MAX31856

CircuitPython module for the MAX31856 Universal Thermocouple Amplifier. See examples/simpletest.py for an example of the usage.

  • Author(s): Bryan Siepert

Implementation Notes

Hardware:

Software and Dependencies:

class adafruit_max31856.MAX31856(spi, cs, thermocouple_type=3)

Driver for the MAX31856 Universal Thermocouple Amplifier

Parameters:
  • spi (SPI) – The SPI bus the MAX31856 is connected to.
  • cs (Pin) – The pin used for the CS signal.
  • thermocouple_type (ThermocoupleType) – The type of thermocouple. Default is Type K.

Quickstart: Importing and using the MAX31856

Here is an example of using the MAX31856 class. First you will need to import the libraries to use the sensor

import board
from digitalio import DigitalInOut, Direction
import adafruit_max31856

Once this is done you can define your board.SPI object and define your sensor object

spi = board.SPI()
cs = digitalio.DigitalInOut(board.D5)  # Chip select of the MAX31856 board.
sensor = adafruit_max31856.MAX31856(spi, cs)

Now you have access to the temperature attribute

temperature = sensor.temperature
fault

A dictionary with the status of each fault type where the key is the fault type and the value is a bool if the fault is currently active

Key Fault type
“cj_range” Cold junction range fault
“tc_range” Thermocouple range fault
“cj_high” Cold junction high threshold fault
“cj_low” Cold junction low threshold fault
“tc_high” Thermocouple high threshold fault
“tc_low” Thermocouple low threshold fault
“voltage” Over/under voltage fault
“open_tc” Thermocouple open circuit fault
reference_temperature

The temperature of the cold junction in degrees Celsius. (read-only)

reference_temperature_thresholds

The cold junction’s low and high temperature thresholds as a (low_temp, high_temp) tuple

temperature

The temperature of the sensor and return its value in degrees Celsius. (read-only)

temperature_thresholds

The thermocouple’s low and high temperature thresholds as a (low_temp, high_temp) tuple

class adafruit_max31856.ThermocoupleType

An enum-like class representing the different types of thermocouples that the MAX31856 can use. The values can be referenced like ThermocoupleType.K or ThermocoupleType.S Possible values are

  • ThermocoupleType.B
  • ThermocoupleType.E
  • ThermocoupleType.J
  • ThermocoupleType.K
  • ThermocoupleType.N
  • ThermocoupleType.R
  • ThermocoupleType.S
  • ThermocoupleType.T