🐛 Fix Bed/Chamber PID Autotune with MPCTEMP (#23983)

Marlin/src/MarlinCore.cpp

@@ -417,7 +417,9 @@ inline void manage_inactivity(const bool no_stepper_sleep=false) {
   if (do_reset_timeout) gcode.reset_stepper_timeout(ms);
 
   if (gcode.stepper_max_timed_out(ms)) {
-    SERIAL_ERROR_MSG(STR_KILL_INACTIVE_TIME, parser.command_ptr);
+    SERIAL_ERROR_START();
+    SERIAL_ECHOPGM(STR_KILL_PRE);
+    SERIAL_ECHOLNPGM(STR_KILL_INACTIVE_TIME, parser.command_ptr);
     kill();
   }
 
@@ -475,7 +477,9 @@ inline void manage_inactivity(const bool no_stepper_sleep=false) {
     // KILL the machine
     // ----------------------------------------------------------------
     if (killCount >= KILL_DELAY) {
-      SERIAL_ERROR_MSG(STR_KILL_BUTTON);
+      SERIAL_ERROR_START();
+      SERIAL_ECHOPGM(STR_KILL_PRE);
+      SERIAL_ECHOLNPGM(STR_KILL_BUTTON);
       kill();
     }
   #endif

Marlin/src/core/language.h

@@ -199,16 +199,20 @@
 #define STR_FILAMENT_CHANGE_INSERT_M108     "Insert filament and send M108"
 #define STR_FILAMENT_CHANGE_WAIT_M108       "Send M108 to resume"
 
-#define STR_STOP_BLTOUCH                    "!! STOP called because of BLTouch error - restart with M999"
-#define STR_STOP_UNHOMED                    "!! STOP called because of unhomed error - restart with M999"
-#define STR_KILL_INACTIVE_TIME              "!! KILL caused by too much inactive time - current command: "
-#define STR_KILL_BUTTON                     "!! KILL caused by KILL button/pin"
+#define STR_STOP_PRE                        "!! STOP called because of "
+#define STR_STOP_POST                       " error - restart with M999"
+#define STR_STOP_BLTOUCH                    "BLTouch"
+#define STR_STOP_UNHOMED                    "unhomed"
+#define STR_KILL_PRE                        "!! KILL caused by "
+#define STR_KILL_INACTIVE_TIME              "too much inactive time - current command: "
+#define STR_KILL_BUTTON                     "KILL button/pin"
 
 // temperature.cpp strings
-#define STR_PID_AUTOTUNE_START              "PID Autotune start"
-#define STR_PID_BAD_HEATER_ID               "PID Autotune failed! Bad heater id"
-#define STR_PID_TEMP_TOO_HIGH               "PID Autotune failed! Temperature too high"
-#define STR_PID_TIMEOUT                     "PID Autotune failed! timeout"
+#define STR_PID_AUTOTUNE                    "PID Autotune"
+#define STR_PID_AUTOTUNE_START              " start"
+#define STR_PID_BAD_HEATER_ID               " failed! Bad heater id"
+#define STR_PID_TEMP_TOO_HIGH               " failed! Temperature too high"
+#define STR_PID_TIMEOUT                     " failed! timeout"
 #define STR_BIAS                            " bias: "
 #define STR_D_COLON                         " d: "
 #define STR_T_MIN                           " min: "
@@ -219,7 +223,7 @@
 #define STR_KP                              " Kp: "
 #define STR_KI                              " Ki: "
 #define STR_KD                              " Kd: "
-#define STR_PID_AUTOTUNE_FINISHED           "PID Autotune finished! Put the last Kp, Ki and Kd constants from below into Configuration.h"
+#define STR_PID_AUTOTUNE_FINISHED           " finished! Put the last Kp, Ki and Kd constants from below into Configuration.h"
 #define STR_PID_DEBUG                       " PID_DEBUG "
 #define STR_PID_DEBUG_INPUT                 ": Input "
 #define STR_PID_DEBUG_OUTPUT                " Output "

