Merge pull request #4573 from thinkyhead/rc_mintemp_bed_later

Throw MINTEMP BED error only if heating

Marlin/temperature.cpp

   #endif
 }
 
-void Temperature::max_temp_error(uint8_t e) {
-  #if HOTENDS == 1
-    UNUSED(e);
+void Temperature::max_temp_error(int8_t e) {
+  #if HAS_TEMP_BED
+    _temp_error(e, PSTR(MSG_T_MAXTEMP), e >= 0 ? PSTR(MSG_ERR_MAXTEMP) : PSTR(MSG_ERR_MAXTEMP_BED));
+  #else
+    _temp_error(HOTEND_INDEX, PSTR(MSG_T_MAXTEMP), PSTR(MSG_ERR_MAXTEMP));
+    #if HOTENDS == 1
+      UNUSED(e);
+    #endif
   #endif
-  _temp_error(HOTEND_INDEX, PSTR(MSG_T_MAXTEMP), PSTR(MSG_ERR_MAXTEMP));
 }
-void Temperature::min_temp_error(uint8_t e) {
-  #if HOTENDS == 1
-    UNUSED(e);
+void Temperature::min_temp_error(int8_t e) {
+  #if HAS_TEMP_BED
+    _temp_error(e, PSTR(MSG_T_MINTEMP), e >= 0 ? PSTR(MSG_ERR_MINTEMP) : PSTR(MSG_ERR_MINTEMP_BED));
+  #else
+    _temp_error(HOTEND_INDEX, PSTR(MSG_T_MINTEMP), PSTR(MSG_ERR_MINTEMP));
+    #if HOTENDS == 1
+      UNUSED(e);
+    #endif
   #endif
-  _temp_error(HOTEND_INDEX, PSTR(MSG_T_MINTEMP), PSTR(MSG_ERR_MINTEMP));
 }
 
 float Temperature::get_pid_output(int e) {
   updateTemperaturesFromRawValues(); // also resets the watchdog
 
   #if ENABLED(HEATER_0_USES_MAX6675)
-    float ct = current_temperature[0];
-    if (ct > min(HEATER_0_MAXTEMP, 1023)) max_temp_error(0);
-    if (ct < max(HEATER_0_MINTEMP, 0.01)) min_temp_error(0);
+    if (current_temperature[0] > min(HEATER_0_MAXTEMP, 1023)) max_temp_error(0);
+    if (current_temperature[0] < max(HEATER_0_MINTEMP, 0.01)) min_temp_error(0);
   #endif
 
   #if (ENABLED(THERMAL_PROTECTION_HOTENDS) && WATCH_TEMP_PERIOD > 0) || (ENABLED(THERMAL_PROTECTION_BED) && WATCH_BED_TEMP_PERIOD > 0) || DISABLED(PIDTEMPBED) || HAS_AUTO_FAN
       #else
         #define GEBED >=
       #endif
-      if (current_temperature_bed_raw GEBED bed_maxttemp_raw) _temp_error(-1, PSTR(MSG_T_MAXTEMP), PSTR(MSG_ERR_MAXTEMP_BED));
-      if (bed_minttemp_raw GEBED current_temperature_bed_raw) _temp_error(-1, PSTR(MSG_T_MINTEMP), PSTR(MSG_ERR_MINTEMP_BED));
+      if (current_temperature_bed_raw GEBED bed_maxttemp_raw) max_temp_error(-1);
+      if (bed_minttemp_raw GEBED current_temperature_bed_raw && target_temperature_bed > 0.0f) min_temp_error(-1);
     #endif
 
   } // temp_count >= OVERSAMPLENR

Marlin/temperature.h

     #endif
 
     static void _temp_error(int e, const char* serial_msg, const char* lcd_msg);
-    static void min_temp_error(uint8_t e);
-    static void max_temp_error(uint8_t e);
+    static void min_temp_error(int8_t e);
+    static void max_temp_error(int8_t e);
 
     #if ENABLED(THERMAL_PROTECTION_HOTENDS) || HAS_THERMALLY_PROTECTED_BED