Merge pull request #4933 from thinkyhead/rc_drop_pid_func_range

Squashed - Removal of PID functional range

Marlin/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active); 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/Cartesio/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/Felix/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Felix 2.0+ electronics with v4 Hotend

Marlin/example_configurations/Felix/DUAL/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Felix 2.0+ electronics with v4 Hotend

Marlin/example_configurations/Hephestos/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Hephestos i3

Marlin/example_configurations/Hephestos_2/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 250  // If the temperature difference between the target temperature and the actual temperature
-                                    // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Tuned PID values using M303

Marlin/example_configurations/K8200/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/K8400/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/K8400/Dual-head/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/RepRapWorld/Megatronics/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/RigidBot/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/SCARA/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 20 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Merlin Hotend: From Autotune

Marlin/example_configurations/TAZ4/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 70 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX 74 // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX 74 // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 16 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/WITBOX/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Witbox

Marlin/example_configurations/adafruit/ST7565/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/delta/biv2.5/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/delta/generic/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/delta/kossel_mini/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/delta/kossel_pro/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX  125 // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX  125 // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 50 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // Kossel Pro

Marlin/example_configurations/delta/kossel_xl/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/makibox/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/example_configurations/tvrrug/Round2/Configuration.h

 // Comment the following line to disable PID and enable bang-bang.
 #define PIDTEMP
 #define BANG_MAX 255 // limits current to nozzle while in bang-bang mode; 255=full current
-#define PID_MAX BANG_MAX // limits current to nozzle while PID is active (see PID_FUNCTIONAL_RANGE below); 255=full current
+#define PID_MAX BANG_MAX // limits current to nozzle while PID is active; 255=full current
 #if ENABLED(PIDTEMP)
   //#define PID_AUTOTUNE_MENU // Add PID Autotune to the LCD "Temperature" menu to run M303 and apply the result.
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define SLOW_PWM_HEATERS // PWM with very low frequency (roughly 0.125Hz=8s) and minimum state time of approximately 1s useful for heaters driven by a relay
   //#define PID_PARAMS_PER_HOTEND // Uses separate PID parameters for each extruder (useful for mismatched extruders)
                                   // Set/get with gcode: M301 E[extruder number, 0-2]
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
-                                  // is more than PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define K1 0.95 //smoothing factor within the PID
 
   // If you are using a pre-configured hotend then you can use one of the value sets by uncommenting it

Marlin/temperature.cpp

   #endif
 
   float Temperature::pid_error[HOTENDS];
-  bool Temperature::pid_reset[HOTENDS];
 #endif
 
 #if ENABLED(PIDTEMPBED)
 #endif
 
 #if HAS_PID_HEATING
-
   void Temperature::PID_autotune(float temp, int hotend, int ncycles, bool set_result/*=false*/) {
     float input = 0.0;
     int cycles = 0;
 
     #if HAS_PID_FOR_BOTH
       if (hotend < 0)
-        soft_pwm_bed = bias = d = (MAX_BED_POWER) / 2;
+        soft_pwm_bed = bias = d = (MAX_BED_POWER) >> 1;
       else
-        soft_pwm[hotend] = bias = d = (PID_MAX) / 2;
+        soft_pwm[hotend] = bias = d = (PID_MAX) >> 1;
     #elif ENABLED(PIDTEMP)
-      soft_pwm[hotend] = bias = d = (PID_MAX) / 2;
+      soft_pwm[hotend] = bias = d = (PID_MAX) >> 1;
     #else
-      soft_pwm_bed = bias = d = (MAX_BED_POWER) / 2;
+      soft_pwm_bed = bias = d = (MAX_BED_POWER) >> 1;
     #endif
 
