Pico Technical Support and Discussion Forum

tretlo · Newbie Joined: 19 Jan 2007 Posts: 1

Hello and thanks for this great forum.

I am interested in using the pt100 to measure temperature in a custom circuit with a PIC microcontroller. In this case, my PIC software would have to convert the probe resistance, via an ADC, to temperature. I would therefore presumably have no need for the pt104, correct?

My question has two parts.

1) Is a schematic or other documentation available for a recommended input circuit for the pt100? In other words, how do you suggest I convert the probe resistance to a voltage that can be fed to an ADC? Any information regarding suggested analog design would be helpful.

2) Do you have any suggestions for the routine to convert the digitized resistance measurement to temperature? I did notice the linearization equation on your website, but I was wondering if further implementation recommendations are available.

I am basically hoping to emulate parts of the pt104 functionality in my own design so I can easily integrate the measurements into a larger control system. If it goes well, we may be purchasing many probes.

Thanks in advance for your help,
Ryan

davidj · Posted: Tue Jan 23, 2007 4:01 pm Post subject:

Hello Ryan

Thanks for the good comments.

We suggest you take a look an an ADC aimed at PT100 / RTD measurements such as this one:

http://tinyurl.com/2jcpqs

see P39. Also a few pages up from this there is some C code which may be of interest.

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Pico Technical Support and Discussion Forum