Datasheet

notes/AN709_0.pdf (https://adafru.it/swC)

It's fast and seems to work very well! We have a one-stop function that does everything for you, just call:

Where the first argument is the resistance of the RTD at 0°C (for PT100 that's 100) and the second argument is the

value of the reference resistor. This function returns the tempreature in °C

Faults

The MAX31865 has a wide-ranging fault mechanism that can alert you via pin or function when something is amiss.

Don't forget to test this functionality before relying on it!

You can read faults with

Which will return a uint8_t type with bits set for each of 6 different fault types. You can test for each one with this set of

code:

In particular, the last four are ones that indicate a hardware failure. The first two are threshold faults, we don't have

code for setting those thresholds at this time.

max.temperature(100, RREF)

max.readFault()

// Check and print any faults

uint8_t fault = max.readFault();

if (fault) {

Serial.print("Fault 0x"); Serial.println(fault, HEX);

if (fault & MAX31865_FAULT_HIGHTHRESH) {

Serial.println("RTD High Threshold");

}

if (fault & MAX31865_FAULT_LOWTHRESH) {

Serial.println("RTD Low Threshold");

}

if (fault & MAX31865_FAULT_REFINLOW) {

Serial.println("REFIN- > 0.85 x Bias");

}

if (fault & MAX31865_FAULT_REFINHIGH) {

Serial.println("REFIN- < 0.85 x Bias - FORCE- open");

}

if (fault & MAX31865_FAULT_RTDINLOW) {

Serial.println("RTDIN- < 0.85 x Bias - FORCE- open");

}

if (fault & MAX31865_FAULT_OVUV) {

Serial.println("Under/Over voltage");

}

max.clearFault();

}