Add 4th extruder

10 years ago · 0ebf896070
parent 54d5b52a2e
commit 0ebf896070
16 changed files with 611 additions and 216 deletions
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@ -44,7 +44,7 @@
 // The following define selects which electronics board you have.
 // Please choose the name from boards.h that matches your setup
 #ifndef MOTHERBOARD
-  #define MOTHERBOARD BOARD_ULTIMAKER
+  #define MOTHERBOARD BOARD_AZTEEG_X3_PRO
 #endif

 // Define this to set a custom name for your generic Mendel,
@ -104,9 +104,10 @@
 // 147 is Pt100 with 4k7 pullup
 // 110 is Pt100 with 1k pullup (non standard)

-#define TEMP_SENSOR_0 -1
-#define TEMP_SENSOR_1 -1
+#define TEMP_SENSOR_0 1
+#define TEMP_SENSOR_1 0
 #define TEMP_SENSOR_2 0
+#define TEMP_SENSOR_3 0
 #define TEMP_SENSOR_BED 0

 // This makes temp sensor 1 a redundant sensor for sensor 0. If the temperatures difference between these sensors is to high the print will be aborted.
@ -121,20 +122,22 @@
 // The minimal temperature defines the temperature below which the heater will not be enabled It is used
 // to check that the wiring to the thermistor is not broken.
 // Otherwise this would lead to the heater being powered on all the time.
-#define HEATER_0_MINTEMP 5
-#define HEATER_1_MINTEMP 5
-#define HEATER_2_MINTEMP 5
-#define BED_MINTEMP 5
+#define HEATER_0_MINTEMP 5 // degC
+#define HEATER_1_MINTEMP 5 // degC
+#define HEATER_2_MINTEMP 5 // degC
+#define HEATER_3_MINTEMP 5 // degC
+#define BED_MINTEMP      5 // degC

 // When temperature exceeds max temp, your heater will be switched off.
 // This feature exists to protect your hotend from overheating accidentally, but *NOT* from thermistor short/failure!
 // You should use MINTEMP for thermistor short/failure protection.
-#define HEATER_0_MAXTEMP 275
-#define HEATER_1_MAXTEMP 275
-#define HEATER_2_MAXTEMP 275
-#define BED_MAXTEMP 150
+#define HEATER_0_MAXTEMP 275 // degC
+#define HEATER_1_MAXTEMP 275 // degC
+#define HEATER_2_MAXTEMP 275 // degC
+#define HEATER_3_MAXTEMP 275 // degC
+#define BED_MAXTEMP      150 // degC

-// If your bed has low resistance e.g. .6 ohm and throws the fuse you can duty cycle it to reduce the
+// If your bed has low resistance e.g. 0.6 ohm and throws the fuse you can duty cycle it to reduce the
 // average current. The value should be an integer and the heat bed will be turned on for 1 interval of
 // HEATER_BED_DUTY_CYCLE_DIVIDER intervals.
 //#define HEATER_BED_DUTY_CYCLE_DIVIDER 4
@ -221,7 +224,7 @@
 //if PREVENT_DANGEROUS_EXTRUDE is on, you can still disable (uncomment) very long bits of extrusion separately.
 #define PREVENT_LENGTHY_EXTRUDE

-#define EXTRUDE_MINTEMP 170
+#define EXTRUDE_MINTEMP 170 // degC
 #define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.

 /*================== Thermal Runaway Protection ==============================
@ -325,6 +328,7 @@ const bool Z_MAX_ENDSTOP_INVERTING = true; // set to true to invert the logic of
 #define INVERT_E0_DIR false   // for direct drive extruder v9 set to true, for geared extruder set to false
 #define INVERT_E1_DIR false    // for direct drive extruder v9 set to true, for geared extruder set to false
 #define INVERT_E2_DIR false   // for direct drive extruder v9 set to true, for geared extruder set to false
+#define INVERT_E3_DIR false   // for direct drive extruder v9 set to true, for geared extruder set to false

 // ENDSTOP SETTINGS:
 // Sets direction of endstops when homing; 1=MAX, -1=MIN
--- a/Marlin/ConfigurationStore.cpp
+++ b/Marlin/ConfigurationStore.cpp
@ -77,7 +77,7 @@ void Config_StoreSettings()
  EEPROM_WRITE_VAR(i,zprobe_zoffset);
  #ifdef PIDTEMP
    float dummy = 0.0f;
-    for (int e = 0; e < 3; e++)
+    for (int e = 0; e < 4; e++)
 	{
 	  if (e < EXTRUDERS)
 	  {
@ -132,12 +132,15 @@ void Config_StoreSettings()
  // Save filament sizes
  EEPROM_WRITE_VAR(i, volumetric_enabled);
  EEPROM_WRITE_VAR(i, filament_size[0]);
-  #if EXTRUDERS > 1
+#if EXTRUDERS > 1
  EEPROM_WRITE_VAR(i, filament_size[1]);
-  #if EXTRUDERS > 2
+#if EXTRUDERS > 2
  EEPROM_WRITE_VAR(i, filament_size[2]);
-  #endif//EXTRUDERS > 2
-  #endif//EXTRUDERS > 1
+#if EXTRUDERS > 3
+  EEPROM_WRITE_VAR(i, filament_size[3]);
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
  
  char ver2[4]=EEPROM_VERSION;
  i=EEPROM_OFFSET;
@ -280,8 +283,13 @@ SERIAL_ECHOLNPGM("Scaling factors:");
 		SERIAL_ECHO_START;
        SERIAL_ECHOPAIR("   M200 T2 D", filament_size[2]);
 		SERIAL_ECHOLN("");
-#endif//EXTRUDERS > 2
-#endif//EXTRUDERS > 1
+#if EXTRUDERS > 3
+        SERIAL_ECHO_START;
+        SERIAL_ECHOPAIR("   M200 T3 D", filament_size[3]);
+        SERIAL_ECHOLN("");
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
    } else {
        SERIAL_ECHOLNPGM("Filament settings: Disabled");
    }
@ -336,7 +344,7 @@ void Config_RetrieveSettings()
        EEPROM_READ_VAR(i,zprobe_zoffset);
        #ifdef PIDTEMP
 		float dummy = 0.0f;
-		for (int e = 0; e < 3; e++) // 3 = max extruders supported by marlin
+		for (int e = 0; e < 4; e++) // 4 = max extruders supported by marlin
 		{
 		  if (e < EXTRUDERS)
 		  {
@ -403,8 +411,11 @@ void Config_RetrieveSettings()
 		EEPROM_READ_VAR(i, filament_size[1]);
 #if EXTRUDERS > 2
 		EEPROM_READ_VAR(i, filament_size[2]);
-#endif//EXTRUDERS > 2
-#endif//EXTRUDERS > 1
+#if EXTRUDERS > 3
+    EEPROM_READ_VAR(i, filament_size[3]);
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
 		calculate_volumetric_multipliers();
 		// Call updatePID (similar to when we have processed M301)
 		updatePID();
@ -508,8 +519,11 @@ void Config_ResetDefault()
 	filament_size[1] = DEFAULT_NOMINAL_FILAMENT_DIA;
 #if EXTRUDERS > 2
 	filament_size[2] = DEFAULT_NOMINAL_FILAMENT_DIA;
-#endif//EXTRUDERS > 2
-#endif//EXTRUDERS > 1
+#if EXTRUDERS > 3
+  filament_size[3] = DEFAULT_NOMINAL_FILAMENT_DIA;
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
 	calculate_volumetric_multipliers();

 SERIAL_ECHO_START;
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@ -78,6 +78,7 @@
 #define EXTRUDER_0_AUTO_FAN_PIN -1
 #define EXTRUDER_1_AUTO_FAN_PIN -1
 #define EXTRUDER_2_AUTO_FAN_PIN -1
+#define EXTRUDER_3_AUTO_FAN_PIN -1
 #define EXTRUDER_AUTO_FAN_TEMPERATURE 50
 #define EXTRUDER_AUTO_FAN_SPEED   255  // == full speed

@ -486,6 +487,10 @@ const unsigned int dropsegments=5; //everything with less than this number of st
  #define THERMISTORHEATER_2 TEMP_SENSOR_2
  #define HEATER_2_USES_THERMISTOR
 #endif
+#if TEMP_SENSOR_3 > 0
+  #define THERMISTORHEATER_3 TEMP_SENSOR_3
+  #define HEATER_3_USES_THERMISTOR
+#endif
 #if TEMP_SENSOR_BED > 0
  #define THERMISTORBED TEMP_SENSOR_BED
  #define BED_USES_THERMISTOR
@ -499,6 +504,9 @@ const unsigned int dropsegments=5; //everything with less than this number of st
 #if TEMP_SENSOR_2 == -1
  #define HEATER_2_USES_AD595
 #endif
+#if TEMP_SENSOR_3 == -1
+  #define HEATER_3_USES_AD595
+#endif
 #if TEMP_SENSOR_BED == -1
  #define BED_USES_AD595
 #endif
@ -517,6 +525,10 @@ const unsigned int dropsegments=5; //everything with less than this number of st
  #undef HEATER_2_MINTEMP
  #undef HEATER_2_MAXTEMP
 #endif
+#if TEMP_SENSOR_3 == 0
+  #undef HEATER_3_MINTEMP
+  #undef HEATER_3_MAXTEMP
+#endif
 #if TEMP_SENSOR_BED == 0
  #undef BED_MINTEMP
  #undef BED_MAXTEMP
--- a/Marlin/Marlin.h
+++ b/Marlin/Marlin.h
@ -170,6 +170,13 @@ void manage_inactivity(bool ignore_stepper_queue=false);
  #define disable_e2() /* nothing */
 #endif

+#if (EXTRUDERS > 3) && defined(E3_ENABLE_PIN) && (E3_ENABLE_PIN > -1)
+  #define enable_e3() WRITE(E3_ENABLE_PIN, E_ENABLE_ON)
+  #define disable_e3() WRITE(E3_ENABLE_PIN,!E_ENABLE_ON)
+#else
+  #define enable_e3()  /* nothing */
+  #define disable_e3() /* nothing */
+#endif

 enum AxisEnum {X_AXIS=0, Y_AXIS=1, Z_AXIS=2, E_AXIS=3, X_HEAD=4, Y_HEAD=5};

