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MAX31856 breakout board with Pt100
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MAX31856 breakout board with Pt100

by AgeBee on Sun Dec 30, 2018 2:19 am

Hi,
I got the above-mentioned board and do not know which type of sensor I have to choose within method setThermocoupleType in coding found in library Adafruit MAX31856.
This is set via variable max31856_thermocoupletype_t which is an enum where all possible sensors are listed.
However, I do not know which of these are correct for a Pt100.
Thanks for your help.
Regards

AgeBee
 
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Re: MAX31856 breakout board with Pt100

by Joel_Brooks on Mon Dec 31, 2018 11:25 pm

I can't find the product that you specifically have. From what I can tell at a glance the MAX31856 is a thermocouple reader. The Pt100 is a RTD and may not work with this board. I would suggest using https://www.adafruit.com/product/270 with that board.

Joel_Brooks
 
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Re: MAX31856 breakout board with Pt100

by adafruit_support_carter on Wed Jan 02, 2019 3:01 pm

It's unfortunate that MAXIM named these two boards so similar. The one ending in 56 is for thermocouples, the one ending in 65 is for RTD's. For your PT100, you'll want this one:
https://www.adafruit.com/product/3328

NOTE - another source of confusion with the RTD breakouts is confusing the PT100 and PT1000 versions. See here:
https://learn.adafruit.com/adafruit-max ... -a-q#faq-1

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Re: MAX31856 breakout board with Pt100

by AgeBee on Fri Jan 11, 2019 4:03 pm

Thank you both.

@adafruit_support-carter: You pointed me to the RTD for the PT100.
Here https://www.adafruit.com/product/3328 I found the URL for downloading the lib (https://github.com/adafruit/Adafruit_MAX31865) which does not require setting the sensor type because it is for the PT100.

AgeBee
 
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Re: MAX31856 breakout board with Pt100

by adafruit_support_carter on Fri Jan 11, 2019 8:14 pm

There is no difference in the library. It is a hardware difference on the breakout board. And it's suuuuppper tiny - just a single resistor. That's why there are two different products. Just make sure you buy the correct breakout board for your RTD type.

Then, when you write your program, make sure you also set the correct values. See here for example:
https://github.com/adafruit/Adafruit_MA ... 65.ino#L24
Those values get used in the computing of the temperature:
https://github.com/adafruit/Adafruit_MA ... 5.cpp#L116

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Re: MAX31856 breakout board with Pt100

by AgeBee on Sat Jan 12, 2019 3:56 am

Thanks a bunch adafruit_support-carter. Your remarks were really of great help for me. I appreciate that greatly.

AgeBee
 
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Please be positive and constructive with your questions and comments.