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Allow configuration of MAX31865 resistance values #19695

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merged 1 commit into from
Oct 12, 2020
Merged

Allow configuration of MAX31865 resistance values #19695

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6 changes: 6 additions & 0 deletions Marlin/Configuration.h
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Original file line number Diff line number Diff line change
Expand Up @@ -432,6 +432,12 @@
#define DUMMY_THERMISTOR_998_VALUE 25
#define DUMMY_THERMISTOR_999_VALUE 100

// Resistor values when using a MAX31865 (sensor -5)
// Sensor value is typically 100 (PT100) or 1000 (PT1000)
// Calibration value is typically 430 ohm for AdaFruit PT100 modules and 4300 ohm for AdaFruit PT1000 modules.
//#define MAX31865_SENSOR_OHMS 100
//#define MAX31865_CALIBRATION_OHMS 430

// Use temp sensor 1 as a redundant sensor with sensor 0. If the readings
// from the two sensors differ too much the print will be aborted.
//#define TEMP_SENSOR_1_AS_REDUNDANT
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4 changes: 4 additions & 0 deletions Marlin/src/inc/SanityCheck.h
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Expand Up @@ -1845,6 +1845,10 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
#error "TEMP_SENSOR_1 is required with TEMP_SENSOR_1_AS_REDUNDANT."
#endif

#if ENABLED(MAX6675_IS_MAX31865) && (!defined(MAX31865_SENSOR_OHMS) || !defined(MAX31865_CALIBRATION_OHMS))
#error "MAX31865_SENSOR_OHMS and MAX31865_CALIBRATION_OHMS must be set in Configuration.h when using a MAX31865 temperature sensor."
#endif

/**
* Test Heater, Temp Sensor, and Extruder Pins
*/
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4 changes: 2 additions & 2 deletions Marlin/src/module/temperature.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1461,7 +1461,7 @@ void Temperature::manage_heater() {
#elif ENABLED(HEATER_0_USES_MAX6675)
return (
#if ENABLED(MAX6675_IS_MAX31865)
max31865.temperature(100, 400) // 100 ohms = PT100 resistance. 400 ohms = calibration resistor
max31865.temperature(MAX31865_SENSOR_OHMS, MAX31865_CALIBRATION_OHMS)
#else
raw * 0.25
#endif
Expand Down Expand Up @@ -2236,7 +2236,7 @@ void Temperature::disable_all_heaters() {
next_max6675_ms[hindex] = ms + MAX6675_HEAT_INTERVAL;

#if ENABLED(MAX6675_IS_MAX31865)
max6675_temp = int(max31865.temperature(100, 400)); // 100 ohms = PT100 resistance. 400 ohms = calibration resistor
max6675_temp = int(max31865.temperature(MAX31865_SENSOR_OHMS, MAX31865_CALIBRATION_OHMS));
#endif

//
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