Marlin/src/feature/bltouch.cpp

@@ -111,11 +111,8 @@ bool BLTouch::deploy_proc() {
     // Last attempt to DEPLOY
     if (_deploy_query_alarm()) {
       // The deploy might have failed or the probe is actually triggered (nozzle too low?) again
-      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("BLTouch Recovery Failed");
-
-      SERIAL_ERROR_MSG(STR_STOP_BLTOUCH);  // Tell the user something is wrong, needs action
-      stop();                              // but it's not too bad, no need to kill, allow restart
-
+      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("BLTouch Deploy Failed");
+      probe.probe_error_stop();            // Something is wrong, needs action, but not too bad, allow restart
       return true;                         // Tell our caller we goofed in case he cares to know
     }
   }
@@ -153,12 +150,8 @@ bool BLTouch::stow_proc() {
                                            // But one more STOW will catch that
     // Last attempt to STOW
     if (_stow_query_alarm()) {             // so if there is now STILL an ALARM condition:
-
-      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("BLTouch Recovery Failed");
-
-      SERIAL_ERROR_MSG(STR_STOP_BLTOUCH);  // Tell the user something is wrong, needs action
-      stop();                              // but it's not too bad, no need to kill, allow restart
-
+      if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("BLTouch Stow Failed");
+      probe.probe_error_stop();            // Something is wrong, needs action, but not too bad, allow restart
       return true;                         // Tell our caller we goofed in case he cares to know
     }
   }

Marlin/src/gcode/temp/M303.cpp

@@ -71,6 +71,7 @@ void GcodeSuite::M303() {
       case H_CHAMBER: default_temp = PREHEAT_1_TEMP_CHAMBER; break;
     #endif
     default:
+      SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
       SERIAL_ECHOLNPGM(STR_PID_BAD_HEATER_ID);
       TERN_(EXTENSIBLE_UI, ExtUI::onPidTuning(ExtUI::result_t::PID_BAD_EXTRUDER_NUM));
       TERN_(DWIN_LCD_PROUI, DWIN_PidTuning(PID_BAD_EXTRUDER_NUM));

Marlin/src/inc/SanityCheck.h

@@ -2854,10 +2854,8 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
 #if ENABLED(DWIN_CREALITY_LCD)
   #if DISABLED(SDSUPPORT)
     #error "DWIN_CREALITY_LCD requires SDSUPPORT to be enabled."
-  #elif ENABLED(PID_EDIT_MENU)
-    #error "DWIN_CREALITY_LCD does not support PID_EDIT_MENU."
-  #elif ENABLED(PID_AUTOTUNE_MENU)
-    #error "DWIN_CREALITY_LCD does not support PID_AUTOTUNE_MENU."
+  #elif EITHER(PID_EDIT_MENU, PID_AUTOTUNE_MENU)
+    #error "DWIN_CREALITY_LCD does not support PID_EDIT_MENU or PID_AUTOTUNE_MENU."
   #elif ENABLED(LEVEL_BED_CORNERS)
     #error "DWIN_CREALITY_LCD does not support LEVEL_BED_CORNERS."
   #elif BOTH(LCD_BED_LEVELING, PROBE_MANUALLY)
@@ -2866,10 +2864,8 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
 #elif ENABLED(DWIN_LCD_PROUI)
   #if DISABLED(SDSUPPORT)
     #error "DWIN_LCD_PROUI requires SDSUPPORT to be enabled."
-  #elif ENABLED(PID_EDIT_MENU)
-    #error "DWIN_LCD_PROUI does not support PID_EDIT_MENU."
-  #elif ENABLED(PID_AUTOTUNE_MENU)
-    #error "DWIN_LCD_PROUI does not support PID_AUTOTUNE_MENU."
+  #elif EITHER(PID_EDIT_MENU, PID_AUTOTUNE_MENU)
+    #error "DWIN_LCD_PROUI does not support PID_EDIT_MENU or PID_AUTOTUNE_MENU."
   #elif ENABLED(LEVEL_BED_CORNERS)
     #error "DWIN_LCD_PROUI does not support LEVEL_BED_CORNERS."
   #elif BOTH(LCD_BED_LEVELING, PROBE_MANUALLY)

Marlin/src/lcd/menu/menu_advanced.cpp

@@ -211,7 +211,7 @@ void menu_backlash();
 