--- a/Marlin/Marlin_main.cpp
+++ b/Marlin/Marlin_main.cpp
@ -212,6 +212,9 @@ int extruder_multiply[EXTRUDERS] = {100
    , 100
    #if EXTRUDERS > 2
      , 100
+	    #if EXTRUDERS > 3
+      	, 100
+	    #endif
    #endif
  #endif
 };
@ -221,6 +224,9 @@ float filament_size[EXTRUDERS] = { DEFAULT_NOMINAL_FILAMENT_DIA
      , DEFAULT_NOMINAL_FILAMENT_DIA
    #if EXTRUDERS > 2
       , DEFAULT_NOMINAL_FILAMENT_DIA
+      #if EXTRUDERS > 3
+        , DEFAULT_NOMINAL_FILAMENT_DIA
+      #endif
    #endif
  #endif
 };
@ -229,6 +235,9 @@ float volumetric_multiplier[EXTRUDERS] = {1.0
    , 1.0
    #if EXTRUDERS > 2
      , 1.0
+      #if EXTRUDERS > 3
+        , 1.0
+      #endif
    #endif
  #endif
 };
@ -274,6 +283,9 @@ int EtoPPressure=0;
      , false
      #if EXTRUDERS > 2
        , false
+        #if EXTRUDERS > 3
+       	  , false
+      	#endif
      #endif
    #endif
  };
@ -282,6 +294,9 @@ int EtoPPressure=0;
      , false
      #if EXTRUDERS > 2
        , false
+        #if EXTRUDERS > 3
+       	  , false
+      	#endif
      #endif
    #endif
  };
@ -293,7 +308,7 @@ int EtoPPressure=0;
  float retract_recover_length = RETRACT_RECOVER_LENGTH;
  float retract_recover_length_swap = RETRACT_RECOVER_LENGTH_SWAP;
  float retract_recover_feedrate = RETRACT_RECOVER_FEEDRATE;
-#endif
+#endif // FWRETRACT

 #ifdef ULTIPANEL
  #ifdef PS_DEFAULT_OFF
@ -582,8 +597,8 @@ void setup()
      SERIAL_ECHOLNPGM(STRING_CONFIG_H_AUTHOR);
      SERIAL_ECHOPGM("Compiled: ");
      SERIAL_ECHOLNPGM(__DATE__);
-    #endif
-  #endif
+    #endif // STRING_CONFIG_H_AUTHOR
+  #endif // STRING_VERSION_CONFIG_H
  SERIAL_ECHO_START;
  SERIAL_ECHOPGM(MSG_FREE_MEMORY);
  SERIAL_ECHO(freeMemory());
@ -2891,12 +2906,15 @@ Sigma_Exit:
            filament_size[tmp_extruder] = (float)code_value();
            // make sure all extruders have some sane value for the filament size
            filament_size[0] = (filament_size[0] == 0.0 ? DEFAULT_NOMINAL_FILAMENT_DIA : filament_size[0]);
-            #if EXTRUDERS > 1
+#if EXTRUDERS > 1
            filament_size[1] = (filament_size[1] == 0.0 ? DEFAULT_NOMINAL_FILAMENT_DIA : filament_size[1]);
-            #if EXTRUDERS > 2
+#if EXTRUDERS > 2
            filament_size[2] = (filament_size[2] == 0.0 ? DEFAULT_NOMINAL_FILAMENT_DIA : filament_size[2]);
-            #endif
-            #endif
+#if EXTRUDERS > 3
+            filament_size[3] = (filament_size[3] == 0.0 ? DEFAULT_NOMINAL_FILAMENT_DIA : filament_size[3]);
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
            volumetric_enabled = true;
          }
        } else {
@ -3020,23 +3038,29 @@ Sigma_Exit:
          {
            autoretract_enabled=false;
            retracted[0]=false;
-            #if EXTRUDERS > 1
+#if EXTRUDERS > 1
            retracted[1]=false;
-            #endif
-            #if EXTRUDERS > 2
+#endif
+#if EXTRUDERS > 2
            retracted[2]=false;
-            #endif
+#endif
+#if EXTRUDERS > 3
+            retracted[3]=false;
+#endif
          }break;
          case 1: 
          {
            autoretract_enabled=true;
            retracted[0]=false;
-            #if EXTRUDERS > 1
+#if EXTRUDERS > 1
            retracted[1]=false;
-            #endif
-            #if EXTRUDERS > 2
+#endif
+#if EXTRUDERS > 2
            retracted[2]=false;
-            #endif
+#endif
+#if EXTRUDERS > 3
+            retracted[3]=false;
+#endif
          }break;
          default:
            SERIAL_ECHO_START;
@ -4680,7 +4704,10 @@ void calculate_volumetric_multipliers() {
 	volumetric_multiplier[1] = calculate_volumetric_multiplier(filament_size[1]);
 #if EXTRUDERS > 2
 	volumetric_multiplier[2] = calculate_volumetric_multiplier(filament_size[2]);
-#endif
-#endif
+#if EXTRUDERS > 3
+	volumetric_multiplier[3] = calculate_volumetric_multiplier(filament_size[3]);
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
 }

--- a/Marlin/language_en.h
+++ b/Marlin/language_en.h
@ -21,14 +21,16 @@
 #define MSG_PREHEAT_PLA0                    "Preheat PLA 1"
 #define MSG_PREHEAT_PLA1                    "Preheat PLA 2"
 #define MSG_PREHEAT_PLA2                    "Preheat PLA 3"
-#define MSG_PREHEAT_PLA012                  "Preheat PLA All"
+#define MSG_PREHEAT_PLA3                    "Preheat PLA 4"
+#define MSG_PREHEAT_PLA0123                 "Preheat PLA All"
 #define MSG_PREHEAT_PLA_BEDONLY             "Preheat PLA Bed"
 #define MSG_PREHEAT_PLA_SETTINGS            "Preheat PLA conf"
 #define MSG_PREHEAT_ABS                     "Preheat ABS"
 #define MSG_PREHEAT_ABS0                    "Preheat ABS 1"
 #define MSG_PREHEAT_ABS1                    "Preheat ABS 2"
 #define MSG_PREHEAT_ABS2                    "Preheat ABS 3"
-#define MSG_PREHEAT_ABS012                  "Preheat ABS All"
+#define MSG_PREHEAT_ABS3                    "Preheat ABS 4"
+#define MSG_PREHEAT_ABS0123                 "Preheat ABS All"
 #define MSG_PREHEAT_ABS_BEDONLY             "Preheat ABS Bed"
 #define MSG_PREHEAT_ABS_SETTINGS            "Preheat ABS conf"
 #define MSG_COOLDOWN                        "Cooldown"
@ -43,6 +45,7 @@
 #define MSG_MOVE_E                          "Extruder"
 #define MSG_MOVE_E1                         "Extruder2"
 #define MSG_MOVE_E2                         "Extruder3"
+#define MSG_MOVE_E3                         "Extruder4"
 #define MSG_MOVE_01MM                       "Move 0.1mm"
 #define MSG_MOVE_1MM                        "Move 1mm"
 #define MSG_MOVE_10MM                       "Move 10mm"
@ -50,12 +53,14 @@
 #define MSG_NOZZLE                          "Nozzle"
 #define MSG_NOZZLE1                         "Nozzle2"
 #define MSG_NOZZLE2                         "Nozzle3"
+#define MSG_NOZZLE3                         "Nozzle4"
 #define MSG_BED                             "Bed"
 #define MSG_FAN_SPEED                       "Fan speed"
 #define MSG_FLOW                            "Flow"
 #define MSG_FLOW0                           "Flow 0"
 #define MSG_FLOW1                           "Flow 1"
 #define MSG_FLOW2                           "Flow 2"
+#define MSG_FLOW3                           "Flow 3"
 #define MSG_CONTROL                         "Control"
 #define MSG_MIN                             " \002 Min"
 #define MSG_MAX                             " \002 Max"
@ -75,6 +80,10 @@
 #define MSG_PID_I2                          "PID-I E3"
 #define MSG_PID_D2                          "PID-D E3"
 #define MSG_PID_C2                          "PID-C E3"
+#define MSG_PID_P3                          "PID-P E4"
+#define MSG_PID_I3                          "PID-I E4"
+#define MSG_PID_D3                          "PID-D E4"
+#define MSG_PID_C3                          "PID-C E4"
 #define MSG_ACC                             "Accel"
 #define MSG_VXY_JERK                        "Vxy-jerk"
 #define MSG_VZ_JERK                         "Vz-jerk"
@ -99,6 +108,7 @@
 #define MSG_FILAMENT_SIZE_EXTRUDER_0        "Fil. Dia. 1"
 #define MSG_FILAMENT_SIZE_EXTRUDER_1        "Fil. Dia. 2"
 #define MSG_FILAMENT_SIZE_EXTRUDER_2        "Fil. Dia. 3"
+#define MSG_FILAMENT_SIZE_EXTRUDER_3        "Fil. Dia. 4"
 #define MSG_CONTRAST                        "LCD contrast"
 #define MSG_STORE_EPROM                     "Store memory"
 #define MSG_LOAD_EPROM                      "Load memory"
--- a/Marlin/language_it.h
+++ b/Marlin/language_it.h
@ -21,14 +21,16 @@
 #define MSG_PREHEAT_PLA0                    "Preriscalda PLA 1"
 #define MSG_PREHEAT_PLA1                    "Preriscalda PLA 2"
 #define MSG_PREHEAT_PLA2                    "Preriscalda PLA 3"
-#define MSG_PREHEAT_PLA012                  "Prer. PLA Tutto"
+#define MSG_PREHEAT_PLA3                    "Preriscalda PLA 4"
+#define MSG_PREHEAT_PLA0123                 "Prer. PLA Tutto"
 #define MSG_PREHEAT_PLA_BEDONLY             "Prer. PLA Piatto"
 #define MSG_PREHEAT_PLA_SETTINGS            "Config. prer. PLA"
 #define MSG_PREHEAT_ABS                     "Preriscalda ABS"
 #define MSG_PREHEAT_ABS0                    "Preriscalda ABS 1"
 #define MSG_PREHEAT_ABS1                    "Preriscalda ABS 2"
 #define MSG_PREHEAT_ABS2                    "Preriscalda ABS 3"
-#define MSG_PREHEAT_ABS012                  "Prer. ABS Tutto"
+#define MSG_PREHEAT_ABS3                    "Preriscalda ABS 4"
+#define MSG_PREHEAT_ABS0123                 "Prer. ABS Tutto"
 #define MSG_PREHEAT_ABS_BEDONLY             "Prer. ABS Piatto"
 #define MSG_PREHEAT_ABS_SETTINGS            "Config. prer. ABS"
 #define MSG_COOLDOWN                        "Raffredda"
@ -43,6 +45,7 @@
 #define MSG_MOVE_E                          "Estrusore"
 #define MSG_MOVE_E1                         "Estrusore 2"
 #define MSG_MOVE_E2                         "Estrusore 3"
+#define MSG_MOVE_E3                         "Estrusore 4"
 #define MSG_MOVE_01MM                       "Muovi di 0.1mm"
 #define MSG_MOVE_1MM                        "Muovi di   1mm"
 #define MSG_MOVE_10MM                       "Muovi di  10mm"
@ -50,12 +53,14 @@
 #define MSG_NOZZLE                          "Ugello"
 #define MSG_NOZZLE1                         "Ugello2"
 #define MSG_NOZZLE2                         "Ugello3"
+#define MSG_NOZZLE3                         "Ugello4"
 #define MSG_BED                             "Piatto"
 #define MSG_FAN_SPEED                       "Ventola"
 #define MSG_FLOW                            "Flusso"
 #define MSG_FLOW0                           "Flusso 0"
 #define MSG_FLOW1                           "Flusso 1"
 #define MSG_FLOW2                           "Flusso 2"
+#define MSG_FLOW3                           "Flusso 3"
 #define MSG_CONTROL                         "Controllo"
 #define MSG_MIN                             " \002 Min:"
 #define MSG_MAX                             " \002 Max:"
@ -75,6 +80,10 @@
 #define MSG_PID_I2                          "PID-I E3"
 #define MSG_PID_D2                          "PID-D E3"
 #define MSG_PID_C2                          "PID-C E3"
+#define MSG_PID_P3                          "PID-P E4"
+#define MSG_PID_I3                          "PID-I E4"
+#define MSG_PID_D3                          "PID-D E4"
+#define MSG_PID_C3                          "PID-C E4"
 #define MSG_ACC                             "Accel."
 #define MSG_VXY_JERK                        "Vxy-jerk"
 #define MSG_VZ_JERK                         "Vz-jerk"
@ -99,6 +108,7 @@
 #define MSG_FILAMENT_SIZE_EXTRUDER_0        "Diam. filo 1"
 #define MSG_FILAMENT_SIZE_EXTRUDER_1        "Diam. filo 2"
 #define MSG_FILAMENT_SIZE_EXTRUDER_2        "Diam. filo 3"
+#define MSG_FILAMENT_SIZE_EXTRUDER_3        "Diam. filo 4"
 #define MSG_CONTRAST                        "Contrasto LCD"
 #define MSG_STORE_EPROM                     "Salva in EEPROM"
 #define MSG_LOAD_EPROM                      "Carica da EEPROM"
--- a/Marlin/pins.h
+++ b/Marlin/pins.h
@ -2933,6 +2933,12 @@ Fan_2 2
 #endif // CHEAPTRONIC


