optimised some math-code

Marlin/Marlin_main.cpp

     //SERIAL_ECHOPGM("f_delta x="); SERIAL_ECHO(f_scara[X_AXIS]);
     //SERIAL_ECHOPGM(" y="); SERIAL_ECHO(f_scara[Y_AXIS]);
   
-    x_sin = sin(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1/1000;
-    x_cos = cos(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1/1000;
-    y_sin = sin(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2/1000;
-    y_cos = cos(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2/1000;
+    x_sin = sin(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1;
+    x_cos = cos(f_scara[X_AXIS]/SCARA_RAD2DEG) * Linkage_1;
+    y_sin = sin(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2;
+    y_cos = cos(f_scara[Y_AXIS]/SCARA_RAD2DEG) * Linkage_2;
    
   //  SERIAL_ECHOPGM(" x_sin="); SERIAL_ECHO(x_sin);
   //  SERIAL_ECHOPGM(" x_cos="); SERIAL_ECHO(x_cos);
   // The maths and first version has been done by QHARLEY . Integrated into masterbranch 06/2014 and slightly restructured by Joachim Cerny in June 2014
   
   float SCARA_pos[2];
-  static float L1_2, L2_2, SCARA_C2, SCARA_S2, SCARA_K1, SCARA_K2, SCARA_theta, SCARA_psi; 
+  static float SCARA_C2, SCARA_S2, SCARA_K1, SCARA_K2, SCARA_theta, SCARA_psi; 
   
   SCARA_pos[X_AXIS] = cartesian[X_AXIS] * axis_scaling[X_AXIS] - SCARA_offset_x;  //Translate SCARA to standard X Y
   SCARA_pos[Y_AXIS] = cartesian[Y_AXIS] * axis_scaling[Y_AXIS] - SCARA_offset_y;  // With scaling factor.
   
-  L1_2 = pow(Linkage_1/1000,2);
-  L2_2 = pow(Linkage_2/1000,2);
-  
   #if (Linkage_1 == Linkage_2)
-    SCARA_C2 = ( ( pow(SCARA_pos[X_AXIS],2) + pow(SCARA_pos[Y_AXIS],2) ) / (2 * L1_2) ) - 1;
+    SCARA_C2 = ( ( sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS]) ) / (2 * (float)L1_2) ) - 1;
   #else
-    SCARA_C2 =   ( pow(SCARA_pos[X_AXIS],2) + pow(SCARA_pos[Y_AXIS],2) - L1_2 - L2_2 ) / 45000; 
+    SCARA_C2 =   ( sq(SCARA_pos[X_AXIS]) + sq(SCARA_pos[Y_AXIS]) - (float)L1_2 - (float)L2_2 ) / 45000; 
   #endif
   
-  SCARA_S2 = sqrt( 1 - pow(SCARA_C2,2) );
+  SCARA_S2 = sqrt( 1 - sq(SCARA_C2) );
   
-  SCARA_K1 = Linkage_1/1000+Linkage_2/1000*SCARA_C2;
-  SCARA_K2 = Linkage_2/1000*SCARA_S2;
+  SCARA_K1 = Linkage_1 + Linkage_2 * SCARA_C2;
+  SCARA_K2 = Linkage_2 * SCARA_S2;
   
-  SCARA_theta = (atan2(SCARA_pos[X_AXIS],SCARA_pos[Y_AXIS])-atan2(SCARA_K1, SCARA_K2))*-1;
-  SCARA_psi = atan2(SCARA_S2,SCARA_C2);
+  SCARA_theta = ( atan2(SCARA_pos[X_AXIS],SCARA_pos[Y_AXIS])-atan2(SCARA_K1, SCARA_K2) ) * -1;
+  SCARA_psi   =   atan2(SCARA_S2,SCARA_C2);
   
   delta[X_AXIS] = SCARA_theta * SCARA_RAD2DEG;  // Multiply by 180/Pi  -  theta is support arm angle
   delta[Y_AXIS] = (SCARA_theta + SCARA_psi) * SCARA_RAD2DEG;  //       -  equal to sub arm angle (inverted motor)
   delta[Z_AXIS] = cartesian[Z_AXIS];
   
-  
   /*
   SERIAL_ECHOPGM("cartesian x="); SERIAL_ECHO(cartesian[X_AXIS]);
   SERIAL_ECHOPGM(" y="); SERIAL_ECHO(cartesian[Y_AXIS]);
   SERIAL_ECHOPGM(" S2="); SERIAL_ECHO(SCARA_S2);
   SERIAL_ECHOPGM(" Theta="); SERIAL_ECHO(SCARA_theta);
   SERIAL_ECHOPGM(" Psi="); SERIAL_ECHOLN(SCARA_psi);
-  SERIAL_ECHOLN(" ");
-  */
+  SERIAL_ECHOLN(" ");*/
 }
 