   // Helpers for editing PID Ki & Kd values
   // grab the PID value out of the temp variable; scale it; then update the PID driver
-  void copy_and_scalePID_i(int16_t e) {
+  void copy_and_scalePID_i(const int8_t e) {
     switch (e) {
       #if ENABLED(PIDTEMPBED)
         case H_BED: thermalManager.temp_bed.pid.Ki = scalePID_i(raw_Ki); break;
@@ -227,7 +227,7 @@ void menu_backlash();
         break;
     }
   }
-  void copy_and_scalePID_d(int16_t e) {
+  void copy_and_scalePID_d(const int8_t e) {
     switch (e) {
       #if ENABLED(PIDTEMPBED)
         case H_BED: thermalManager.temp_bed.pid.Kd = scalePID_d(raw_Kd); break;
@@ -243,30 +243,6 @@ void menu_backlash();
         break;
     }
   }
-
-  #define _DEFINE_PIDTEMP_BASE_FUNCS(N) \
-    void copy_and_scalePID_i_E##N() { copy_and_scalePID_i(N); } \
-    void copy_and_scalePID_d_E##N() { copy_and_scalePID_d(N); }
-
-#else
-
-  #define _DEFINE_PIDTEMP_BASE_FUNCS(N) //
-
-#endif
-
-#if ENABLED(PID_AUTOTUNE_MENU)
-  #define DEFINE_PIDTEMP_FUNCS(N) \
-    _DEFINE_PIDTEMP_BASE_FUNCS(N); \
-    void lcd_autotune_callback_E##N() { _lcd_autotune(heater_id_t(N)); }
-#else
-  #define DEFINE_PIDTEMP_FUNCS(N) _DEFINE_PIDTEMP_BASE_FUNCS(N);
-#endif
-
-#if HAS_HOTEND
-  DEFINE_PIDTEMP_FUNCS(0);
-  #if ENABLED(PID_PARAMS_PER_HOTEND)
-    REPEAT_S(1, HOTENDS, DEFINE_PIDTEMP_FUNCS)
-  #endif
 #endif
 
 #if BOTH(AUTOTEMP, HAS_TEMP_HOTEND) || EITHER(PID_AUTOTUNE_MENU, PID_EDIT_MENU)
@@ -281,6 +257,7 @@ void menu_backlash();
   void menu_advanced_temperature() {
     START_MENU();
     BACK_ITEM(MSG_ADVANCED_SETTINGS);
+
     //
     // Autotemp, Min, Max, Fact
     //
@@ -300,14 +277,7 @@ void menu_backlash();
     // PID-P E5, PID-I E5, PID-D E5, PID-C E5, PID Autotune E5
     //
 
-    #if ENABLED(PID_EDIT_MENU)
-      #define _PID_EDIT_ITEMS_TMPL(N,T) \
-        raw_Ki = unscalePID_i(T.pid.Ki); \
-        raw_Kd = unscalePID_d(T.pid.Kd); \
-        EDIT_ITEM_FAST_N(float41sign, N, MSG_PID_P_E, &T.pid.Kp, 1, 9990); \
-        EDIT_ITEM_FAST_N(float52sign, N, MSG_PID_I_E, &raw_Ki, 0.01f, 9990, []{ copy_and_scalePID_i(N); }); \
-        EDIT_ITEM_FAST_N(float41sign, N, MSG_PID_D_E, &raw_Kd, 1, 9990, []{ copy_and_scalePID_d(N); })
-
+    #if BOTH(PIDTEMP, PID_EDIT_MENU)
       #define __PID_HOTEND_MENU_ITEMS(N) \
         raw_Ki = unscalePID_i(PID_PARAM(Ki, N)); \
         raw_Kd = unscalePID_d(PID_PARAM(Kd, N)); \
@@ -337,17 +307,28 @@ void menu_backlash();
 
