Merge pull request MarlinFirmware#244 from markfinn/pidbed

PID for heated bed

Marlin/Configuration.h

@@ -98,7 +98,7 @@
 #define PID_MAX 255 // limits current to nozzle; 255=full current
 #ifdef PIDTEMP
   //#define PID_DEBUG // Sends debug data to the serial port. 
-  //#define PID_OPENLOOP 1 // Puts PID in open loop. M104 sets the output power in %
+  //#define PID_OPENLOOP 1 // Puts PID in open loop. M104/M140 sets the output power from 0 to PID_MAX
   #define PID_INTEGRAL_DRIVE_MAX 255  //limit for the integral term
   #define K1 0.95 //smoothing factor withing the PID
   #define PID_dT ((16.0 * 8.0)/(F_CPU / 64.0 / 256.0)) //sampling period of the
@@ -120,6 +120,44 @@
 //    #define  DEFAULT_Kd 440
 #endif // PIDTEMP
 
+// Bed Temperature Control
+// Select PID or bang-bang with PIDTEMPBED.  If bang-bang, BED_LIMIT_SWITCHING will enable hysteresis
+//
+// uncomment this to enable PID on the bed.   It uses the same ferquency PWM as the extruder. 
+// If your PID_dT above is the default, and correct for your hardware/configuration, that means 7.689Hz,
+// which is fine for driving a square wave into a resistive load and does not significantly impact you FET heating.
+// This also works fine on a Fotek SSR-10DA Solid State Relay into a 250W heater. 
+// If your configuration is significantly different than this and you don't understand the issues involved, you proabaly 
+// shouldn't use bed PID until someone else verifies your hardware works.
+// If this is enabled, find your own PID constants below.
+//#define PIDTEMPBED
+//
+//#define BED_LIMIT_SWITCHING
+
+// This sets the max power delived to the bed, and replaces the HEATER_BED_DUTY_CYCLE_DIVIDER option.
+// all forms of bed control obey this (PID, bang-bang, bang-bang with hysteresis)
+// setting this to anything other than 255 enables a form of PWM to the bed just like HEATER_BED_DUTY_CYCLE_DIVIDER did,
+// so you shouldn't use it unless you are OK with PWM on your bed.  (see the comment on enabling PIDTEMPBED)
+#define MAX_BED_POWER 255 // limits duty cycle to bed; 255=full current
+
+#ifdef PIDTEMPBED
+//120v 250W silicone heater into 4mm borosilicate (MendelMax 1.5+)
+//from FOPDT model - kp=.39 Tp=405 Tdead=66, Tc set to 79.2, argressive factor of .15 (vs .1, 1, 10)
+    #define  DEFAULT_bedKp 10.00
+    #define  DEFAULT_bedKi .023
+    #define  DEFAULT_bedKd 305.4
+
+//120v 250W silicone heater into 4mm borosilicate (MendelMax 1.5+)
+//from pidautotune
+//    #define  DEFAULT_bedKp 97.1
+//    #define  DEFAULT_bedKi 1.41
+//    #define  DEFAULT_bedKd 1675.16
+
+// FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles.
+#endif // PIDTEMPBED
+
+
+
 //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

Marlin/Configuration_adv.h

@@ -5,13 +5,10 @@
 //=============================Thermal Settings  ============================
 //===========================================================================
 
-// Select one of these only to define how the bed temp is read.
-//
-//#define BED_LIMIT_SWITCHING
 #ifdef BED_LIMIT_SWITCHING
   #define BED_HYSTERESIS 2 //only disable heating if T>target+BED_HYSTERESIS and enable heating if T>target-BED_HYSTERESIS
 #endif
-#define BED_CHECK_INTERVAL 5000 //ms
+#define BED_CHECK_INTERVAL 5000 //ms between checks in bang-bang control
 
 //// Heating sanity check:
 // This waits for the watchperiod in milliseconds whenever an M104 or M109 increases the target temperature

Marlin/Marlin.pde

@@ -115,6 +115,7 @@
 // M301 - Set PID parameters P I and D
 // M302 - Allow cold extrudes
 // M303 - PID relay autotune S<temperature> sets the target temperature. (default target temperature = 150C)
+// M304 - Set bed PID parameters P I and D
 // M400 - Finish all moves
 // M500 - stores paramters in EEPROM
 // M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).  
@@ -986,10 +987,13 @@ void process_commands()
         SERIAL_ERROR_START;
         SERIAL_ERRORLNPGM(MSG_ERR_NO_THERMISTORS);
       #endif
-      #ifdef PIDTEMP
+
         SERIAL_PROTOCOLPGM(" @:");
         SERIAL_PROTOCOL(getHeaterPower(tmp_extruder));  
-      #endif
+
+        SERIAL_PROTOCOLPGM(" B@:");
+        SERIAL_PROTOCOL(getHeaterPower(-1));  
+
         SERIAL_PROTOCOLLN("");
       return;
       break;
@@ -1386,6 +1390,24 @@ void process_commands()
       }
       break;
     #endif //PIDTEMP
+    #ifdef PIDTEMPBED
+    case 304: // M304
+      {
+        if(code_seen('P')) bedKp = code_value();
+        if(code_seen('I')) bedKi = code_value()*PID_dT;
+        if(code_seen('D')) bedKd = code_value()/PID_dT;
+        updatePID();
+        SERIAL_PROTOCOL(MSG_OK);
+		SERIAL_PROTOCOL(" p:");
+        SERIAL_PROTOCOL(Kp);
+        SERIAL_PROTOCOL(" i:");
+        SERIAL_PROTOCOL(Ki/PID_dT);
+        SERIAL_PROTOCOL(" d:");
+        SERIAL_PROTOCOL(Kd*PID_dT);
+        SERIAL_PROTOCOLLN("");
+      }
+      break;
+    #endif //PIDTEMP
     case 240: // M240  Triggers a camera by emulating a Canon RC-1 : http://www.doc-diy.net/photo/rc-1_hacked/
      {
       #ifdef PHOTOGRAPH_PIN
@@ -1418,8 +1440,14 @@ void process_commands()
     case 303: // M303 PID autotune
     {
       float temp = 150.0;
+      int e=0;
+      int c=5;
+      if (code_seen('E')) e=code_value();
+			if (e<0)
+				temp=70;
       if (code_seen('S')) temp=code_value();
-      PID_autotune(temp);
+      if (code_seen('C')) c=code_value();
+      PID_autotune(temp, e, c);
     }
     break;
     case 400: // M400 finish all moves