added support for rack & pinion Z probe (Z_RACK_PINION)

Added support for compiling with Z_RACK_PINION for machines like Wilson2
which have a Z probe mounted to a pinion that is deployed by the
movement of the X axis.
Changed the auto bedleveling default limits to be based on the bed size
instead of absolute values (configuration.h).

Marlin/Conditionals_LCD.h

@@ -370,8 +370,8 @@
   /**
    * Set a flag for any enabled probe
    */
-  #define PROBE_SELECTED (ENABLED(FIX_MOUNTED_PROBE) || ENABLED(Z_PROBE_ALLEN_KEY) || HAS_Z_SERVO_ENDSTOP || ENABLED(Z_PROBE_SLED))
-
+  #define PROBE_SELECTED (ENABLED(FIX_MOUNTED_PROBE) || ENABLED(Z_PROBE_ALLEN_KEY) || HAS_Z_SERVO_ENDSTOP || ENABLED(Z_PROBE_SLED) || ENABLED(Z_RACK_PINION))
+  
   /**
    * Clear probe pin settings when no probe is selected
    */

Marlin/Configuration.h

@@ -562,6 +562,18 @@
 //#define Z_PROBE_SLED
 //#define SLED_DOCKING_OFFSET 5 // The extra distance the X axis must travel to pickup the sled. 0 should be fine but you can push it further if you'd like.
 
+// Enable if you have the Rack & Pinion style bed probe (i.e. Wilson II)
+//#define Z_RACK_PINION
+
+#ifdef Z_RACK_PINION
+#define Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
+#define Z_CLEARANCE_DEPLOY_PROBE 10
+#define X_PROBE_OFFSET_FROM_EXTRUDER 0     // Probe on: -left  +right
+#define Y_PROBE_OFFSET_FROM_EXTRUDER 45     // Probe on: -front +behind
+#define Z_PROBE_OFFSET_FROM_EXTRUDER -11  // -below (always!) 
+#define Z_SAFE_HOMING // home with probe in middle of bed not on the edge
+#endif
+
 // Z Probe to nozzle (X,Y) offset, relative to (0, 0).
 // X and Y offsets must be integers.
 //
@@ -725,6 +737,10 @@
 #define Y_MAX_POS 200
 #define Z_MAX_POS 200
 
+#ifdef Z_RACK_PINION
+#define X_MIN_POS 10
+#endif
+
 /**
  * Filament Runout Sensor
  * A mechanical or opto endstop is used to check for the presence of filament.
@@ -812,9 +828,9 @@
 
   // Set the boundaries for probing (where the probe can reach).
   #define LEFT_PROBE_BED_POSITION 15
-  #define RIGHT_PROBE_BED_POSITION 170
-  #define FRONT_PROBE_BED_POSITION 20
-  #define BACK_PROBE_BED_POSITION 170
+  #define RIGHT_PROBE_BED_POSITION (X_MAX_POS-30)
+  #define FRONT_PROBE_BED_POSITION (20+Y_PROBE_OFFSET_FROM_EXTRUDER)
+  #define BACK_PROBE_BED_POSITION (Y_MAX_POS-30)
 
   // The Z probe minimum outer margin (to validate G29 parameters).
   #define MIN_PROBE_EDGE 10
@@ -891,6 +907,7 @@
 #define HOMING_FEEDRATE_XY (50*60)
 #define HOMING_FEEDRATE_Z  (4*60)
 
+
 //=============================================================================
 //============================= Additional Features ===========================
 //=============================================================================

Marlin/Marlin_main.cpp

@@ -2050,6 +2050,10 @@ static void clean_up_after_endstop_or_probe_move() {
 
           deploy ? run_deploy_moves_script() : run_stow_moves_script();
 
+        #elif ENABLED(Z_RACK_PINION)
+
+          do_blocking_move_to_x(deploy? 0:X_MAX_POS);
+
         #endif
 
     #ifdef _TRIGGERED_WHEN_STOWED_TEST

Marlin/SanityCheck.h

@@ -429,8 +429,13 @@
   #else
     #define COUNT_PROBE_6 COUNT_PROBE_5
   #endif
-  #if COUNT_PROBE_6 > 1
-    #error "Please enable only one probe: FIX_MOUNTED_PROBE, Z Servo, BLTOUCH, Z_PROBE_ALLEN_KEY, or Z_PROBE_SLED."
+  #if ENABLED(Z_RACK_PINION)
+    #define COUNT_PROBE_7 INCREMENT(COUNT_PROBE_6)
+  #else
+    #define COUNT_PROBE_7 COUNT_PROBE_6
+  #endif  
+  #if COUNT_PROBE_7 > 1
+    #error "Please enable only one probe: FIX_MOUNTED_PROBE, Z Servo, BLTOUCH, Z_PROBE_ALLEN_KEY, Z_PROBE_SLED, or Z_RACK_PINION."
   #endif
 
   /**
@@ -491,7 +496,7 @@
    * Require some kind of probe for bed leveling and probe testing
    */
   #if HAS_ABL
-    #error "Auto Bed Leveling requires a probe! Define a Z Servo, Z_PROBE_ALLEN_KEY, Z_PROBE_SLED, or FIX_MOUNTED_PROBE."
+    #error "Auto Bed Leveling requires a probe! Define a Z Servo, Z_PROBE_ALLEN_KEY, Z_PROBE_SLED, FIX_MOUNTED_PROBE, or Z_RACK_PINION."
   #elif ENABLED(Z_MIN_PROBE_REPEATABILITY_TEST)
     #error "Z_MIN_PROBE_REPEATABILITY_TEST requires a probe! Define a Z Servo, Z_PROBE_ALLEN_KEY, Z_PROBE_SLED, or FIX_MOUNTED_PROBE."
   #endif