     #endif
 
-    #if ENABLED(PID_AUTOTUNE_MENU)
-      #define HOTEND_PID_EDIT_MENU_ITEMS(N) \
-        _HOTEND_PID_EDIT_MENU_ITEMS(N); \
-        EDIT_ITEM_FAST_N(int3, N, MSG_PID_AUTOTUNE_E, &autotune_temp[N], 150, thermalManager.hotend_max_target(N), []{ _lcd_autotune(heater_id_t(MenuItemBase::itemIndex)); });
-    #else
-      #define HOTEND_PID_EDIT_MENU_ITEMS(N) _HOTEND_PID_EDIT_MENU_ITEMS(N);
+    #if ENABLED(PID_EDIT_MENU) && EITHER(PIDTEMPBED, PIDTEMPCHAMBER)
+      #define _PID_EDIT_ITEMS_TMPL(N,T) \
+        raw_Ki = unscalePID_i(T.pid.Ki); \
+        raw_Kd = unscalePID_d(T.pid.Kd); \
+        EDIT_ITEM_FAST_N(float41sign, N, MSG_PID_P_E, &T.pid.Kp, 1, 9990); \
+        EDIT_ITEM_FAST_N(float52sign, N, MSG_PID_I_E, &raw_Ki, 0.01f, 9990, []{ copy_and_scalePID_i(N); }); \
+        EDIT_ITEM_FAST_N(float41sign, N, MSG_PID_D_E, &raw_Kd, 1, 9990, []{ copy_and_scalePID_d(N); })
     #endif
 
-    HOTEND_PID_EDIT_MENU_ITEMS(0);
-    #if ENABLED(PID_PARAMS_PER_HOTEND)
-      REPEAT_S(1, HOTENDS, HOTEND_PID_EDIT_MENU_ITEMS)
+    #if ENABLED(PIDTEMP)
+      #if ENABLED(PID_AUTOTUNE_MENU)
+        #define HOTEND_PID_EDIT_MENU_ITEMS(N) \
+          _HOTEND_PID_EDIT_MENU_ITEMS(N); \
+          EDIT_ITEM_FAST_N(int3, N, MSG_PID_AUTOTUNE_E, &autotune_temp[N], 150, thermalManager.hotend_max_target(N), []{ _lcd_autotune(heater_id_t(MenuItemBase::itemIndex)); });
+      #else
+        #define HOTEND_PID_EDIT_MENU_ITEMS(N) _HOTEND_PID_EDIT_MENU_ITEMS(N);
+      #endif
+
+      HOTEND_PID_EDIT_MENU_ITEMS(0);
+      #if ENABLED(PID_PARAMS_PER_HOTEND)
+        REPEAT_S(1, HOTENDS, HOTEND_PID_EDIT_MENU_ITEMS);
+      #endif
     #endif
 
     #if ENABLED(PIDTEMPBED)

Marlin/src/module/probe.cpp

@@ -415,6 +415,21 @@ FORCE_INLINE void probe_specific_action(const bool deploy) {
 
 #endif
 
+/**
+ * Print an error and stop()
+ */
+void Probe::probe_error_stop() {
+  SERIAL_ERROR_START();
+  SERIAL_ECHOPGM(STR_STOP_PRE);
+  #if EITHER(Z_PROBE_SLED, Z_PROBE_ALLEN_KEY)
+    SERIAL_ECHOPGM(STR_STOP_UNHOMED);
+  #elif ENABLED(BLTOUCH)
+    SERIAL_ECHOPGM(STR_STOP_BLTOUCH);
+  #endif
+  SERIAL_ECHOLNPGM(STR_STOP_POST);
+  stop();
+}
+
 /**
  * Attempt to deploy or stow the probe
  *
@@ -443,8 +458,7 @@ bool Probe::set_deployed(const bool deploy) {
 
   #if EITHER(Z_PROBE_SLED, Z_PROBE_ALLEN_KEY)
     if (homing_needed_error(TERN_(Z_PROBE_SLED, _BV(X_AXIS)))) {
-      SERIAL_ERROR_MSG(STR_STOP_UNHOMED);
-      stop();
+      probe_error_stop();
       return true;
     }
   #endif
@@ -484,15 +498,12 @@ bool Probe::set_deployed(const bool deploy) {
 }
 
 /**
- * @brief Used by run_z_probe to do a single Z probe move.
+ * @brief Move down until the probe triggers or the low limit is reached
+ *        Used by run_z_probe to do a single Z probe move.
  *
  * @param  z        Z destination
  * @param  fr_mm_s  Feedrate in mm/s
  * @return true to indicate an error
- */
-
-/**
- * @brief Move down until the probe triggers or the low limit is reached
  *
  * @details Used by run_z_probe to get each bed Z height measurement.
  *          Sets current_position.z to the height where the probe triggered