+#ifndef HEATER_3_PIN
+  #define HEATER_3_PIN -1
+#endif
+#ifndef TEMP_3_PIN
+  #define TEMP_3_PIN -1
+#endif

 #ifndef KNOWN_BOARD
 #error Unknown MOTHERBOARD value in configuration.h
@ -2950,6 +2956,11 @@ Fan_2 2
 #else
  #define _E2_PINS
 #endif
+#if EXTRUDERS > 3
+  #define _E3_PINS E3_STEP_PIN, E3_DIR_PIN, E3_ENABLE_PIN, HEATER_3_PIN,
+#else
+  #define _E3_PINS
+#endif

 #ifdef X_STOP_PIN
  #if X_HOME_DIR < 0
@ -2995,7 +3006,6 @@ Fan_2 2

 #define SENSITIVE_PINS {0, 1, X_STEP_PIN, X_DIR_PIN, X_ENABLE_PIN, X_MIN_PIN, X_MAX_PIN, Y_STEP_PIN, Y_DIR_PIN, Y_ENABLE_PIN, Y_MIN_PIN, Y_MAX_PIN, Z_STEP_PIN, Z_DIR_PIN, Z_ENABLE_PIN, Z_MIN_PIN, Z_MAX_PIN, PS_ON_PIN, \
                        HEATER_BED_PIN, FAN_PIN,                  \
-                        _E0_PINS _E1_PINS _E2_PINS             \
-                        analogInputToDigitalPin(TEMP_0_PIN), analogInputToDigitalPin(TEMP_1_PIN), analogInputToDigitalPin(TEMP_2_PIN), analogInputToDigitalPin(TEMP_BED_PIN) }
-
+                        _E0_PINS _E1_PINS _E2_PINS _E3_PINS           \
+                        analogInputToDigitalPin(TEMP_0_PIN), analogInputToDigitalPin(TEMP_1_PIN), analogInputToDigitalPin(TEMP_2_PIN), analogInputToDigitalPin(TEMP_3_PIN), analogInputToDigitalPin(TEMP_BED_PIN) }
 #endif //__PINS_H
--- a/Marlin/planner.cpp
+++ b/Marlin/planner.cpp
@ -80,7 +80,7 @@ unsigned long axis_steps_per_sqr_second[NUM_AXIS];
 matrix_3x3 plan_bed_level_matrix = {
 	1.0, 0.0, 0.0,
 	0.0, 1.0, 0.0,
-	0.0, 0.0, 1.0,
+	0.0, 0.0, 1.0
 };
 #endif // #ifdef ENABLE_AUTO_BED_LEVELING

@ -96,7 +96,7 @@ float autotemp_factor=0.1;
 bool autotemp_enabled=false;
 #endif

-unsigned char g_uc_extruder_last_move[3] = {0,0,0};
+unsigned char g_uc_extruder_last_move[4] = {0,0,0,0};

 //===========================================================================
 //=================semi-private variables, used in inline  functions    =====
@ -486,6 +486,7 @@ void check_axes_activity()
    disable_e0();
    disable_e1();
    disable_e2(); 
+    disable_e3();
  }
 #if defined(FAN_PIN) && FAN_PIN > -1
  #ifdef FAN_KICKSTART_TIME
@ -672,6 +673,7 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
      if(g_uc_extruder_last_move[0] > 0) g_uc_extruder_last_move[0]--;
      if(g_uc_extruder_last_move[1] > 0) g_uc_extruder_last_move[1]--;
      if(g_uc_extruder_last_move[2] > 0) g_uc_extruder_last_move[2]--;
+      if(g_uc_extruder_last_move[3] > 0) g_uc_extruder_last_move[3]--;
      
      switch(extruder)
      {
@ -681,6 +683,7 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
          
          if(g_uc_extruder_last_move[1] == 0) disable_e1(); 
          if(g_uc_extruder_last_move[2] == 0) disable_e2(); 
+          if(g_uc_extruder_last_move[3] == 0) disable_e3(); 
        break;
        case 1:
          enable_e1(); 
@ -688,6 +691,7 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
          
          if(g_uc_extruder_last_move[0] == 0) disable_e0(); 
          if(g_uc_extruder_last_move[2] == 0) disable_e2(); 
+          if(g_uc_extruder_last_move[3] == 0) disable_e3(); 
        break;
        case 2:
          enable_e2(); 
@ -695,6 +699,15 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
          
          if(g_uc_extruder_last_move[0] == 0) disable_e0(); 
          if(g_uc_extruder_last_move[1] == 0) disable_e1(); 
+          if(g_uc_extruder_last_move[3] == 0) disable_e3(); 
+        break;        
+        case 3:
+          enable_e3(); 
+          g_uc_extruder_last_move[3] = BLOCK_BUFFER_SIZE*2;
+          
+          if(g_uc_extruder_last_move[0] == 0) disable_e0(); 
+          if(g_uc_extruder_last_move[1] == 0) disable_e1(); 
+          if(g_uc_extruder_last_move[2] == 0) disable_e2(); 
        break;        
      }
    }
@ -703,6 +716,7 @@ block->steps_y = labs((target[X_AXIS]-position[X_AXIS]) - (target[Y_AXIS]-positi
      enable_e0();
      enable_e1();
      enable_e2();
+      enable_e3();
    }
  }

@ -866,7 +880,7 @@ Having the real displacement of the head, we can calculate the total movement le
  long min_xy_segment_time =min(max_x_segment_time, max_y_segment_time);
  if(min_xy_segment_time < MAX_FREQ_TIME)
    speed_factor = min(speed_factor, speed_factor * (float)min_xy_segment_time / (float)MAX_FREQ_TIME);
-#endif
+#endif // XY_FREQUENCY_LIMIT

  // Correct the speed  
  if( speed_factor < 1.0)
--- a/Marlin/stepper.cpp
+++ b/Marlin/stepper.cpp
@ -55,7 +55,7 @@ volatile static unsigned long step_events_completed; // The number of step event
 #ifdef ADVANCE
  static long advance_rate, advance, final_advance = 0;
  static long old_advance = 0;
-  static long e_steps[3];
+  static long e_steps[4];
 #endif
 static long acceleration_time, deceleration_time;
 //static unsigned long accelerate_until, decelerate_after, acceleration_rate, initial_rate, final_rate, nominal_rate;
@ -200,6 +200,8 @@ void checkHitEndstops()
     setTargetHotend0(0);
     setTargetHotend1(0);
     setTargetHotend2(0);
+     setTargetHotend3(0);
+     setTargetBed(0);
   }
 #endif
 }
@ -553,7 +555,7 @@ ISR(TIMER1_COMPA_vect)
      #endif //ADVANCE

      counter_x += current_block->steps_x;
-        #ifdef CONFIG_STEPPERS_TOSHIBA
+#ifdef CONFIG_STEPPERS_TOSHIBA
 	/* The toshiba stepper controller require much longer pulses
 	 * tjerfore we 'stage' decompose the pulses between high, and
 	 * low instead of doing each in turn. The extra tests add enough
@ -681,7 +683,7 @@ ISR(TIMER1_COMPA_vect)
          WRITE_E_STEP(INVERT_E_STEP_PIN);
        }
      #endif //!ADVANCE
-      #endif
+#endif // CONFIG_STEPPERS_TOSHIBA
      step_events_completed += 1;
      if(step_events_completed >= current_block->step_event_count) break;
    }
@ -807,6 +809,22 @@ ISR(TIMER1_COMPA_vect)
        }
      }
 #endif
+ #if EXTRUDERS > 3
+      if (e_steps[3] != 0) {
+        WRITE(E3_STEP_PIN, INVERT_E_STEP_PIN);
+        if (e_steps[3] < 0) {
+          WRITE(E3_DIR_PIN, INVERT_E3_DIR);
+          e_steps[3]++;
+          WRITE(E3_STEP_PIN, !INVERT_E_STEP_PIN);
+        }
+        else if (e_steps[3] > 0) {
+          WRITE(E3_DIR_PIN, !INVERT_E3_DIR);
+          e_steps[3]--;
+          WRITE(E3_STEP_PIN, !INVERT_E_STEP_PIN);
+        }
+      }
+ #endif
+
    }
  }
 #endif // ADVANCE
@ -846,6 +864,9 @@ void st_init()
  #if defined(E2_DIR_PIN) && (E2_DIR_PIN > -1)
    SET_OUTPUT(E2_DIR_PIN);
  #endif
+  #if defined(E3_DIR_PIN) && (E3_DIR_PIN > -1)
+    SET_OUTPUT(E3_DIR_PIN);
+  #endif

  //Initialize Enable Pins - steppers default to disabled.