 #endif

Marlin/example_configurations/SCARA/Configuration.h

 // You might need Z-Min endstop on SCARA-Printer to use this feature. Actually untested!
 // Uncomment to use Morgan scara mode
 #define SCARA  
-#define scara_segments_per_second 200
+#define scara_segments_per_second 200 //careful, two much will decrease performance...
 // Length of inner support arm
-#define Linkage_1 150000 //um      Preprocessor cannot handle decimal point...
-// Length of outer support arm     Measure arm lengths precisely, and enter 
-#define Linkage_2 150000 //um      define in micrometer
+#define Linkage_1 150 //mm      Preprocessor cannot handle decimal point...
+// Length of outer support arm     Measure arm lengths precisely and enter 
+#define Linkage_2 150 //mm    
 
 // SCARA tower offset (position of Tower relative to bed zero position) 
 // This needs to be reasonably accurate as it defines the printbed position in the SCARA space.
 #define SCARA_offset_y -56 //mm
 #define SCARA_RAD2DEG 57.2957795  // to convert RAD to degrees
 
+#define THETA_HOMING_OFFSET 0	//calculatated from Calibration Guide and command M360 / M114 see picture in http://reprap.harleystudio.co.za/?page_id=1073
+#define PSI_HOMING_OFFSET 0  // calculatated from Calibration Guide and command M364 / M114 see picture in http://reprap.harleystudio.co.za/?page_id=1073
+
+//some helper variables to make kinematics faster
+#define L1_2 sq(Linkage_1) // do not change
+#define L2_2 sq(Linkage_2) // do not change
+
 //===========================================================================
 //========================= SCARA Settings end ==================================
 //===========================================================================
 #define MAX_REDUNDANT_TEMP_SENSOR_DIFF 10
 
 // Actual temperature must be close to target for this long before M109 returns success
-#define TEMP_RESIDENCY_TIME 10  // (seconds)
-#define TEMP_HYSTERESIS 3       // (degC) range of +/- temperatures considered "close" to the target one
+#define TEMP_RESIDENCY_TIME 3  // (seconds)
+#define TEMP_HYSTERESIS 2       // (degC) range of +/- temperatures considered "close" to the target one
 #define TEMP_WINDOW     1       // (degC) Window around target to start the residency timer x degC early.
 
 // The minimal temperature defines the temperature below which the heater will not be enabled It is used
 //#define HEATER_BED_DUTY_CYCLE_DIVIDER 4
 
 // If you want the M105 heater power reported in watts, define the BED_WATTS, and (shared for all extruders) EXTRUDER_WATTS
-//#define EXTRUDER_WATTS (12.0*12.0/6.7) //  P=I^2/R
-//#define BED_WATTS (12.0*12.0/1.1)      // P=I^2/R
+#define EXTRUDER_WATTS (2*2/5.9) //  P=I^2/R
+#define BED_WATTS (5.45*5.45/2.2)      // P=I^2/R
 
 // PID settings:
 // Comment the following line to disable PID and enable bang-bang.
 #ifdef PIDTEMP
   //#define PID_DEBUG // Sends debug data to the serial port.
   //#define PID_OPENLOOP 1 // Puts PID in open loop. M104/M140 sets the output power from 0 to PID_MAX
-  #define PID_FUNCTIONAL_RANGE 10 // If the temperature difference between the target temperature and the actual temperature
+  #define PID_FUNCTIONAL_RANGE 20 // If the temperature difference between the target temperature and the actual temperature
                                   // is more then PID_FUNCTIONAL_RANGE then the PID will be shut off and the heater will be set to min/max.
   #define PID_INTEGRAL_DRIVE_MAX 255  //limit for the integral term
   #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
 // Ultimaker
-    #define  DEFAULT_Kp 22.2
-    #define  DEFAULT_Ki 1.08
-    #define  DEFAULT_Kd 114
+  //  #define  DEFAULT_Kp 22.2
+  //  #define  DEFAULT_Ki 1.08
+   // #define  DEFAULT_Kd 114
+  
+ // Jhead MK5: From Autotune  
+  //  #define  DEFAULT_Kp 20.92
+   // #define  DEFAULT_Ki 1.51
+  //  #define  DEFAULT_Kd 72.34
+    
+ //Merlin Hotend: From Autotune  
+    #define  DEFAULT_Kp 24.5
+    #define  DEFAULT_Ki 1.72
+    #define  DEFAULT_Kd 87.73
 
 // MakerGear
 //    #define  DEFAULT_Kp 7.0
 //    #define  DEFAULT_Kd 12
 
 // Mendel Parts V9 on 12V
-//    #define  DEFAULT_Kp 63.0
-//    #define  DEFAULT_Ki 2.25
-//    #define  DEFAULT_Kd 440
+  //  #define  DEFAULT_Kp 63.0
+   // #define  DEFAULT_Ki 2.25
+   // #define  DEFAULT_Kd 440
 #endif // PIDTEMP
 