Marlin/src/module/probe.h

@@ -78,6 +78,8 @@ public:
       static void preheat_for_probing(const celsius_t hotend_temp, const celsius_t bed_temp);
     #endif
 
+    static void probe_error_stop();
+
     static bool set_deployed(const bool deploy);
 
     #if IS_KINEMATIC

Marlin/src/module/temperature.cpp

@@ -638,6 +638,7 @@ volatile bool Temperature::raw_temps_ready = false;
     TERN_(DWIN_LCD_PROUI, DWIN_PidTuning(isbed ? PID_BED_START : PID_EXTR_START));
 
     if (target > GHV(CHAMBER_MAX_TARGET, BED_MAX_TARGET, temp_range[heater_id].maxtemp - (HOTEND_OVERSHOOT))) {
+      SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
       SERIAL_ECHOLNPGM(STR_PID_TEMP_TOO_HIGH);
       TERN_(EXTENSIBLE_UI, ExtUI::onPidTuning(ExtUI::result_t::PID_TEMP_TOO_HIGH));
       TERN_(DWIN_LCD_PROUI, DWIN_PidTuning(PID_TEMP_TOO_HIGH));
@@ -645,6 +646,7 @@ volatile bool Temperature::raw_temps_ready = false;
       return;
     }
 
+    SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
     SERIAL_ECHOLNPGM(STR_PID_AUTOTUNE_START);
 
     disable_all_heaters();
@@ -660,10 +662,11 @@ volatile bool Temperature::raw_temps_ready = false;
 
     TERN_(NO_FAN_SLOWING_IN_PID_TUNING, adaptive_fan_slowing = false);
 
-    // PID Tuning loop
-    wait_for_heatup = true; // Can be interrupted with M108
     LCD_MESSAGE(MSG_HEATING);
-    while (wait_for_heatup) {
+
+    // PID Tuning loop
+    wait_for_heatup = true;
+    while (wait_for_heatup) { // Can be interrupted with M108
 
       const millis_t ms = millis();
 
@@ -729,6 +732,7 @@ volatile bool Temperature::raw_temps_ready = false;
         #define MAX_OVERSHOOT_PID_AUTOTUNE 30
       #endif
       if (current_temp > target + MAX_OVERSHOOT_PID_AUTOTUNE) {
+        SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
         SERIAL_ECHOLNPGM(STR_PID_TEMP_TOO_HIGH);
         TERN_(EXTENSIBLE_UI, ExtUI::onPidTuning(ExtUI::result_t::PID_TEMP_TOO_HIGH));
         TERN_(DWIN_LCD_PROUI, DWIN_PidTuning(PID_TEMP_TOO_HIGH));
@@ -771,11 +775,13 @@ volatile bool Temperature::raw_temps_ready = false;
         TERN_(DWIN_LCD_PROUI, DWIN_PidTuning(PID_TUNING_TIMEOUT));
         TERN_(EXTENSIBLE_UI, ExtUI::onPidTuning(ExtUI::result_t::PID_TUNING_TIMEOUT));
         TERN_(HOST_PROMPT_SUPPORT, hostui.notify(GET_TEXT_F(MSG_PID_TIMEOUT)));
+        SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
         SERIAL_ECHOLNPGM(STR_PID_TIMEOUT);
         break;
       }
 
       if (cycles > ncycles && cycles > 2) {
+        SERIAL_ECHOPGM(STR_PID_AUTOTUNE);
         SERIAL_ECHOLNPGM(STR_PID_AUTOTUNE_FINISHED);
         TERN_(HOST_PROMPT_SUPPORT, hostui.notify(GET_TEXT_F(MSG_PID_AUTOTUNE_DONE)));
 
@@ -875,7 +881,6 @@ volatile bool Temperature::raw_temps_ready = false;
     MPC_t& constants = hotend.constants;
 
     // move to center of bed, just above bed height and cool with max fan
-    SERIAL_ECHOLNPGM("Moving to tuning position");
     TERN_(HAS_FAN, zero_fan_speeds());
     disable_all_heaters();
     TERN_(HAS_FAN, set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 255));
@@ -902,6 +907,7 @@ volatile bool Temperature::raw_temps_ready = false;
         next_test_ms += 10000UL;
       }
     }
+
     TERN_(HAS_FAN, set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 0));
     TERN_(HAS_FAN, planner.sync_fan_speeds(fan_speed));
 