@ -887,6 +908,10 @@ void st_init()
    SET_OUTPUT(E2_ENABLE_PIN);
    if(!E_ENABLE_ON) WRITE(E2_ENABLE_PIN,HIGH);
  #endif
+  #if defined(E3_ENABLE_PIN) && (E3_ENABLE_PIN > -1)
+    SET_OUTPUT(E3_ENABLE_PIN);
+    if(!E_ENABLE_ON) WRITE(E3_ENABLE_PIN,HIGH);
+  #endif

  //endstops and pullups

@ -977,6 +1002,11 @@ void st_init()
    WRITE(E2_STEP_PIN,INVERT_E_STEP_PIN);
    disable_e2();
  #endif
+  #if defined(E3_STEP_PIN) && (E3_STEP_PIN > -1)
+    SET_OUTPUT(E3_STEP_PIN);
+    WRITE(E3_STEP_PIN,INVERT_E_STEP_PIN);
+    disable_e3();
+  #endif

  // waveform generation = 0100 = CTC
  TCCR1B &= ~(1<<WGM13);
@ -1007,6 +1037,7 @@ void st_init()
    e_steps[0] = 0;
    e_steps[1] = 0;
    e_steps[2] = 0;
+    e_steps[3] = 0;
    TIMSK0 |= (1<<OCIE0A);
  #endif //ADVANCE

@ -1068,6 +1099,7 @@ void finishAndDisableSteppers()
  disable_e0();
  disable_e1();
  disable_e2();
+  disable_e3();
 }

 void quickStop()
--- a/Marlin/stepper.h
+++ b/Marlin/stepper.h
@ -23,7 +23,11 @@

 #include "planner.h"

-#if EXTRUDERS > 2
+#if EXTRUDERS > 3
+  #define WRITE_E_STEP(v) { if(current_block->active_extruder == 3) { WRITE(E3_STEP_PIN, v); } else { if(current_block->active_extruder == 2) { WRITE(E2_STEP_PIN, v); } else { if(current_block->active_extruder == 1) { WRITE(E1_STEP_PIN, v); } else { WRITE(E0_STEP_PIN, v); }}}}
+  #define NORM_E_DIR() { if(current_block->active_extruder == 3) { WRITE(E3_DIR_PIN, !INVERT_E3_DIR); } else { if(current_block->active_extruder == 2) { WRITE(E2_DIR_PIN, !INVERT_E2_DIR); } else { if(current_block->active_extruder == 1) { WRITE(E1_DIR_PIN, !INVERT_E1_DIR); } else { WRITE(E0_DIR_PIN, !INVERT_E0_DIR); }}}}
+  #define REV_E_DIR() { if(current_block->active_extruder == 3) { WRITE(E3_DIR_PIN, INVERT_E3_DIR); } else { if(current_block->active_extruder == 2) { WRITE(E2_DIR_PIN, INVERT_E2_DIR); } else { if(current_block->active_extruder == 1) { WRITE(E1_DIR_PIN, INVERT_E1_DIR); } else { WRITE(E0_DIR_PIN, INVERT_E0_DIR); }}}}
+#elif EXTRUDERS > 2
  #define WRITE_E_STEP(v) { if(current_block->active_extruder == 2) { WRITE(E2_STEP_PIN, v); } else { if(current_block->active_extruder == 1) { WRITE(E1_STEP_PIN, v); } else { WRITE(E0_STEP_PIN, v); }}}
  #define NORM_E_DIR() { if(current_block->active_extruder == 2) { WRITE(E2_DIR_PIN, !INVERT_E2_DIR); } else { if(current_block->active_extruder == 1) { WRITE(E1_DIR_PIN, !INVERT_E1_DIR); } else { WRITE(E0_DIR_PIN, !INVERT_E0_DIR); }}}
  #define REV_E_DIR() { if(current_block->active_extruder == 2) { WRITE(E2_DIR_PIN, INVERT_E2_DIR); } else { if(current_block->active_extruder == 1) { WRITE(E1_DIR_PIN, INVERT_E1_DIR); } else { WRITE(E0_DIR_PIN, INVERT_E0_DIR); }}}
--- a/Marlin/temperature.cpp
+++ b/Marlin/temperature.cpp
@ -115,14 +115,16 @@ static volatile bool temp_meas_ready = false;
  static unsigned long extruder_autofan_last_check;
 #endif  

-#if EXTRUDERS > 3
+#if EXTRUDERS > 4
  # error Unsupported number of extruders
+#elif EXTRUDERS > 3
+  # define ARRAY_BY_EXTRUDERS(v1, v2, v3, v4) { v1, v2, v3, v4 }
 #elif EXTRUDERS > 2
-  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1, v2, v3 }
+  # define ARRAY_BY_EXTRUDERS(v1, v2, v3, v4) { v1, v2, v3 }
 #elif EXTRUDERS > 1
-  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1, v2 }
+  # define ARRAY_BY_EXTRUDERS(v1, v2, v3, v4) { v1, v2 }
 #else
-  # define ARRAY_BY_EXTRUDERS(v1, v2, v3) { v1 }
+  # define ARRAY_BY_EXTRUDERS(v1, v2, v3, v4) { v1 }
 #endif

 #ifdef PIDTEMP
@ -144,10 +146,10 @@ static volatile bool temp_meas_ready = false;
 #endif //PIDTEMP

 // Init min and max temp with extreme values to prevent false errors during startup
-static int minttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_LO_TEMP , HEATER_1_RAW_LO_TEMP , HEATER_2_RAW_LO_TEMP );
-static int maxttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_HI_TEMP , HEATER_1_RAW_HI_TEMP , HEATER_2_RAW_HI_TEMP );
-static int minttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 0, 0, 0 );
-static int maxttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 16383, 16383, 16383 );
+static int minttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_LO_TEMP , HEATER_1_RAW_LO_TEMP , HEATER_2_RAW_LO_TEMP, HEATER_3_RAW_LO_TEMP);
+static int maxttemp_raw[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_RAW_HI_TEMP , HEATER_1_RAW_HI_TEMP , HEATER_2_RAW_HI_TEMP, HEATER_3_RAW_HI_TEMP);
+static int minttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 0, 0, 0, 0 );
+static int maxttemp[EXTRUDERS] = ARRAY_BY_EXTRUDERS( 16383, 16383, 16383, 16383 );
 //static int bed_minttemp_raw = HEATER_BED_RAW_LO_TEMP; /* No bed mintemp error implemented?!? */
 #ifdef BED_MAXTEMP
 static int bed_maxttemp_raw = HEATER_BED_RAW_HI_TEMP;
@ -157,8 +159,8 @@ static int bed_maxttemp_raw = HEATER_BED_RAW_HI_TEMP;
  static void *heater_ttbl_map[2] = {(void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE };
  static uint8_t heater_ttbllen_map[2] = { HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN };
 #else
-  static void *heater_ttbl_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( (void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE, (void *)HEATER_2_TEMPTABLE );
-  static uint8_t heater_ttbllen_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN, HEATER_2_TEMPTABLE_LEN );
+  static void *heater_ttbl_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( (void *)HEATER_0_TEMPTABLE, (void *)HEATER_1_TEMPTABLE, (void *)HEATER_2_TEMPTABLE, (void *)HEATER_3_TEMPTABLE );
+  static uint8_t heater_ttbllen_map[EXTRUDERS] = ARRAY_BY_EXTRUDERS( HEATER_0_TEMPTABLE_LEN, HEATER_1_TEMPTABLE_LEN, HEATER_2_TEMPTABLE_LEN, HEATER_3_TEMPTABLE_LEN );
 #endif

 static float analog2temp(int raw, uint8_t e);
@ -166,8 +168,8 @@ static float analog2tempBed(int raw);
 static void updateTemperaturesFromRawValues();

 #ifdef WATCH_TEMP_PERIOD
-int watch_start_temp[EXTRUDERS] = ARRAY_BY_EXTRUDERS(0,0,0);
-unsigned long watchmillis[EXTRUDERS] = ARRAY_BY_EXTRUDERS(0,0,0);
+int watch_start_temp[EXTRUDERS] = ARRAY_BY_EXTRUDERS(0,0,0,0);
+unsigned long watchmillis[EXTRUDERS] = ARRAY_BY_EXTRUDERS(0,0,0,0);
 #endif //WATCH_TEMP_PERIOD

 #ifndef SOFT_PWM_SCALE
@ -200,7 +202,8 @@ void PID_autotune(float temp, int extruder, int ncycles)

 #if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1) || \
    (defined(EXTRUDER_1_AUTO_FAN_PIN) && EXTRUDER_1_AUTO_FAN_PIN > -1) || \
-    (defined(EXTRUDER_2_AUTO_FAN_PIN) && EXTRUDER_2_AUTO_FAN_PIN > -1)
+    (defined(EXTRUDER_2_AUTO_FAN_PIN) && EXTRUDER_2_AUTO_FAN_PIN > -1) || \
+    (defined(EXTRUDER_3_AUTO_FAN_PIN) && EXTRUDER_3_AUTO_FAN_PIN > -1)
  unsigned long extruder_autofan_last_check = millis();
 #endif

@ -243,7 +246,8 @@ void PID_autotune(float temp, int extruder, int ncycles)

      #if (defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1) || \
          (defined(EXTRUDER_1_AUTO_FAN_PIN) && EXTRUDER_1_AUTO_FAN_PIN > -1) || \
-          (defined(EXTRUDER_2_AUTO_FAN_PIN) && EXTRUDER_2_AUTO_FAN_PIN > -1)
+          (defined(EXTRUDER_2_AUTO_FAN_PIN) && EXTRUDER_2_AUTO_FAN_PIN > -1) || \
+          (defined(EXTRUDER_3_AUTO_FAN_PIN) && EXTRUDER_3_AUTO_FAN_PIN > -1)
      if(millis() - extruder_autofan_last_check > 2500) {
        checkExtruderAutoFans();
        extruder_autofan_last_check = millis();
@ -420,6 +424,19 @@ void checkExtruderAutoFans()
        fanState |= 4;
    }
  #endif
+  #if defined(EXTRUDER_3_AUTO_FAN_PIN) && EXTRUDER_3_AUTO_FAN_PIN > -1
+    if (current_temperature[3] > EXTRUDER_AUTO_FAN_TEMPERATURE) 
+    {
+      if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_0_AUTO_FAN_PIN) 
+        fanState |= 1;
+      else if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_1_AUTO_FAN_PIN) 
+        fanState |= 2;
+      else if (EXTRUDER_3_AUTO_FAN_PIN == EXTRUDER_2_AUTO_FAN_PIN) 
+        fanState |= 4;
+      else
+        fanState |= 8;
+    }
+  #endif
  
