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Topic: MAX31865 problem (Read 109 times) previous topic - next topic

pepe12311

Hello everyone and sorry for my English
I am testing the max31865 with PT100, I have installed three, with adafruit's test program with an Arduino uno on a breadboard
The problem I have is that when I start or reset the board, "all" the temperatures all the time are wrong, but it doesn't give an error.
Examples:
RTD value: 26898, Temperature = 733.09. If I heat them, the temperatures vary.
But if I disconnect and reconnect the power, only from the Max31865 boards, instantly the temperatures are correct.
Example: RTD value: 8224, Temperature = 20.36
If I disconnect and reconnect from the whole set, they go bad again.
I have tried delays, etc. without results.
Any ideas?
It seems like I have to power the arduino first and then the boards, but this is not practical, in the final assembly.

Koepel

Which MAX31865 modules do you have ? Can you give a link to where you bought them ?
The Arduino Uno is a 5V board and the MAX31865 is a 3.3V sensor. The Adafruit module is made compatible for 5V Arduino boards.

michalpuk

Maybe MAX module boots faster than Arduino and doesn't detects it properlly. What kind of delay did you did for MAX?

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