Allow positive Z nozzle to probe offset (MarlinFirmware#20344)

* Allow a positive value for z offset from nozzle to probe without sanity checks
* Simplify menu_probe_offset.cpp (HOMING_Z_WITH_PROBE)
* Add some more explanation to Configuration Files
* Raise after probe_at_point as if homed

Co-authored-by: Scott Lahteine <[email protected]>
Co-authored-by: Jason Smith <[email protected]>

Author: 3 people

Marlin/Configuration.h

@@ -954,10 +954,20 @@
 /**
  * Nozzle-to-Probe offsets { X, Y, Z }
  *
- * - Use a caliper or ruler to measure the distance from the tip of
+ * X and Y offset
+ *   Use a caliper or ruler to measure the distance from the tip of
  *   the Nozzle to the center-point of the Probe in the X and Y axes.
+ * 
+ * Z offset
  * - For the Z offset use your best known value and adjust at runtime.
- * - Probe Offsets can be tuned at runtime with 'M851', LCD menus, babystepping, etc.
+ * - Common probes trigger below the nozzle and have negative values for Z offset.
+ * - Probes triggering above the nozzle height are uncommon but do exist. When using
+ *   probes such as this, carefully set Z_CLEARANCE_DEPLOY_PROBE and Z_CLEARANCE_BETWEEN_PROBES
+ *   to avoid collisions during probing.
+ * 
+ * Tune and Adjust
+ * -  Probe Offsets can be tuned at runtime with 'M851', LCD menus, babystepping, etc.
+ * -  PROBE_OFFSET_WIZARD (configuration_adv.h) can be used for setting the Z offset.
  *
  * Assuming the typical work area orientation:
  *  - Probe to RIGHT of the Nozzle has a Positive X offset

Marlin/Configuration_adv.h

@@ -1084,7 +1084,8 @@
     #if ENABLED(PROBE_OFFSET_WIZARD)
       //
       // Enable to init the Probe Z-Offset when starting the Wizard.
-      // Use the estimated nozzle-to-probe Z offset, plus a little more.
+      // Use a height slightly above the estimated nozzle-to-probe Z offset.
+      // For example, with an offset of -5, consider a starting height of -4.
       //
       //#define PROBE_OFFSET_WIZARD_START_Z -4.0
 

Marlin/src/inc/SanityCheck.h

@@ -1357,12 +1357,6 @@ static_assert(Y_MAX_LENGTH >= Y_BED_SIZE, "Movement bounds (Y_MIN_POS, Y_MAX_POS
     static_assert(sanity_nozzle_to_probe_offset.x == 0 && sanity_nozzle_to_probe_offset.y == 0,
                   "NOZZLE_AS_PROBE requires the XY offsets in NOZZLE_TO_PROBE_OFFSET to both be 0.");
   #else
-    static_assert(sanity_nozzle_to_probe_offset.z <= 0.25,
-                  "Are you sure your Probe triggers above the nozzle? Set a negative Z value in the NOZZLE_TO_PROBE_OFFSET.");
-    #ifdef PROBE_OFFSET_WIZARD_START_Z
-      static_assert(PROBE_OFFSET_WIZARD_START_Z <= 0.25,
-                    "Are you sure your Probe triggers above the nozzle? Set a negative value for PROBE_OFFSET_WIZARD_START_Z.");
-    #endif
     static_assert(PROBING_MARGIN       >= 0, "PROBING_MARGIN must be >= 0.");
     static_assert(PROBING_MARGIN_BACK  >= 0, "PROBING_MARGIN_BACK must be >= 0.");
     static_assert(PROBING_MARGIN_FRONT >= 0, "PROBING_MARGIN_FRONT must be >= 0.");

Marlin/src/lcd/menu/menu_probe_offset.cpp

@@ -107,8 +107,8 @@ void probe_offset_wizard_menu() {
 
   ACTION_ITEM(MSG_BUTTON_CANCEL, []{
     set_offset_and_go_back(z_offset_backup);
-    // If wizard-homing was done by probe with with PROBE_OFFSET_WIZARD_START_Z
-    #if EITHER(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN, USE_PROBE_FOR_Z_HOMING) && defined(PROBE_OFFSET_WIZARD_START_Z)
+    // If wizard-homing was done by probe with PROBE_OFFSET_WIZARD_START_Z
+    #if HOMING_Z_WITH_PROBE && defined(PROBE_OFFSET_WIZARD_START_Z)
       set_axis_never_homed(Z_AXIS); // On cancel the Z position needs correction
       queue.inject_P(PSTR("G28Z"));
     #else // Otherwise do a Z clearance move like after Homing
@@ -122,7 +122,7 @@ void probe_offset_wizard_menu() {
 void prepare_for_probe_offset_wizard() {
   if (ui.wait_for_move) return;
 
-  #if defined(PROBE_OFFSET_WIZARD_XY_POS) || NONE(Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN, USE_PROBE_FOR_Z_HOMING)
+  #if defined(PROBE_OFFSET_WIZARD_XY_POS) || !HOMING_Z_WITH_PROBE
     if (ui.should_draw()) MenuItem_static::draw(1, GET_TEXT(MSG_PROBE_WIZARD_PROBING));
 
     #ifndef PROBE_OFFSET_WIZARD_XY_POS
@@ -133,7 +133,7 @@ void prepare_for_probe_offset_wizard() {
 
     // Probe for Z reference
     ui.wait_for_move = true;
-    z_offset_ref = probe.probe_at_point(wizard_pos, PROBE_PT_STOW, 0, true);
+    z_offset_ref = probe.probe_at_point(wizard_pos, PROBE_PT_RAISE, 0, true);
     ui.wait_for_move = false;
 
   #endif