Multiple RTD measurement

[MGarman]

We are looking for a solution to measure multiple (at least 😎 RTDs in Liquid Nitrogen and record then convert their resistances to a live feed of temperature to ensure that the temperature in different areas of a cryostat is uniform/ changing at the same rate. I know labView could be used for the conversion but any information on DAQ systems would be a great help. 

The RTDs are LakeShore PT-102-AL-2S series.

Kind regards,

Matt

[Henrik_Volkers]

At a first glance I would say two 9217 modules would do the job.

However they are specified down to -200°C ....   but should measure even lower temperatures/resistors  

BUT:  a quick look at the provided RTD conversion vi show that you migth need to program your own back conversion since it only covers R_0, A and B  and as far as I remember you would need also parameter C in the lower range... 

Depending on the needed accuracy needed, I would propose a individual calibration including the DAQs.  Just put all sensors close together and take one or more runs over your temperature range of interest.  Record the differences and use them to correct the individual sensors.... 

[MGarman]

Hi Henrik,

Thanks for the information, the RTDs have already been calibrated by LakeShore using two point calibration. Do you have a link to the RTD conversion calculation as I had assumed it was fairly easy to do in LabView?

Kind regards,

Matt