🐛 Fix AUTOTEMP bug (thermal runaway) (#23025)

Regression from 9823a37
MarlinFirmware · Dec 25, 2021 · 2142e1d · 2142e1d
1 parent 8d21ea5
commit 2142e1d
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Showing 2 changed files with 2 additions and 2 deletions.
diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
@@ -414,7 +414,7 @@
  */
 #define AUTOTEMP
 #if ENABLED(AUTOTEMP)
-  #define AUTOTEMP_OLDWEIGHT    0.98
+  #define AUTOTEMP_OLDWEIGHT    0.98  // Factor used to weight previous readings (0.0 < value < 1.0)
   // Turn on AUTOTEMP on M104/M109 by default using proportions set here
   //#define AUTOTEMP_PROPORTIONAL
   #if ENABLED(AUTOTEMP_PROPORTIONAL)

diff --git a/Marlin/src/module/planner.cpp b/Marlin/src/module/planner.cpp
@@ -1457,7 +1457,7 @@ void Planner::check_axes_activity() {
 
     float t = autotemp_min + high * autotemp_factor;
     LIMIT(t, autotemp_min, autotemp_max);
-    if (t < oldt) t *= (1.0f - (AUTOTEMP_OLDWEIGHT)) + oldt * (AUTOTEMP_OLDWEIGHT);
+    if (t < oldt) t = t * (1.0f - (AUTOTEMP_OLDWEIGHT)) + oldt * (AUTOTEMP_OLDWEIGHT);
     oldt = t;
     thermalManager.setTargetHotend(t, active_extruder);
   }