During my search for pt100 conditioning circuit. I came across the circuit.
Pls find it in the attachment.
I have build this circuit using lm358 on a general purpose board with following changes.
I have shroted the ref & vcc pin to 5v.
I am not using the MAX197 IC.
Rest of the circuit remains the same.
----------- Testing ----------
Instead of sensor I have connected 50 ohm,100 ohm,180ohm resistor (all mfrs). The output of diff amp. is 3.749v,3.74v,3.74v in the output.
1. I'm not getting good diff. in output.What is the problem ?
2. I need to measure -40 deg to 400 deg cel. Will this circuit provide me the range ?
3. What necessary changes the circuit requires ?
4. I'm using 3 wire pt100? How it should be connected in the circuit?
pls help me :(
Thanks in advance