dusttyler13
Posts: 6
Joined: Fri May 31, 2013 11:31 am

Pt100 Temperature Sensor RTD-to-Digital Converter (MAX31865)

Fri May 31, 2013 12:00 pm

Hi,
I am attempting to use a four-wire Pt100 Temperature Sensor to read temperatures between 0 and 200 C. I would like to use a RTD-to-Digital Converter (MAX31865), as opposed to building my own circuit. I am just a little confused on how to use the converter. There is a Serial Output pin on the MAX31865, which is where I assume I will be hooking up the Pi. I'm really quite new at this, so I apologize if this is a dumb question. Any help would be greatly appreciated,

Thanks

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joan
Posts: 12738
Joined: Thu Jul 05, 2012 5:09 pm
Location: UK

Re: Pt100 Temperature Sensor RTD-to-Digital Converter (MAX31

Fri May 31, 2013 1:51 pm

It uses the SPI interface (the Pi does have a SPI interface).

Is the 4-wire Pt100 especially accurate? The DS18B20 temperature sensor seems to be a more popular choice.

Edited to add: the 0-200 centigrade range seems to be the advantage of the Pt100.

Maxion
Posts: 138
Joined: Mon Dec 03, 2012 2:22 pm

Re: Pt100 Temperature Sensor RTD-to-Digital Converter (MAX31

Fri May 31, 2013 2:23 pm

The 31855 is similar to the 31865 but it is for thermocouples. There are quite a few tutorials and example scripts available for it for the Pi. IT also uses the SPI interface.

https://github.com/Tuckie/max31855/blob ... ax31855.py

dusttyler13
Posts: 6
Joined: Fri May 31, 2013 11:31 am

Re: Pt100 Temperature Sensor RTD-to-Digital Converter (MAX31

Sun Jun 02, 2013 4:54 pm

Hmmm yeah the 31855 certainly does seem to have more resources for the Pi. May end up needing to change gears and switch to thermocouples. Thanks for the replies! Very helpful

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