prevent too long extrudes, or too cold extrudes

Marlin/Configuration.h

@@ -20,9 +20,6 @@
 // if unwanted behavior is observed on a user's machine when running at very slow speeds.
 #define MINIMUM_PLANNER_SPEED 2.0 // (mm/sec)
 
-// If defined the movements slow down when the look ahead buffer is only half full
-#define SLOWDOWN
-
 // BASIC SETTINGS: select your board type, thermistor type, axis scaling, and endstop configuration
 
 //// The following define selects which electronics board you have. Please choose the one that matches your setup
@@ -248,7 +245,12 @@ const bool Z_ENDSTOPS_INVERTING = true; // set to true to invert the logic of th
 #define DEFAULT_XYJERK                20.0    // (mm/sec)
 #define DEFAULT_ZJERK                 0.4     // (mm/sec)
 
+// If defined the movements slow down when the look ahead buffer is only half full
+#define SLOWDOWN
 
+//default stepper release if idle
+#define DEFAULT_STEPPER_DEACTIVE_TIME 60
+#define DEFAULT_STEPPER_DEACTIVE_COMMAND "M84 X Y E"  //z stays  powered
 
 
 //===========================================================================
@@ -338,6 +340,11 @@ const bool Z_ENDSTOPS_INVERTING = true; // set to true to invert the logic of th
   #define AUTOTEMP_OLDWEIGHT 0.98
 #endif
 
+//this prevents dangerous Extruder moves, i.e. if the temperature is under the limit
+//can be software-disabled for whatever purposes by
+#define PREVENT_DANGEROUS_EXTRUDE
+#define EXTRUDE_MINTEMP 190
+#define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.
 
 const int dropsegments=5; //everything with less than this number of steps will be ignored as move and joined with the next movement
 

Marlin/Marlin.pde

@@ -110,6 +110,7 @@
 // M206 - set additional homeing offset
 // M220 - set speed factor override percentage S:factor in percent
 // M301 - Set PID parameters P I and D
+// M302 - Allow cold extrudes
 // M400 - Finish all moves
 // M500 - stores paramters in EEPROM
 // M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).  
@@ -176,7 +177,8 @@ const int sensitive_pins[] = SENSITIVE_PINS; // Sensitive pin list for M42
 //Inactivity shutdown variables
 static unsigned long previous_millis_cmd = 0;
 static unsigned long max_inactive_time = 0;
-static unsigned long stepper_inactive_time = 0;
+static unsigned long stepper_inactive_time = DEFAULT_STEPPER_DEACTIVE_TIME*1000;
+static unsigned long last_stepperdisabled_time=30*1000; //first release check after 30 seconds
 
 static unsigned long starttime=0;
 static unsigned long stoptime=0;
@@ -1057,6 +1059,12 @@ FORCE_INLINE void process_commands()
       }
       break;
     #endif //PIDTEMP
+      
+    case 302: // finish all moves
+    {
+      allow_cold_extrudes(true);
+    }
+    break;
     case 400: // finish all moves
     {
       st_synchronize();
@@ -1188,13 +1196,16 @@ void manage_inactivity(byte debug)
   if( (millis()-previous_millis_cmd) >  max_inactive_time ) 
     if(max_inactive_time) 
       kill(); 
-  if( (millis()-previous_millis_cmd) >  stepper_inactive_time ) 
   if(stepper_inactive_time)  
+  if( (millis()-last_stepperdisabled_time) >  stepper_inactive_time ) 
   {
-      disable_x(); 
+    if(previous_millis_cmd>last_stepperdisabled_time)
-      disable_y(); 
+      last_stepperdisabled_time=previous_millis_cmd;
-      disable_z(); 
+    else
-      disable_e(); 
+    {
+      enquecommand(DEFAULT_STEPPER_DEACTIVE_COMMAND); 
+      last_stepperdisabled_time=millis();
+    }
   }
   #ifdef EXTRUDER_RUNOUT_PREVENT
     if( (millis()-previous_millis_cmd) >  EXTRUDER_RUNOUT_SECONDS*1000 ) 

Marlin/planner.cpp

@@ -106,7 +106,9 @@ volatile unsigned char block_buffer_tail;           // Index of the block to pro
 //===========================================================================
 //=============================private variables ============================
 //===========================================================================
-
+#ifdef PREVENT_DANGEROUS_EXTRUDE
+  bool allow_cold_extrude=false;
+#endif
 #ifdef XY_FREQUENCY_LIMIT
   // Used for the frequency limit
   static unsigned char old_direction_bits = 0;               // Old direction bits. Used for speed calculations
@@ -467,6 +469,22 @@ void plan_buffer_line(const float &x, const float &y, const float &z, const floa
   target[Z_AXIS] = lround(z*axis_steps_per_unit[Z_AXIS]);     
   target[E_AXIS] = lround(e*axis_steps_per_unit[E_AXIS]);
   
+  #ifdef PREVENT_DANGEROUS_EXTRUDE
+    if(target[E_AXIS]!=position[E_AXIS])
+    if(degHotend(active_extruder)<EXTRUDE_MINTEMP && !allow_cold_extrude)
+    {
+      position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
+      SERIAL_ECHO_START;
+      SERIAL_ECHOLNPGM(" cold extrusion prevented");
+    }
+    if(labs(target[E_AXIS]-position[E_AXIS])>axis_steps_per_unit[E_AXIS]*EXTRUDE_MAXLENGTH)
+    {
+      position[E_AXIS]=target[E_AXIS]; //behave as if the move really took place, but ignore E part
+      SERIAL_ECHO_START;
+      SERIAL_ECHOLNPGM(" too long extrusion prevented");
+    }
+  #endif
+  
   // Prepare to set up new block
   block_t *block = &block_buffer[block_buffer_head];
   
@@ -786,3 +804,9 @@ uint8_t movesplanned()
  return (block_buffer_head-block_buffer_tail + BLOCK_BUFFER_SIZE) & (BLOCK_BUFFER_SIZE - 1);
 }
 
+void allow_cold_extrudes(bool allow)
+{
+  #ifdef PREVENT_DANGEROUS_EXTRUDE
+    allow_cold_extrude=allow;
+  #endif
+}

Marlin/planner.h

@@ -140,4 +140,6 @@ FORCE_INLINE bool blocks_queued()
   else
     return true;
 }
+
+void allow_cold_extrudes(bool allow);
 #endif