AnsweredAssumed Answered

AD595CDZ accuracy and precision tuning

Question asked by jennyb on Aug 11, 2016
Latest reply on Aug 15, 2016 by iamPhil

Hi. I'm playing with the thermocouple IC AD595CDZ and am planning on making a PCB shield for my Arduino Mega2560. I'm using a 1000 ohm platinum RTD.

 

However, I have it plugged up on a breadboard to test it, (hooked up just like Figure 1 on pg 3 of the datasheet, with 12VDC input power), and I'm getting readings at my Arduino, and they are changing with temperature increase/decrease, but they are drastically off, from the table provided in the data sheet. When i look for the reading to equal my ambient temperature (around 77 degrees) the readings associated with that are around 120F.

 

I thought that adding a 1M resistor to ground from the thermocouple could change the readings but that did nothing,...matter fact it stopped reading/changing with temperature.

 

Am I doing something wrong from a hardware perspective? Or should I be modifying software equations to compensate for difference? This is the only solution i can think of, but not sure if that's appropriate approach.

 

thank you for your time.

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