  // update extruder auto fan states
  #if defined(EXTRUDER_0_AUTO_FAN_PIN) && EXTRUDER_0_AUTO_FAN_PIN > -1
@ -434,6 +451,12 @@ void checkExtruderAutoFans()
        && EXTRUDER_2_AUTO_FAN_PIN != EXTRUDER_1_AUTO_FAN_PIN)
      setExtruderAutoFanState(EXTRUDER_2_AUTO_FAN_PIN, (fanState & 4) != 0);
  #endif
+  #if defined(EXTRUDER_3_AUTO_FAN_PIN) && EXTRUDER_3_AUTO_FAN_PIN > -1
+    if (EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN 
+        && EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_1_AUTO_FAN_PIN)
+        && EXTRUDER_3_AUTO_FAN_PIN != EXTRUDER_0_AUTO_FAN_PIN)
+      setExtruderAutoFanState(EXTRUDER_3_AUTO_FAN_PIN, (fanState & 8) != 0);
+  #endif
 }

 #endif // any extruder auto fan pins set
@ -837,6 +860,9 @@ void tp_init()
  #if defined(HEATER_2_PIN) && (HEATER_2_PIN > -1) 
    SET_OUTPUT(HEATER_2_PIN);
  #endif
+  #if defined(HEATER_3_PIN) && (HEATER_3_PIN > -1) 
+    SET_OUTPUT(HEATER_3_PIN);
+  #endif
  #if defined(HEATER_BED_PIN) && (HEATER_BED_PIN > -1) 
    SET_OUTPUT(HEATER_BED_PIN);
  #endif  
@ -897,6 +923,13 @@ void tp_init()
      DIDR2 |= 1<<(TEMP_2_PIN - 8); 
    #endif
  #endif
+  #if defined(TEMP_3_PIN) && (TEMP_3_PIN > -1)
+    #if TEMP_3_PIN < 8
+      DIDR0 |= 1 << TEMP_3_PIN; 
+    #else
+      DIDR2 |= 1<<(TEMP_3_PIN - 8); 
+    #endif
+  #endif
  #if defined(TEMP_BED_PIN) && (TEMP_BED_PIN > -1)
    #if TEMP_BED_PIN < 8
       DIDR0 |= 1<<TEMP_BED_PIN; 
@ -987,6 +1020,28 @@ void tp_init()
  }
 #endif //MAXTEMP 2

+#if (EXTRUDERS > 3) && defined(HEATER_3_MINTEMP)
+  minttemp[3] = HEATER_3_MINTEMP;
+  while(analog2temp(minttemp_raw[3], 3) < HEATER_3_MINTEMP) {
+#if HEATER_3_RAW_LO_TEMP < HEATER_3_RAW_HI_TEMP
+    minttemp_raw[3] += OVERSAMPLENR;
+#else
+    minttemp_raw[3] -= OVERSAMPLENR;
+#endif
+  }
+#endif //MINTEMP 3
+#if (EXTRUDERS > 3) && defined(HEATER_3_MAXTEMP)
+  maxttemp[3] = HEATER_3_MAXTEMP;
+  while(analog2temp(maxttemp_raw[3], 3) > HEATER_3_MAXTEMP) {
+#if HEATER_3_RAW_LO_TEMP < HEATER_3_RAW_HI_TEMP
+    maxttemp_raw[3] -= OVERSAMPLENR;
+#else
+    maxttemp_raw[3] += OVERSAMPLENR;
+#endif
+  }
+#endif // MAXTEMP 3
+
+
 #ifdef BED_MINTEMP
  /* No bed MINTEMP error implemented?!? */ /*
  while(analog2tempBed(bed_minttemp_raw) < BED_MINTEMP) {
@ -1075,6 +1130,7 @@ void thermal_runaway_protection(int *state, unsigned long *timer, float temperat
          disable_e0();
          disable_e1();
          disable_e2();
+          disable_e3();
          manage_heater();
          lcd_update();
        }
@ -1113,6 +1169,15 @@ void disable_heater()
    #endif
  #endif

+  #if defined(TEMP_3_PIN) && TEMP_3_PIN > -1 && EXTRUDERS > 3
+    target_temperature[3]=0;
+    soft_pwm[3]=0;
+    #if defined(HEATER_3_PIN) && HEATER_3_PIN > -1  
+      WRITE(HEATER_3_PIN,LOW);
+    #endif
+  #endif 
+
+
  #if defined(TEMP_BED_PIN) && TEMP_BED_PIN > -1
    target_temperature_bed=0;
    soft_pwm_bed=0;
@ -1227,8 +1292,9 @@ ISR(TIMER0_COMPB_vect)
  static unsigned long raw_temp_0_value = 0;
  static unsigned long raw_temp_1_value = 0;
  static unsigned long raw_temp_2_value = 0;
+  static unsigned long raw_temp_3_value = 0;
  static unsigned long raw_temp_bed_value = 0;
-  static unsigned char temp_state = 10;
+  static unsigned char temp_state = 12;
  static unsigned char pwm_count = (1 << SOFT_PWM_SCALE);
  static unsigned char soft_pwm_0;
 #ifdef SLOW_PWM_HEATERS
@ -1236,6 +1302,7 @@ ISR(TIMER0_COMPB_vect)
  static unsigned char state_heater_0 = 0;
  static unsigned char state_timer_heater_0 = 0;
 #endif 
+
 #if (EXTRUDERS > 1) || defined(HEATERS_PARALLEL)
  static unsigned char soft_pwm_1;
 #ifdef SLOW_PWM_HEATERS
@ -1250,6 +1317,14 @@ ISR(TIMER0_COMPB_vect)
  static unsigned char state_timer_heater_2 = 0;
 #endif 
 #endif
+#if EXTRUDERS > 3
+  static unsigned char soft_pwm_3;
+#ifdef SLOW_PWM_HEATERS
+  static unsigned char state_heater_3 = 0;
+  static unsigned char state_timer_heater_3 = 0;
+#endif
+#endif
+
 #if HEATER_BED_PIN > -1
  static unsigned char soft_pwm_b;
 #ifdef SLOW_PWM_HEATERS
@ -1283,6 +1358,12 @@ ISR(TIMER0_COMPB_vect)
    soft_pwm_2 = soft_pwm[2];
    if(soft_pwm_2 > 0) WRITE(HEATER_2_PIN,1); else WRITE(HEATER_2_PIN,0);
 #endif
+#if EXTRUDERS > 3
+    soft_pwm_3 = soft_pwm[3];
+    if(soft_pwm_3 > 0) WRITE(HEATER_3_PIN,1); else WRITE(HEATER_3_PIN,0);
+#endif
+
+
 #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
    soft_pwm_b = soft_pwm_bed;
    if(soft_pwm_b > 0) WRITE(HEATER_BED_PIN,1); else WRITE(HEATER_BED_PIN,0);
@ -1298,12 +1379,17 @@ ISR(TIMER0_COMPB_vect)
    WRITE(HEATER_1_PIN,0);
 #endif
  }
+
 #if EXTRUDERS > 1
  if(soft_pwm_1 < pwm_count) WRITE(HEATER_1_PIN,0);
 #endif
 #if EXTRUDERS > 2
  if(soft_pwm_2 < pwm_count) WRITE(HEATER_2_PIN,0);
 #endif
+#if EXTRUDERS > 3
+  if(soft_pwm_3 < pwm_count) WRITE(HEATER_3_PIN,0);
+#endif
+
 #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
  if(soft_pwm_b < pwm_count) WRITE(HEATER_BED_PIN,0);
 #endif
@ -1406,6 +1492,32 @@ ISR(TIMER0_COMPB_vect)
    }
 #endif

+#if EXTRUDERS > 3
+    // EXTRUDER 3
+    soft_pwm_3 = soft_pwm[3];
+    if (soft_pwm_3 > 0) {
+      // turn ON heather only if the minimum time is up 
+      if (state_timer_heater_3 == 0) { 
+	// if change state set timer 
+	if (state_heater_3 == 0) {
+	  state_timer_heater_3 = MIN_STATE_TIME;
+	}
+	state_heater_3 = 1;
+	WRITE(HEATER_3_PIN, 1);
+      }
+    } else {
+      // turn OFF heather only if the minimum time is up 
+      if (state_timer_heater_3 == 0) {
+	// if change state set timer 
+	if (state_heater_3 == 1) {
+	  state_timer_heater_3 = MIN_STATE_TIME;
+	}
+	state_heater_3 = 0;
+	WRITE(HEATER_3_PIN, 0);
+      }
+    }
+#endif
+
 #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
    // BED
    soft_pwm_b = soft_pwm_bed;
@ -1479,6 +1591,21 @@ ISR(TIMER0_COMPB_vect)
  }
 #endif

+#if EXTRUDERS > 3
+  // EXTRUDER 3
+  if (soft_pwm_3 < slow_pwm_count) {
+    // turn OFF heather only if the minimum time is up 
+    if (state_timer_heater_3 == 0) { 
+      // if change state set timer 
+      if (state_heater_3 == 1) {
+	state_timer_heater_3 = MIN_STATE_TIME;
+      }
+      state_heater_3 = 0;
+      WRITE(HEATER_3_PIN, 0);
+    }
+  }
+#endif
+  
 #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
  // BED
  if (soft_pwm_b < slow_pwm_count) {
@ -1527,6 +1654,12 @@ ISR(TIMER0_COMPB_vect)
      state_timer_heater_2--;
 #endif

