PT100 measurement using PXI-6229

[ShreyasP]

Dear all,

 I wish to perform temperature meaurement using 3 wire PT100. I have PXI 6229 DAQ card. I am unable to understand where should i connected the 3 wires of the PT100. I tried connecting directly to the DAQ card but i am not able to do any measurements. Upon further reading, i found I should incorporate an op amp. I have attached my circuit here. I have connected the Vout to AI3 and Ground to AI GND. I have used DAQ Assistant and tried temperature measurements. But its not working. Kindly help. 

Thanks in advance,

Shreyas

[GerdW]

Hi Shreyas,

in your drawing you're using a Pt1000…

And it seems to me you're measuring just the voltage drop over Rw1: the OpAmp inputs are connected to Rw1 and Rw2, the 1mA flows over Rw1, but Rw2 should not have any voltage drop as it's only connected to the OpAmp input…

Please check your schematics!