Customizable redundant temperature sensor assignment

Marlin/Configuration.h

@@ -472,6 +472,7 @@
 #define TEMP_SENSOR_PROBE 0
 #define TEMP_SENSOR_CHAMBER 0
 #define TEMP_SENSOR_COOLER 0
+#define TEMP_SENSOR_REDUNDANT 0
 
 // Dummy thermistor constant temperature readings, for use with 998 and 999
 #define DUMMY_THERMISTOR_998_VALUE  25
@@ -483,11 +484,6 @@
 //#define MAX31865_SENSOR_OHMS_1      100
 //#define MAX31865_CALIBRATION_OHMS_1 430
 
-// 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
-#define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10
-
 #define TEMP_RESIDENCY_TIME         10  // (seconds) Time to wait for hotend to "settle" in M109
 #define TEMP_WINDOW                  1  // (°C) Temperature proximity for the "temperature reached" timer
 #define TEMP_HYSTERESIS              3  // (°C) Temperature proximity considered "close enough" to the target
@@ -500,6 +496,28 @@
 #define TEMP_CHAMBER_WINDOW          1  // (°C) Temperature proximity for the "temperature reached" timer
 #define TEMP_CHAMBER_HYSTERESIS      3  // (°C) Temperature proximity considered "close enough" to the target
 
+/**
+ * Redundant Temperature Sensor (TEMP_SENSOR_REDUNDANT)
+ *
+ * Use a temp sensor as a redundant sensor for another reading. Select an unused temperature sensor, and another
+ * sensor you'd like it to be redundant for. If the two thermistors differ by TEMP_SENSOR_REDUNDANT_MAX_DIFF (°C),
+ * the print will be aborted. Whichever sensor is selected will have its normal functions disabled; i.e. selecting
+ * the Bed sensor (-1) will disable bed heating/monitoring.
+ *
+ * Use the following to select temp sensors:
+ *    -5 : Cooler
+ *    -4 : Probe
+ *    -3 : not used
+ *    -2 : Chamber
+ *    -1 : Bed
+ *   0-7 : E0 through E7
+ */
+#if TEMP_SENSOR_REDUNDANT
+  #define TEMP_SENSOR_REDUNDANT_SOURCE     1  // The sensor that will provide the redundant reading.
+  #define TEMP_SENSOR_REDUNDANT_TARGET     0  // The sensor that we are providing a redundant reading for.
+  #define TEMP_SENSOR_REDUNDANT_MAX_DIFF  10  // (°C) Temperature difference that will trigger a print abort.
+#endif
+
 // Below this temperature the heater will be switched off
 // because it probably indicates a broken thermistor wire.
 #define HEATER_0_MINTEMP   5

Marlin/Configuration_adv.h

@@ -125,6 +125,12 @@
   #define PROBE_BETA                   3950    // Beta value
 #endif
 
+#if TEMP_SENSOR_REDUNDANT == 1000
+  #define REDUNDANT_PULLUP_RESISTOR_OHMS   4700    // Pullup resistor
+  #define REDUNDANT_RESISTANCE_25C_OHMS    100000  // Resistance at 25C
+  #define REDUNDANT_BETA                   3950    // Beta value
+#endif
+
 //
 // Hephestos 2 24V heated bed upgrade kit.
 // https://store.bq.com/en/heated-bed-kit-hephestos2

Marlin/src/HAL/LPC1768/tft/xpt2046.h

@@ -54,7 +54,7 @@ enum XPTCoordinate : uint8_t {
   XPT2046_Z2 = 0x40 | XPT2046_CONTROL | XPT2046_DFR_MODE,
 };
 
-#if !defined(XPT2046_Z1_THRESHOLD)
+#ifndef XPT2046_Z1_THRESHOLD
   #define XPT2046_Z1_THRESHOLD 10
 #endif
 

Marlin/src/HAL/STM32/tft/xpt2046.h

@@ -56,7 +56,7 @@ enum XPTCoordinate : uint8_t {
   XPT2046_Z2 = 0x40 | XPT2046_CONTROL | XPT2046_DFR_MODE,
 };
 
-#if !defined(XPT2046_Z1_THRESHOLD)
+#ifndef XPT2046_Z1_THRESHOLD
   #define XPT2046_Z1_THRESHOLD 10
 #endif
 

Marlin/src/HAL/STM32F1/tft/xpt2046.h

@@ -54,7 +54,7 @@ enum XPTCoordinate : uint8_t {
   XPT2046_Z2 = 0x40 | XPT2046_CONTROL | XPT2046_DFR_MODE,
 };
 
-#if !defined(XPT2046_Z1_THRESHOLD)
+#ifndef XPT2046_Z1_THRESHOLD
   #define XPT2046_Z1_THRESHOLD 10
 #endif
 

Marlin/src/MarlinCore.cpp

@@ -1150,10 +1150,10 @@ void setup() {
   SETUP_RUN(HAL_init());
 
   // Init and disable SPI thermocouples; this is still needed
-  #if TEMP_SENSOR_0_IS_MAX_TC
+  #if TEMP_SENSOR_0_IS_MAX_TC || (TEMP_SENSOR_REDUNDANT_IS_MAX_TC && TEMP_SENSOR_REDUNDANT_SOURCE == 0)
     OUT_WRITE(MAX6675_SS_PIN, HIGH);  // Disable
   #endif
-  #if TEMP_SENSOR_1_IS_MAX_TC
+  #if TEMP_SENSOR_1_IS_MAX_TC || (TEMP_SENSOR_REDUNDANT_IS_MAX_TC && TEMP_SENSOR_REDUNDANT_SOURCE == 1)
     OUT_WRITE(MAX6675_SS2_PIN, HIGH); // Disable
   #endif
 

Marlin/src/gcode/temp/M105.cpp

@@ -35,11 +35,7 @@ void GcodeSuite::M105() {
 
   #if HAS_TEMP_SENSOR
 
-    thermalManager.print_heater_states(target_extruder
-      #if ENABLED(TEMP_SENSOR_1_AS_REDUNDANT)
-        , parser.boolval('R')
-      #endif
-    );
+    thermalManager.print_heater_states(target_extruder OPTARG(HAS_TEMP_REDUNDANT, parser.boolval('R')));
 
     SERIAL_EOL();