@@ -909,8 +915,7 @@ volatile bool Temperature::raw_temps_ready = false;
 
     SERIAL_ECHOLNPGM("Heating to 200C");
     hotend.soft_pwm_amount = MPC_MAX >> 1;
-    const millis_t heat_start_time = ms;
-    next_test_ms = ms;
+    const millis_t heat_start_time = next_test_ms = ms;
     celsius_float_t temp_samples[16];
     uint8_t sample_count = 0;
     uint16_t sample_distance = 1;
@@ -941,7 +946,7 @@ volatile bool Temperature::raw_temps_ready = false;
     }
     hotend.soft_pwm_amount = 0;
 
-    // calculate physical constants from three equally spaced samples
+    // Calculate physical constants from three equally-spaced samples
     sample_count = (sample_count + 1) / 2 * 2 - 1;
     const float t1 = temp_samples[0],
                 t2 = temp_samples[(sample_count - 1) >> 1],
@@ -957,14 +962,13 @@ volatile bool Temperature::raw_temps_ready = false;
     hotend.modeled_block_temp = asymp_temp + (ambient_temp - asymp_temp) * exp(-block_responsiveness * (ms - heat_start_time) / 1000.0f);
     hotend.modeled_sensor_temp = current_temp;
 
-    // let the system stabilise under MPC control then get a better measure of ambient loss without and with fan
+    // Allow the system to stabilize under MPC, then get a better measure of ambient loss with and without fan
     SERIAL_ECHOLNPGM("Measuring ambient heatloss at target ", hotend.modeled_block_temp);
     hotend.target = hotend.modeled_block_temp;
     next_test_ms = ms + MPC_dT * 1000;
-    constexpr millis_t settle_time = 20000UL,
-                       test_length = 20000UL;
+    constexpr millis_t settle_time = 20000UL, test_duration = 20000UL;
     millis_t settle_end_ms = ms + settle_time,
-             test_end_ms = settle_end_ms + test_length;
+             test_end_ms = settle_end_ms + test_duration;
     float total_energy_fan0 = 0.0f;
     #if HAS_FAN
       bool fan0_done = false;
@@ -987,7 +991,7 @@ volatile bool Temperature::raw_temps_ready = false;
             set_fan_speed(ANY(MPC_FAN_0_ALL_HOTENDS, MPC_FAN_0_ACTIVE_HOTEND) ? 0 : active_extruder, 255);
             planner.sync_fan_speeds(fan_speed);
             settle_end_ms = ms + settle_time;
-            test_end_ms = settle_end_ms + test_length;
+            test_end_ms = settle_end_ms + test_duration;
             fan0_done = true;
           }
           else if (ELAPSED(ms, settle_end_ms) && !ELAPSED(ms, test_end_ms))
@@ -1005,11 +1009,11 @@ volatile bool Temperature::raw_temps_ready = false;
       }
     }
 
-    const float power_fan0 = total_energy_fan0 * 1000 / test_length;
+    const float power_fan0 = total_energy_fan0 * 1000 / test_duration;
     constants.ambient_xfer_coeff_fan0 = power_fan0 / (hotend.target - ambient_temp);
 
     #if HAS_FAN
-      const float power_fan255 = total_energy_fan255 * 1000 / test_length,
+      const float power_fan255 = total_energy_fan255 * 1000 / test_duration,
                   ambient_xfer_coeff_fan255 = power_fan255 / (hotend.target - ambient_temp);
       constants.fan255_adjustment = ambient_xfer_coeff_fan255 - constants.ambient_xfer_coeff_fan0;
     #endif
@@ -1371,8 +1375,8 @@ void Temperature::min_temp_error(const heater_id_t heater_id) {
       #endif
 
     #elif ENABLED(MPCTEMP)
-      MPCHeaterInfo& hotend = temp_hotend[ee];
-      MPC_t& constants = hotend.constants;
+      MPCHeaterInfo &hotend = temp_hotend[ee];
+      MPC_t &constants = hotend.constants;
 
       // At startup, initialize modeled temperatures
       if (isnan(hotend.modeled_block_temp)) {