+#if EXTRUDERS > 3
+    // Extruder 3
+    if (state_timer_heater_3 > 0) 
+      state_timer_heater_3--;
+#endif
+    
 #if defined(HEATER_BED_PIN) && HEATER_BED_PIN > -1
    // Bed   
    if (state_timer_heater_b > 0) 
@ -1614,10 +1747,28 @@ ISR(TIMER0_COMPB_vect)
      #if defined(TEMP_2_PIN) && (TEMP_2_PIN > -1)
        raw_temp_2_value += ADC;
      #endif
-      temp_state = 8;//change so that Filament Width is also measured
-      
+      temp_state = 8;
+      break;
+    case 8: // Prepare TEMP_3
+      #if defined(TEMP_3_PIN) && (TEMP_3_PIN > -1)
+        #if TEMP_3_PIN > 7
+          ADCSRB = 1<<MUX5;
+        #else
+          ADCSRB = 0;
+        #endif
+        ADMUX = ((1 << REFS0) | (TEMP_3_PIN & 0x07));
+        ADCSRA |= 1<<ADSC; // Start conversion
+      #endif
+      lcd_buttons_update();
+      temp_state = 9;
+      break;
+    case 9: // Measure TEMP_3
+      #if defined(TEMP_3_PIN) && (TEMP_3_PIN > -1)
+        raw_temp_3_value += ADC;
+      #endif
+      temp_state = 10; //change so that Filament Width is also measured
      break;
-    case 8: //Prepare FILWIDTH 
+    case 10: //Prepare FILWIDTH 
     #if defined(FILWIDTH_PIN) && (FILWIDTH_PIN> -1) 
      #if FILWIDTH_PIN>7 
         ADCSRB = 1<<MUX5;
@ -1628,9 +1779,9 @@ ISR(TIMER0_COMPB_vect)
      ADCSRA |= 1<<ADSC; // Start conversion 
     #endif 
     lcd_buttons_update();       
-     temp_state = 9; 
+     temp_state = 11; 
     break; 
-    case 9:   //Measure FILWIDTH 
+    case 11:   //Measure FILWIDTH 
     #if defined(FILWIDTH_PIN) &&(FILWIDTH_PIN > -1) 
     //raw_filwidth_value += ADC;  //remove to use an IIR filter approach 
      if(ADC>102)  //check that ADC is reading a voltage > 0.5 volts, otherwise don't take in the data.
@ -1646,7 +1797,7 @@ ISR(TIMER0_COMPB_vect)
     break;      
      
      
-    case 10: //Startup, delay initial temp reading a tiny bit so the hardware can settle.
+    case 12: //Startup, delay initial temp reading a tiny bit so the hardware can settle.
      temp_state = 0;
      break;
 //    default:
@ -1668,6 +1819,9 @@ ISR(TIMER0_COMPB_vect)
 #endif
 #if EXTRUDERS > 2
      current_temperature_raw[2] = raw_temp_2_value;
+#endif
+#if EXTRUDERS > 3
+      current_temperature_raw[3] = raw_temp_3_value;
 #endif
      current_temperature_bed_raw = raw_temp_bed_value;
    }
@ -1683,6 +1837,7 @@ ISR(TIMER0_COMPB_vect)
    raw_temp_0_value = 0;
    raw_temp_1_value = 0;
    raw_temp_2_value = 0;
+    raw_temp_3_value = 0;
    raw_temp_bed_value = 0;

 #if HEATER_0_RAW_LO_TEMP > HEATER_0_RAW_HI_TEMP
@ -1699,6 +1854,8 @@ ISR(TIMER0_COMPB_vect)
 #endif
        min_temp_error(0);
    }
+
+
 #if EXTRUDERS > 1
 #if HEATER_1_RAW_LO_TEMP > HEATER_1_RAW_HI_TEMP
    if(current_temperature_raw[1] <= maxttemp_raw[1]) {
@ -1731,6 +1888,23 @@ ISR(TIMER0_COMPB_vect)
        min_temp_error(2);
    }
 #endif
+#if EXTRUDERS > 3
+#if HEATER_3_RAW_LO_TEMP > HEATER_3_RAW_HI_TEMP
+    if(current_temperature_raw[3] <= maxttemp_raw[3]) {
+#else
+    if(current_temperature_raw[3] >= maxttemp_raw[3]) {
+#endif
+        max_temp_error(3);
+    }
+#if HEATER_3_RAW_LO_TEMP > HEATER_3_RAW_HI_TEMP
+    if(current_temperature_raw[3] >= minttemp_raw[3]) {
+#else
+    if(current_temperature_raw[3] <= minttemp_raw[3]) {
+#endif
+        min_temp_error(3);
+    }
+#endif
+

  /* No bed MINTEMP error? */
 #if defined(BED_MAXTEMP) && (TEMP_SENSOR_BED != 0)
@ -1790,5 +1964,3 @@ float unscalePID_d(float d)
 }

 #endif //PIDTEMP
-
-
--- a/Marlin/temperature.h
+++ b/Marlin/temperature.h
@ -159,6 +159,15 @@ FORCE_INLINE bool isCoolingBed() {
 #define setTargetHotend2(_celsius) do{}while(0)
 #endif
 #if EXTRUDERS > 3
+#define degHotend3() degHotend(3)
+#define degTargetHotend3() degTargetHotend(3)
+#define setTargetHotend3(_celsius) setTargetHotend((_celsius), 3)
+#define isHeatingHotend3() isHeatingHotend(3)
+#define isCoolingHotend3() isCoolingHotend(3)
+#else
+#define setTargetHotend3(_celsius) do{}while(0)
+#endif
+#if EXTRUDERS > 4
 #error Invalid number of extruders
 #endif

@ -171,24 +180,24 @@ void updatePID();

 #if defined (THERMAL_RUNAWAY_PROTECTION_PERIOD) && THERMAL_RUNAWAY_PROTECTION_PERIOD > 0
 void thermal_runaway_protection(int *state, unsigned long *timer, float temperature, float target_temperature, int heater_id, int period_seconds, int hysteresis_degc);
-static int thermal_runaway_state_machine[3]; // = {0,0,0};
-static unsigned long thermal_runaway_timer[3]; // = {0,0,0};
+static int thermal_runaway_state_machine[4]; // = {0,0,0,0};
+static unsigned long thermal_runaway_timer[4]; // = {0,0,0,0};
 static bool thermal_runaway = false;
-  #if TEMP_SENSOR_BED != 0
+#if TEMP_SENSOR_BED != 0
  static int thermal_runaway_bed_state_machine;
  static unsigned long thermal_runaway_bed_timer;
-  #endif
+#endif
 #endif

 FORCE_INLINE void autotempShutdown(){
- #ifdef AUTOTEMP
+#ifdef AUTOTEMP
  if(autotemp_enabled)
  {
    autotemp_enabled=false;
    if(degTargetHotend(active_extruder)>autotemp_min)
      setTargetHotend(0,active_extruder);
  }
- #endif
+#endif
 }

 void PID_autotune(float temp, int extruder, int ncycles);
@ -197,4 +206,3 @@ void setExtruderAutoFanState(int pin, bool state);
 void checkExtruderAutoFans();

 #endif
-
--- a/Marlin/thermistortables.h
+++ b/Marlin/thermistortables.h
@ -5,7 +5,7 @@

 #define OVERSAMPLENR 16

-#if (THERMISTORHEATER_0 == 1) || (THERMISTORHEATER_1 == 1)  || (THERMISTORHEATER_2 == 1) || (THERMISTORBED == 1) //100k bed thermistor
+#if (THERMISTORHEATER_0 == 1) || (THERMISTORHEATER_1 == 1)  || (THERMISTORHEATER_2 == 1) || (THERMISTORHEATER_3 == 1) || (THERMISTORBED == 1) //100k bed thermistor

 const short temptable_1[][2] PROGMEM = {
 {       23*OVERSAMPLENR ,       300     },
@ -71,7 +71,7 @@ const short temptable_1[][2] PROGMEM = {
 {       1008*OVERSAMPLENR       ,       0       } //safety
 };
 #endif
-#if (THERMISTORHEATER_0 == 2) || (THERMISTORHEATER_1 == 2) || (THERMISTORHEATER_2 == 2) || (THERMISTORBED == 2) //200k bed thermistor
+#if (THERMISTORHEATER_0 == 2) || (THERMISTORHEATER_1 == 2) || (THERMISTORHEATER_2 == 2) || (THERMISTORHEATER_3 == 2) || (THERMISTORBED == 2) //200k bed thermistor
 const short temptable_2[][2] PROGMEM = {
 //200k ATC Semitec 204GT-2
 //Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
@ -111,7 +111,7 @@ const short temptable_2[][2] PROGMEM = {
 };

 #endif
-#if (THERMISTORHEATER_0 == 3) || (THERMISTORHEATER_1 == 3) || (THERMISTORHEATER_2 == 3) || (THERMISTORBED == 3) //mendel-parts
+#if (THERMISTORHEATER_0 == 3) || (THERMISTORHEATER_1 == 3) || (THERMISTORHEATER_2 == 3) || (THERMISTORHEATER_3 == 3) || (THERMISTORBED == 3) //mendel-parts
 const short temptable_3[][2] PROGMEM = {
                {1*OVERSAMPLENR,864},
                {21*OVERSAMPLENR,300},
@ -144,7 +144,7 @@ const short temptable_3[][2] PROGMEM = {
        };

