Add Z_SERVO_INTERMEDIATE_STOW and measuring angle for servo probe

Marlin/Configuration.h

@@ -950,9 +950,16 @@
 
 /**
  * Z Servo Probe, such as an endstop switch on a rotating arm.
+ *
+ * The Z_SERVO_MEASURE_ANGLE is only useful if your servo needs to
+ * move to a "free" position to allow measuring.
+ * With Z_SERVO_INTERMEDIATE_STOW you can have the probe stowed
+ * between different points of a G29.
  */
-//#define Z_PROBE_SERVO_NR 0       // Defaults to SERVO 0 connector.
-//#define Z_SERVO_ANGLES { 70, 0 } // Z Servo Deploy and Stow angles
+//#define Z_PROBE_SERVO_NR 0          // Defaults to SERVO 0 connector.
+//#define Z_SERVO_ANGLES { 70, 0 }    // Z Servo Deploy and Stow angles
+//#define Z_SERVO_MEASURE_ANGLE 45    // Z Servo Angle after deploy (to allow measuring)
+//#define Z_SERVO_INTERMEDIATE_STOW   // Stow the probe between points
 
 /**
  * The BLTouch probe uses a Hall effect sensor and emulates a servo.

Marlin/src/gcode/bedlevel/abl/G29.cpp

@@ -420,7 +420,7 @@ G29_TYPE GcodeSuite::G29() {
 
     // Deploy certain probes before starting probing
     #if HAS_BED_PROBE
-      if (ENABLED(BLTOUCH))
+      if (ANY(BLTOUCH,Z_SERVO_INTERMEDIATE_STOW))
         do_z_clearance(Z_CLEARANCE_DEPLOY_PROBE);
       else if (probe.deploy()) {
         set_bed_leveling_enabled(abl_should_enable);

Marlin/src/module/probe.cpp

@@ -319,7 +319,17 @@ FORCE_INLINE void probe_specific_action(const bool deploy) {
 
   #elif HAS_Z_SERVO_PROBE
 
-    MOVE_SERVO(Z_PROBE_SERVO_NR, servo_angles[Z_PROBE_SERVO_NR][deploy ? 0 : 1]);
+    #ifdef Z_SERVO_MEASURE_ANGLE
+      if (deploy) {
+        //  First deploy, then move servo back to measure angle ...
+        MOVE_SERVO(Z_PROBE_SERVO_NR, servo_angles[Z_PROBE_SERVO_NR][0]);
+        MOVE_SERVO(Z_PROBE_SERVO_NR, Z_SERVO_MEASURE_ANGLE);
+      } else {
+        MOVE_SERVO(Z_PROBE_SERVO_NR, servo_angles[Z_PROBE_SERVO_NR][1]);
+      }
+    #else
+      MOVE_SERVO(Z_PROBE_SERVO_NR, servo_angles[Z_PROBE_SERVO_NR][deploy ? 0 : 1]);
+    #endif
 
   #elif EITHER(TOUCH_MI_PROBE, Z_PROBE_ALLEN_KEY)
 
@@ -487,6 +497,9 @@ bool Probe::probe_down_to_z(const float z, const feedRate_t fr_mm_s) {
   #endif
 
   if (TERN0(BLTOUCH_SLOW_MODE, bltouch.deploy())) return true; // Deploy in LOW SPEED MODE on every probe action
+  #if ANY(Z_SERVO_MEASURE_ANGLE, Z_SERVO_INTERMEDIATE_STOW)
+    probe_specific_action(true);  //  Always re-deploy in this case
+  #endif
 
   // Disable stealthChop if used. Enable diag1 pin on driver.
   #if ENABLED(SENSORLESS_PROBING)
@@ -528,6 +541,10 @@ bool Probe::probe_down_to_z(const float z, const feedRate_t fr_mm_s) {
   if (probe_triggered && TERN0(BLTOUCH_SLOW_MODE, bltouch.stow())) // Stow in LOW SPEED MODE on every trigger
     return true;
 
+  #if ENABLED(Z_SERVO_INTERMEDIATE_STOW)
+    probe_specific_action(false);  //  Always stow
+  #endif
+
   // Clear endstop flags
   endstops.hit_on_purpose();