     wait_for_heatup = true;
 }
 
 #if HAS_AUTO_FAN
-
   void Temperature::checkExtruderAutoFans() {
     const int8_t fanPin[] = { EXTRUDER_0_AUTO_FAN_PIN, EXTRUDER_1_AUTO_FAN_PIN, EXTRUDER_2_AUTO_FAN_PIN, EXTRUDER_3_AUTO_FAN_PIN };
     const int fanBit[] = {
   #endif
   float pid_output;
   #if ENABLED(PIDTEMP)
-    #if DISABLED(PID_OPENLOOP)
+    #if ENABLED(PID_OPENLOOP)
+      pid_output = constrain(target_temperature[HOTEND_INDEX], 0, PID_MAX);
+    #else
       pid_error[HOTEND_INDEX] = target_temperature[HOTEND_INDEX] - current_temperature[HOTEND_INDEX];
       dTerm[HOTEND_INDEX] = K2 * PID_PARAM(Kd, HOTEND_INDEX) * (current_temperature[HOTEND_INDEX] - temp_dState[HOTEND_INDEX]) + K1 * dTerm[HOTEND_INDEX];
       temp_dState[HOTEND_INDEX] = current_temperature[HOTEND_INDEX];
-      if (pid_error[HOTEND_INDEX] > PID_FUNCTIONAL_RANGE) {
-        pid_output = BANG_MAX;
-        pid_reset[HOTEND_INDEX] = true;
-      }
-      else if (pid_error[HOTEND_INDEX] < -(PID_FUNCTIONAL_RANGE) || target_temperature[HOTEND_INDEX] == 0) {
+      if (target_temperature[HOTEND_INDEX] == 0) {
         pid_output = 0;
-        pid_reset[HOTEND_INDEX] = true;
+        temp_iState[HOTEND_INDEX] = 0.0;
       }
       else {
-        if (pid_reset[HOTEND_INDEX]) {
-          temp_iState[HOTEND_INDEX] = 0.0;
-          pid_reset[HOTEND_INDEX] = false;
-        }
         pTerm[HOTEND_INDEX] = PID_PARAM(Kp, HOTEND_INDEX) * pid_error[HOTEND_INDEX];
         temp_iState[HOTEND_INDEX] += pid_error[HOTEND_INDEX];
         iTerm[HOTEND_INDEX] = PID_PARAM(Ki, HOTEND_INDEX) * temp_iState[HOTEND_INDEX];
           pid_output = 0;
         }
       }
-    #else
-      pid_output = constrain(target_temperature[HOTEND_INDEX], 0, PID_MAX);
     #endif //PID_OPENLOOP
 
     #if ENABLED(PID_DEBUG)
       setPwmFrequency(FAN_PIN, 1); // No prescaling. Pwm frequency = F_CPU/256/8
     #endif
     #if ENABLED(FAN_SOFT_PWM)
-      soft_pwm_fan[0] = fanSpeedSoftPwm[0] / 2;
+      soft_pwm_fan[0] = fanSpeedSoftPwm[0] >> 1;
     #endif
   #endif
 
       setPwmFrequency(FAN1_PIN, 1); // No prescaling. Pwm frequency = F_CPU/256/8
     #endif
     #if ENABLED(FAN_SOFT_PWM)
-      soft_pwm_fan[1] = fanSpeedSoftPwm[1] / 2;
+      soft_pwm_fan[1] = fanSpeedSoftPwm[1] >> 1;
     #endif
   #endif
 
       setPwmFrequency(FAN2_PIN, 1); // No prescaling. Pwm frequency = F_CPU/256/8
     #endif
     #if ENABLED(FAN_SOFT_PWM)
-      soft_pwm_fan[2] = fanSpeedSoftPwm[2] / 2;
+      soft_pwm_fan[2] = fanSpeedSoftPwm[2] >> 1;
     #endif
   #endif
 
 
       #if ENABLED(FAN_SOFT_PWM)
         #if HAS_FAN0
-          soft_pwm_fan[0] = fanSpeedSoftPwm[0] / 2;
+          soft_pwm_fan[0] = fanSpeedSoftPwm[0] >> 1;
           WRITE_FAN(soft_pwm_fan[0] > 0 ? 1 : 0);
         #endif
         #if HAS_FAN1
-          soft_pwm_fan[1] = fanSpeedSoftPwm[1] / 2;
+          soft_pwm_fan[1] = fanSpeedSoftPwm[1] >> 1;
           WRITE_FAN1(soft_pwm_fan[1] > 0 ? 1 : 0);
         #endif
         #if HAS_FAN2
-          soft_pwm_fan[2] = fanSpeedSoftPwm[2] / 2;
+          soft_pwm_fan[2] = fanSpeedSoftPwm[2] >> 1;
           WRITE_FAN2(soft_pwm_fan[2] > 0 ? 1 : 0);
         #endif
       #endif
     #if ENABLED(FAN_SOFT_PWM)
       if (pwm_count == 0) {
         #if HAS_FAN0
-          soft_pwm_fan[0] = fanSpeedSoftPwm[0] / 2;
+          soft_pwm_fan[0] = fanSpeedSoftPwm[0] >> 1;
           WRITE_FAN(soft_pwm_fan[0] > 0 ? 1 : 0);
         #endif
         #if HAS_FAN1
-          soft_pwm_fan[1] = fanSpeedSoftPwm[1] / 2;
+          soft_pwm_fan[1] = fanSpeedSoftPwm[1] >> 1;
           WRITE_FAN1(soft_pwm_fan[1] > 0 ? 1 : 0);
         #endif
         #if HAS_FAN2
-          soft_pwm_fan[2] = fanSpeedSoftPwm[2] / 2;
+          soft_pwm_fan[2] = fanSpeedSoftPwm[2] >> 1;
           WRITE_FAN2(soft_pwm_fan[2] > 0 ? 1 : 0);
         #endif
       }

Marlin/temperature.h

       #endif
 
       static float pid_error[HOTENDS];
-      static bool pid_reset[HOTENDS];
     #endif
 
     #if ENABLED(PIDTEMPBED)