 #endif
-#if (THERMISTORHEATER_0 == 4) || (THERMISTORHEATER_1 == 4) || (THERMISTORHEATER_2 == 4) || (THERMISTORBED == 4) //10k thermistor
+#if (THERMISTORHEATER_0 == 4) || (THERMISTORHEATER_1 == 4) || (THERMISTORHEATER_2 == 4) || (THERMISTORHEATER_3 == 4) || (THERMISTORBED == 4) //10k thermistor
 const short temptable_4[][2] PROGMEM = {
   {1*OVERSAMPLENR, 430},
   {54*OVERSAMPLENR, 137},
@ -169,7 +169,7 @@ const short temptable_4[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 5) || (THERMISTORHEATER_1 == 5) || (THERMISTORHEATER_2 == 5) || (THERMISTORBED == 5) //100k ParCan thermistor (104GT-2)
+#if (THERMISTORHEATER_0 == 5) || (THERMISTORHEATER_1 == 5) || (THERMISTORHEATER_2 == 5) || (THERMISTORHEATER_3 == 5) || (THERMISTORBED == 5) //100k ParCan thermistor (104GT-2)
 const short temptable_5[][2] PROGMEM = {
 // ATC Semitec 104GT-2 (Used in ParCan)
 // Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
@ -209,7 +209,7 @@ const short temptable_5[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 6) || (THERMISTORHEATER_1 == 6) || (THERMISTORHEATER_2 == 6) || (THERMISTORBED == 6) // 100k Epcos thermistor
+#if (THERMISTORHEATER_0 == 6) || (THERMISTORHEATER_1 == 6) || (THERMISTORHEATER_2 == 6) || (THERMISTORHEATER_3 == 6) || (THERMISTORBED == 6) // 100k Epcos thermistor
 const short temptable_6[][2] PROGMEM = {
   {1*OVERSAMPLENR, 350},
   {28*OVERSAMPLENR, 250}, //top rating 250C
@ -252,7 +252,7 @@ const short temptable_6[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 7) || (THERMISTORHEATER_1 == 7) || (THERMISTORHEATER_2 == 7) || (THERMISTORBED == 7) // 100k Honeywell 135-104LAG-J01
+#if (THERMISTORHEATER_0 == 7) || (THERMISTORHEATER_1 == 7) || (THERMISTORHEATER_2 == 7) || (THERMISTORHEATER_3 == 7) || (THERMISTORBED == 7) // 100k Honeywell 135-104LAG-J01
 const short temptable_7[][2] PROGMEM = {
   {1*OVERSAMPLENR, 941},
   {19*OVERSAMPLENR, 362},
@ -315,7 +315,7 @@ const short temptable_7[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 71) || (THERMISTORHEATER_1 == 71) || (THERMISTORHEATER_2 == 71) || (THERMISTORBED == 71) // 100k Honeywell 135-104LAF-J01
+#if (THERMISTORHEATER_0 == 71) || (THERMISTORHEATER_1 == 71) || (THERMISTORHEATER_2 == 71) || (THERMISTORHEATER_3 == 71) || (THERMISTORBED == 71) // 100k Honeywell 135-104LAF-J01
 // R0 = 100000 Ohm
 // T0 = 25 °C
 // Beta = 3974
@ -466,7 +466,7 @@ const short temptable_71[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 8) || (THERMISTORHEATER_1 == 8) || (THERMISTORHEATER_2 == 8) || (THERMISTORBED == 8)
+#if (THERMISTORHEATER_0 == 8) || (THERMISTORHEATER_1 == 8) || (THERMISTORHEATER_2 == 8) || (THERMISTORHEATER_3 == 8) || (THERMISTORBED == 8)
 // 100k 0603 SMD Vishay NTCS0603E3104FXT (4.7k pullup)
 const short temptable_8[][2] PROGMEM = {
   {1*OVERSAMPLENR, 704},
@ -491,7 +491,7 @@ const short temptable_8[][2] PROGMEM = {
   {1008*OVERSAMPLENR, 0}
 };
 #endif
-#if (THERMISTORHEATER_0 == 9) || (THERMISTORHEATER_1 == 9) || (THERMISTORHEATER_2 == 9) || (THERMISTORBED == 9)
+#if (THERMISTORHEATER_0 == 9) || (THERMISTORHEATER_1 == 9) || (THERMISTORHEATER_2 == 9) || (THERMISTORHEATER_3 == 9) || (THERMISTORBED == 9)
 // 100k GE Sensing AL03006-58.2K-97-G1 (4.7k pullup)
 const short temptable_9[][2] PROGMEM = {
 	{1*OVERSAMPLENR, 936},
@ -527,7 +527,7 @@ const short temptable_9[][2] PROGMEM = {
 	{1016*OVERSAMPLENR, 0}
 };
 #endif
-#if (THERMISTORHEATER_0 == 10) || (THERMISTORHEATER_1 == 10) || (THERMISTORHEATER_2 == 10) || (THERMISTORBED == 10)
+#if (THERMISTORHEATER_0 == 10) || (THERMISTORHEATER_1 == 10) || (THERMISTORHEATER_2 == 10) || (THERMISTORHEATER_3 == 10) || (THERMISTORBED == 10)
 // 100k RS thermistor 198-961 (4.7k pullup)
 const short temptable_10[][2] PROGMEM = {
   {1*OVERSAMPLENR, 929},
@ -564,7 +564,7 @@ const short temptable_10[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 11) || (THERMISTORHEATER_1 == 11) || (THERMISTORHEATER_2 == 11) || (THERMISTORBED == 11) 
+#if (THERMISTORHEATER_0 == 11) || (THERMISTORHEATER_1 == 11) || (THERMISTORHEATER_2 == 11) || (THERMISTORHEATER_3 == 11) || (THERMISTORBED == 11) 
 // QU-BD silicone bed QWG-104F-3950 thermistor

 const short temptable_11[][2] PROGMEM = {
@ -621,7 +621,7 @@ const short temptable_11[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 13) || (THERMISTORHEATER_1 == 13) || (THERMISTORHEATER_2 == 13) || (THERMISTORBED == 13)
+#if (THERMISTORHEATER_0 == 13) || (THERMISTORHEATER_1 == 13) || (THERMISTORHEATER_2 == 13) || (THERMISTORHEATER_3 == 13) || (THERMISTORBED == 13)
 // Hisens thermistor B25/50 =3950 +/-1%

 const short temptable_13[][2] PROGMEM = {
@ -705,6 +705,10 @@ This does not match the normal thermistor behaviour so we need to set the follow
 # define HEATER_2_RAW_HI_TEMP 16383
 # define HEATER_2_RAW_LO_TEMP 0
 #endif
+#if (THERMISTORHEATER_3 == 20)
+# define HEATER_3_RAW_HI_TEMP 16383
+# define HEATER_3_RAW_LO_TEMP 0
+#endif
 #if (THERMISTORBED == 20)
 # define HEATER_BED_RAW_HI_TEMP 16383
 # define HEATER_BED_RAW_LO_TEMP 0
@ -762,7 +766,7 @@ const short temptable_20[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 51) || (THERMISTORHEATER_1 == 51) || (THERMISTORHEATER_2 == 51) || (THERMISTORBED == 51)
+#if (THERMISTORHEATER_0 == 51) || (THERMISTORHEATER_1 == 51) || (THERMISTORHEATER_2 == 51) || (THERMISTORHEATER_3 == 51) || (THERMISTORBED == 51)
 // 100k EPCOS (WITH 1kohm RESISTOR FOR PULLUP, R9 ON SANGUINOLOLU! NOT FOR 4.7kohm PULLUP! THIS IS NOT NORMAL!)
 // Verified by linagee.
 // Calculated using 1kohm pullup, voltage divider math, and manufacturer provided temp/resistance
@ -824,7 +828,7 @@ const short temptable_51[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 52) || (THERMISTORHEATER_1 == 52) || (THERMISTORHEATER_2 == 52) || (THERMISTORBED == 52) 
+#if (THERMISTORHEATER_0 == 52) || (THERMISTORHEATER_1 == 52) || (THERMISTORHEATER_2 == 52) || (THERMISTORHEATER_3 == 52) || (THERMISTORBED == 52) 
 // 200k ATC Semitec 204GT-2 (WITH 1kohm RESISTOR FOR PULLUP, R9 ON SANGUINOLOLU! NOT FOR 4.7kohm PULLUP! THIS IS NOT NORMAL!)
 // Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
 // Calculated using 1kohm pullup, voltage divider math, and manufacturer provided temp/resistance
@ -865,7 +869,7 @@ const short temptable_52[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 55) || (THERMISTORHEATER_1 == 55) || (THERMISTORHEATER_2 == 55) || (THERMISTORBED == 55) 
+#if (THERMISTORHEATER_0 == 55) || (THERMISTORHEATER_1 == 55) || (THERMISTORHEATER_2 == 55) || (THERMISTORHEATER_3 == 55) || (THERMISTORBED == 55) 
 // 100k ATC Semitec 104GT-2 (Used on ParCan) (WITH 1kohm RESISTOR FOR PULLUP, R9 ON SANGUINOLOLU! NOT FOR 4.7kohm PULLUP! THIS IS NOT NORMAL!)
 // Verified by linagee. Source: http://shop.arcol.hu/static/datasheets/thermistors.pdf
 // Calculated using 1kohm pullup, voltage divider math, and manufacturer provided temp/resistance
@ -906,7 +910,7 @@ const short temptable_55[][2] PROGMEM = {
 };
 #endif

-#if (THERMISTORHEATER_0 == 60) || (THERMISTORHEATER_1 == 60) || (THERMISTORHEATER_2 == 60) || (THERMISTORBED == 60) // Maker's Tool Works Kapton Bed Thermister
+#if (THERMISTORHEATER_0 == 60) || (THERMISTORHEATER_1 == 60) || (THERMISTORHEATER_2 == 60) || (THERMISTORHEATER_3 == 60) || (THERMISTORBED == 60) // Maker's Tool Works Kapton Bed Thermister
 // ./createTemperatureLookup.py --r0=100000 --t0=25 --r1=0 --r2=4700 --beta=3950 
 // r0: 100000
 // t0: 25
@ -1037,7 +1041,7 @@ const short temptable_12[][2] PROGMEM = {
 #define PtAdVal(T,R0,Rup) (short)(1024/(Rup/PtRt(T,R0)+1))
 #define PtLine(T,R0,Rup) { PtAdVal(T,R0,Rup)*OVERSAMPLENR, T },

-#if (THERMISTORHEATER_0 == 110) || (THERMISTORHEATER_1 == 110) || (THERMISTORHEATER_2 == 110) || (THERMISTORBED == 110) // Pt100 with 1k0 pullup
+#if (THERMISTORHEATER_0 == 110) || (THERMISTORHEATER_1 == 110) || (THERMISTORHEATER_2 == 110) || (THERMISTORHEATER_3 == 110) || (THERMISTORBED == 110) // Pt100 with 1k0 pullup
 const short temptable_110[][2] PROGMEM = {
 // only few values are needed as the curve is very flat  
  PtLine(0,100,1000)
@ -1049,7 +1053,7 @@ const short temptable_110[][2] PROGMEM = {
  PtLine(300,100,1000)
 };
 #endif
-#if (THERMISTORHEATER_0 == 147) || (THERMISTORHEATER_1 == 147) || (THERMISTORHEATER_2 == 147) || (THERMISTORBED == 147) // Pt100 with 4k7 pullup
+#if (THERMISTORHEATER_0 == 147) || (THERMISTORHEATER_1 == 147) || (THERMISTORHEATER_2 == 147) || (THERMISTORHEATER_3 == 147) || (THERMISTORBED == 147) // Pt100 with 4k7 pullup
 const short temptable_147[][2] PROGMEM = {
 // only few values are needed as the curve is very flat  
  PtLine(0,100,4700)
@ -1061,7 +1065,7 @@ const short temptable_147[][2] PROGMEM = {
  PtLine(300,100,4700)
 };
 #endif
-#if (THERMISTORHEATER_0 == 1010) || (THERMISTORHEATER_1 == 1010) || (THERMISTORHEATER_2 == 1010) || (THERMISTORBED == 1010) // Pt1000 with 1k0 pullup
+#if (THERMISTORHEATER_0 == 1010) || (THERMISTORHEATER_1 == 1010) || (THERMISTORHEATER_2 == 1010) || (THERMISTORHEATER_3 == 1010) || (THERMISTORBED == 1010) // Pt1000 with 1k0 pullup
 const short temptable_1010[][2] PROGMEM = {
  PtLine(0,1000,1000)
  PtLine(25,1000,1000)
@ -1078,7 +1082,7 @@ const short temptable_1010[][2] PROGMEM = {
  PtLine(300,1000,1000)
 };
 #endif
-#if (THERMISTORHEATER_0 == 1047) || (THERMISTORHEATER_1 == 1047) || (THERMISTORHEATER_2 == 1047) || (THERMISTORBED == 1047) // Pt1000 with 4k7 pullup
+#if (THERMISTORHEATER_0 == 1047) || (THERMISTORHEATER_1 == 1047) || (THERMISTORHEATER_2 == 1047) || (THERMISTORHEATER_3 == 1047) || (THERMISTORBED == 1047) // Pt1000 with 4k7 pullup
 const short temptable_1047[][2] PROGMEM = {
 // only few values are needed as the curve is very flat  
  PtLine(0,1000,4700)
@ -1163,6 +1167,29 @@ const short temptable_1047[][2] PROGMEM = {
 # endif
 #endif