 // Bed Temperature Control
 // If your configuration is significantly different than this and you don't understand the issues involved, you probably
 // 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 PIDTEMPBED
 //
-//#define BED_LIMIT_SWITCHING
+#define BED_LIMIT_SWITCHING
 
 // This sets the max power delivered 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)
 #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, aggressive factor of .15 (vs .1, 1, 10)
-    #define  DEFAULT_bedKp 10.00
-    #define  DEFAULT_bedKi .023
-    #define  DEFAULT_bedKd 305.4
+  //  #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_bedKi 1.41
 //    #define  DEFAULT_bedKd 1675.16
 
+//12v Heatbed Mk3 12V in parallel
+//from pidautotune
+    #define  DEFAULT_bedKp 630.14
+    #define  DEFAULT_bedKi 121.71
+    #define  DEFAULT_bedKd 815.64
+    
 // 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
+//#define PREVENT_DANGEROUS_EXTRUDE
 //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 150
 #define EXTRUDE_MAXLENGTH (X_MAX_LENGTH+Y_MAX_LENGTH) //prevent extrusion of very large distances.
 
 //===========================================================================
 #define INVERT_X_DIR false    // for Mendel set to false, for Orca set to true
 #define INVERT_Y_DIR false    // for Mendel set to true, for Orca set to false
 #define INVERT_Z_DIR true     // for Mendel set to false, for Orca set to true
-#define INVERT_E0_DIR true   // for direct drive extruder v9 set to true, for geared extruder set to false
+#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
 
 //Manual homing switch locations:
 // For deltabots this means top and center of the Cartesian print volume.
 // For SCARA: Offset between HomingPosition and Bed X=0 / Y=0
-#define MANUAL_X_HOME_POS -20
-#define MANUAL_Y_HOME_POS -48
+#define MANUAL_X_HOME_POS -22.
+#define MANUAL_Y_HOME_POS -52.
 #define MANUAL_Z_HOME_POS 0.1  // Distance between nozzle and print surface after homing.
 
 
 
 // default settings
 
-//#define DEFAULT_AXIS_STEPS_PER_UNIT   {85.6,85.6,200/1.25,970}  // default steps per unit for Ultimaker
-#define DEFAULT_AXIS_STEPS_PER_UNIT   {109,109,200/1.25,970}  // default steps per unit for Ultimaker
-#define DEFAULT_MAX_FEEDRATE          {200, 200, 30, 45}    // (mm/sec)
-#define DEFAULT_MAX_ACCELERATION      {300,300,30,1500}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.
+#define DEFAULT_AXIS_STEPS_PER_UNIT   {103.69,106.65,200/1.25,1000}  // default steps per unit for SCARA
+#define DEFAULT_MAX_FEEDRATE          {300, 300, 30, 25}    // (mm/sec)
+#define DEFAULT_MAX_ACCELERATION      {300,300,20,1000}    // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.
 
-#define DEFAULT_ACCELERATION          300    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
-#define DEFAULT_RETRACT_ACCELERATION  3000   // X, Y, Z and E max acceleration in mm/s^2 for retracts
+#define DEFAULT_ACCELERATION          400    // X, Y, Z and E max acceleration in mm/s^2 for printing moves
+#define DEFAULT_RETRACT_ACCELERATION  2000  // X, Y, Z and E max acceleration in mm/s^2 for retracts
 
 // Offset of the extruders (uncomment if using more than one and relying on firmware to position when changing).
-// The offset has to be X=0, Y=0 for the extruder 0 hotend (default extruder).
+// The offset has to be X=0, Y=0 for extruder 0 hotend (default extruder).
 // For the other hotends it is their distance from the extruder 0 hotend.
 // #define EXTRUDER_OFFSET_X {0.0, 20.00} // (in mm) for each extruder, offset of the hotend on the X axis
 // #define EXTRUDER_OFFSET_Y {0.0, 5.00}  // (in mm) for each extruder, offset of the hotend on the Y axis
 
 // The speed change that does not require acceleration (i.e. the software might assume it can be done instantaneously)
-#define DEFAULT_XYJERK                10.0    // (mm/sec)
-#define DEFAULT_ZJERK                 10.0     // (mm/sec)
-#define DEFAULT_EJERK                 5.0    // (mm/sec)
+#define DEFAULT_XYJERK                5    // (mm/sec)
+#define DEFAULT_ZJERK                 0.4    // (mm/sec)
+#define DEFAULT_EJERK                 3    // (mm/sec)
 
 //===========================================================================
 //=============================Additional Features===========================
 // M501 - reads parameters from EEPROM (if you need reset them after you changed them temporarily).
 // M502 - reverts to the default "factory settings".  You still need to store them in EEPROM afterwards if you want to.
 //define this to enable EEPROM support
-#define EEPROM_SETTINGS
+//#define EEPROM_SETTINGS
 //to disable EEPROM Serial responses and decrease program space by ~1700 byte: comment this out:
 // please keep turned on if you can.
 #define EEPROM_CHITCHAT