9219 cannot measure Thermistor resistance in 4-wire mode.

At 25 deg C, Rthermistor = 10k.

Need help.

[stockson · Accepted solution]

Hi, what do you mean by "long distance"? What type of wires do you use?

Does the connection look like this?

Also - the program you sent is configured to use 2-wire, not 4-wire method.

[arihant]

My bad.

I switched the Pin 4 connection with Pin 6. I will try after rectifying it.

Thanks for your nice connection visual.

[BhavinSyd]

@arihant 

were you able to get this working? What is the accuracy you are getting?

Thanks

Bhavin

[arihant]

Sorry as I could not reply.

Yes, I was able yo do it. 

[santo_13]

Please mark the appropriate reply as Solution if already solved.