+#ifdef THERMISTORHEATER_3
+# define HEATER_3_TEMPTABLE TT_NAME(THERMISTORHEATER_3)
+# define HEATER_3_TEMPTABLE_LEN (sizeof(HEATER_3_TEMPTABLE)/sizeof(*HEATER_3_TEMPTABLE))
+#else
+# ifdef HEATER_3_USES_THERMISTOR
+#  error No heater 3 thermistor table specified
+# else  // HEATER_3_USES_THERMISTOR
+#  define HEATER_3_TEMPTABLE NULL
+#  define HEATER_3_TEMPTABLE_LEN 0
+# endif // HEATER_3_USES_THERMISTOR
+#endif
+
+//Set the high and low raw values for the heater, this indicates which raw value is a high or low temperature
+#ifndef HEATER_3_RAW_HI_TEMP
+# ifdef HEATER_3_USES_THERMISTOR   //In case of a thermistor the highest temperature results in the lowest ADC value
+#  define HEATER_3_RAW_HI_TEMP 0
+#  define HEATER_3_RAW_LO_TEMP 16383
+# else                          //In case of an thermocouple the highest temperature results in the highest ADC value
+#  define HEATER_3_RAW_HI_TEMP 16383
+#  define HEATER_3_RAW_LO_TEMP 0
+# endif
+#endif
+
 #ifdef THERMISTORBED
 # define BEDTEMPTABLE TT_NAME(THERMISTORBED)
 # define BEDTEMPTABLE_LEN (sizeof(BEDTEMPTABLE)/sizeof(*BEDTEMPTABLE))
--- a/Marlin/ultralcd.cpp
+++ b/Marlin/ultralcd.cpp
@ -431,6 +431,11 @@ static void lcd_tune_menu()
 #if TEMP_SENSOR_2 != 0
    MENU_ITEM_EDIT(int3, MSG_NOZZLE2, &target_temperature[2], 0, HEATER_2_MAXTEMP - 15);
 #endif
+#if TEMP_SENSOR_3 != 0
+    MENU_ITEM_EDIT(int3, MSG_NOZZLE3, &target_temperature[3], 0, HEATER_3_MAXTEMP - 15);
+#endif
+
+
 #if TEMP_SENSOR_BED != 0
    MENU_ITEM_EDIT(int3, MSG_BED, &target_temperature_bed, 0, BED_MAXTEMP - 15);
 #endif
@ -443,6 +448,10 @@ static void lcd_tune_menu()
 #if TEMP_SENSOR_2 != 0
    MENU_ITEM_EDIT(int3, MSG_FLOW2, &extruder_multiply[2], 10, 999);
 #endif
+#if TEMP_SENSOR_3 != 0
+    MENU_ITEM_EDIT(int3, MSG_FLOW3, &extruder_multiply[3], 10, 999);
+#endif
+

 #ifdef BABYSTEPPING
    #ifdef BABYSTEP_XY
@ -515,23 +524,46 @@ void lcd_preheat_abs2()
 }
 #endif //3 extruder preheat

-#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 //more than one extruder present
-void lcd_preheat_pla012()
+#if TEMP_SENSOR_3 != 0 //4 extruder preheat
+void lcd_preheat_pla3()
+{
+    setTargetHotend3(plaPreheatHotendTemp);
+    setTargetBed(plaPreheatHPBTemp);
+    fanSpeed = plaPreheatFanSpeed;
+    lcd_return_to_status();
+    setWatch(); // heater sanity check timer
+}
+
+void lcd_preheat_abs3()
+{
+    setTargetHotend3(absPreheatHotendTemp);
+    setTargetBed(absPreheatHPBTemp);
+    fanSpeed = absPreheatFanSpeed;
+    lcd_return_to_status();
+    setWatch(); // heater sanity check timer
+}
+
+#endif //4 extruder preheat
+
+#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 || TEMP_SENSOR_3 != 0 //more than one extruder present
+void lcd_preheat_pla0123()
 {
    setTargetHotend0(plaPreheatHotendTemp);
    setTargetHotend1(plaPreheatHotendTemp);
    setTargetHotend2(plaPreheatHotendTemp);
+    setTargetHotend3(plaPreheatHotendTemp);
    setTargetBed(plaPreheatHPBTemp);
    fanSpeed = plaPreheatFanSpeed;
    lcd_return_to_status();
    setWatch(); // heater sanity check timer
 }

-void lcd_preheat_abs012()
+void lcd_preheat_abs0123()
 {
    setTargetHotend0(absPreheatHotendTemp);
    setTargetHotend1(absPreheatHotendTemp);
    setTargetHotend2(absPreheatHotendTemp);
+    setTargetHotend3(absPreheatHotendTemp);
    setTargetBed(absPreheatHPBTemp);
    fanSpeed = absPreheatFanSpeed;
    lcd_return_to_status();
@ -566,9 +598,12 @@ static void lcd_preheat_pla_menu()
 #if TEMP_SENSOR_2 != 0 //3 extruder preheat
  MENU_ITEM(function, MSG_PREHEAT_PLA2, lcd_preheat_pla2);
 #endif //3 extruder preheat
-#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 //all extruder preheat
-    MENU_ITEM(function, MSG_PREHEAT_PLA012, lcd_preheat_pla012);
-#endif //2 extruder preheat
+#if TEMP_SENSOR_3 != 0 //4 extruder preheat
+  MENU_ITEM(function, MSG_PREHEAT_PLA3, lcd_preheat_pla3);
+#endif //4 extruder preheat
+#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 || TEMP_SENSOR_3 != 0 //all extruder preheat
+  MENU_ITEM(function, MSG_PREHEAT_PLA0123, lcd_preheat_pla0123);
+#endif //all extruder preheat
 #if TEMP_SENSOR_BED != 0
  MENU_ITEM(function, MSG_PREHEAT_PLA_BEDONLY, lcd_preheat_pla_bedonly);
 #endif
@ -586,9 +621,13 @@ static void lcd_preheat_abs_menu()
 #if TEMP_SENSOR_2 != 0 //3 extruder preheat
  MENU_ITEM(function, MSG_PREHEAT_ABS2, lcd_preheat_abs2);
 #endif //3 extruder preheat
-#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 //all extruder preheat
-    MENU_ITEM(function, MSG_PREHEAT_ABS012, lcd_preheat_abs012);
-#endif //2 extruder preheat
+#if TEMP_SENSOR_3 != 0 //4 extruder preheat
+  MENU_ITEM(function, MSG_PREHEAT_ABS3, lcd_preheat_abs3);
+#endif //4 extruder preheat
+#if TEMP_SENSOR_1 != 0 || TEMP_SENSOR_2 != 0 || TEMP_SENSOR_3 != 0 //all extruder preheat
+  MENU_ITEM(function, MSG_PREHEAT_ABS0123, lcd_preheat_abs0123);
+#endif //all extruder preheat
+
 #if TEMP_SENSOR_BED != 0
 MENU_ITEM(function, MSG_PREHEAT_ABS_BEDONLY, lcd_preheat_abs_bedonly);
 #endif
@ -600,6 +639,7 @@ void lcd_cooldown()
    setTargetHotend0(0);
    setTargetHotend1(0);
    setTargetHotend2(0);
+    setTargetHotend3(0);
    setTargetBed(0);
    fanSpeed = 0;
    lcd_return_to_status();
@ -777,6 +817,9 @@ static void lcd_control_temperature_menu()
 #if TEMP_SENSOR_2 != 0
  MENU_ITEM_EDIT(int3, MSG_NOZZLE2, &target_temperature[2], 0, HEATER_2_MAXTEMP - 15);
 #endif
+#if TEMP_SENSOR_3 != 0
+  MENU_ITEM_EDIT(int3, MSG_NOZZLE3, &target_temperature[3], 0, HEATER_3_MAXTEMP - 15);
+#endif
 #if TEMP_SENSOR_BED != 0
  MENU_ITEM_EDIT(int3, MSG_BED, &target_temperature_bed, 0, BED_MAXTEMP - 15);
 #endif
@ -916,13 +959,15 @@ static void lcd_control_volumetric_menu()
 		MENU_ITEM_EDIT_CALLBACK(float43, MSG_FILAMENT_SIZE_EXTRUDER_1, &filament_size[1], DEFAULT_NOMINAL_FILAMENT_DIA - .5, DEFAULT_NOMINAL_FILAMENT_DIA + .5, calculate_volumetric_multipliers);
 #if EXTRUDERS > 2
 		MENU_ITEM_EDIT_CALLBACK(float43, MSG_FILAMENT_SIZE_EXTRUDER_2, &filament_size[2], DEFAULT_NOMINAL_FILAMENT_DIA - .5, DEFAULT_NOMINAL_FILAMENT_DIA + .5, calculate_volumetric_multipliers);
-#endif
-#endif
+#if EXTRUDERS > 3
+		MENU_ITEM_EDIT_CALLBACK(float43, MSG_FILAMENT_SIZE_EXTRUDER_3, &filament_size[3], DEFAULT_NOMINAL_FILAMENT_DIA - .5, DEFAULT_NOMINAL_FILAMENT_DIA + .5, calculate_volumetric_multipliers);
+#endif //EXTRUDERS > 3
+#endif //EXTRUDERS > 2
+#endif //EXTRUDERS > 1
 	}

 	END_MENU();
 }
-
 #ifdef DOGLCD
 static void lcd_set_contrast()
 {
@ -962,7 +1007,6 @@ static void lcd_control_retract_menu()
    MENU_ITEM_EDIT(float3, MSG_CONTROL_RETRACT_RECOVERF, &retract_recover_feedrate, 1, 999);
    END_MENU();
 }
-
 #endif //FWRETRACT

 #if SDCARDDETECT == -1
--- a/Marlin/ultralcd.h
+++ b/Marlin/ultralcd.h
@ -46,9 +46,9 @@
  
  extern bool cancel_heatup;
  
-  #ifdef FILAMENT_LCD_DISPLAY
+#ifdef FILAMENT_LCD_DISPLAY
  extern unsigned long message_millis;
-  #endif
+#endif

  void lcd_buzz(long duration,uint16_t freq);
  bool lcd_clicked();