Arduino library for 14-bit MAX31855 K-thermocouple to digital converter

Other Hardware Sensors
1

Hi,

The best Arduino library for MAX31855 sensor. Works with hardware SPI or emulates bit-bang SPI.

It has improved diagnostic functions and reports:

  • shorting the thermocouple to ground
  • shorting to power
  • breaking the thermocouple
  • thermocouple temperature*
  • cold junction temperature*

*Library returns 2000, if thermocouple open/shorted or a communication error has occurred.

Warning - MAX31855 max. power supply voltage is 3.6v

It is STRONGLY recommended to add a 10nF/0.01mF capacitor, placed across the T+ and T- pins, to filter noise/false readings on the thermocouple lines.

There are two PCB version on ebay. First has config pads on the back to work with MAX31855 or MAX6675.

The second board must be modified before use with the MAX31855, see pic

789×585 64.1 KB

Download link - GitHub - enjoyneering/MAX31855: Arduino library for 14-bit MAX31855 K-thermocouple to digital converter

2

Just found I had a board with a similar problem, the thermocouple was grounding, it has the number 54 marked on one corner of the board. Im going to try and cut the tracks and see if that works tomorrow. Ill post if that sorts the problem on the board I have. Hopefully this thread has saved me a lot of time trying to get it working.
Thanks for posting.

3

BinaryA:
Just found I had a board with a similar problem, the thermocouple was grounding, it has the number 54 marked on one corner of the board. Im going to try and cut the tracks and see if that works tomorrow. Ill post if that sorts the problem on the board I have. Hopefully this thread has saved me a lot of time trying to get it working.
Thanks for posting.

any success? what lib did you use?

4

Thanks for these postings!

I've just been trying to get a Max13855 board ( with "54" in the corner) working for a couple of hours -it too had a gnd short on the thermocouple , as shown above.

Removed this and got it working fine .

Just a reminder -use a level shifter on the connections and 3.3v power supply. Showed some very high internal temperatures (100+C), and occasional errors, when I forgot this for the signal connections !!

using the " Adafruit_MAX31855 " library.

5

Showed some very high internal temperatures (100+C), and occasional errors, when I forgot this for the signal connections !!

The capacitor in parallel "-T" and "+ T" at 10nF/0.01mF is OBLIGATORY!!! MAX31855 shows inadequate values without it, from time to time.

6

enjoyneering:
Download link - GitHub - enjoyneering/MAX31855: Arduino library for 14-bit MAX31855 K-thermocouple to digital converter

Starred and watched on GitHub. Tanks for sharing!

7

Hola que tal amigos, estoy probando usar el MAX31588 con su librería correspondiente conectado a una termocupla tipo T los valores que me arroja por el puerto serial son inadecuados que me recomiendan hacer?

Es necesario poner el condensador de 0.01 uf ?

nota: Es la primera que uso este modulo leei las especificaciones antes de comprarlo y es apto para la termocupla que estoy usando en este caso.

Saludos!!

8

enjoyneering:
The capacitor in parallel "-T" and "+ T" at 10nF/0.01mF is OBLIGATORY!!! MAX31855 shows inadequate values without it, from time to time.