Simplify PLR on pause

Author: thinkyhead

Marlin/src/feature/pause.cpp

@@ -419,9 +419,12 @@ bool pause_print(const_float_t retract, const xyz_pos_t &park_point, const bool
     unscaled_e_move(retract, PAUSE_PARK_RETRACT_FEEDRATE);
   }
 
-  // Park the nozzle by moving up by z_lift and then moving to (x_pos, y_pos)
-  if (!axes_should_home())
+  // Park the nozzle by doing a Minimum Z Raise followed by an XY Move
+  float park_raise = 0;
+  if (!axes_should_home()) {
+    park_raise = nozzle.park_mode_0_height(park_point.z) - current_position.z;
     nozzle.park(0, park_point);
+  }
 
   #if ENABLED(DUAL_X_CARRIAGE)
     const int8_t saved_ext        = active_extruder;
@@ -439,14 +442,8 @@ bool pause_print(const_float_t retract, const xyz_pos_t &park_point, const bool
   // Disable the Extruder for manual change
   disable_active_extruder();
 
-  #if ENABLED(POWER_LOSS_RECOVERY)
-    if (was_sd_printing && recovery.enabled) {                  // For an SD print
-      const xyze_pos_t tmp = current_position;
-      current_position = resume_position;
-      recovery.save(true, tmp.z - resume_position.z, true);
-      current_position = tmp;
-    }
-  #endif
+  // Save PLR info in case the power goes out while parked
+  TERN_(POWER_LOSS_RECOVERY, if (was_sd_printing && recovery.enabled) recovery.save(true, park_raise, true));
 
   return true;
 }

Marlin/src/feature/pause.h

@@ -89,14 +89,14 @@ extern uint8_t did_pause_print;
 bool pause_print(
   const_float_t   retract,                                    // (mm) Retraction length
   const xyz_pos_t &park_point,                                // Parking XY Position and Z Raise
-  const bool      show_lcd=false                              // Set LCD status messages?
-  const_float_t   unload_length=0,                            // (mm) Filament Change Unload Length - 0 to skip
+  const bool      show_lcd=false,                             // Set LCD status messages?
+  const_float_t   unload_length=0                             // (mm) Filament Change Unload Length - 0 to skip
   DXC_PARAMS                                                  // Dual-X-Carriage extruder index
 );
 
 void wait_for_confirmation(
   const bool      is_reload=false,                            // Reload Filament? (otherwise Resume Print)
-  const int8_t    max_beep_count=0,                           // Beep alert for attention
+  const int8_t    max_beep_count=0                            // Beep alert for attention
   DXC_PARAMS                                                  // Dual-X-Carriage extruder index
 );
 

Marlin/src/feature/powerloss.cpp

@@ -149,6 +149,8 @@ void PrintJobRecovery::prepare() {
  */
 void PrintJobRecovery::save(const bool force/*=false*/, const float zraise/*=0*/, const bool raised/*=false*/) {
 
+  // We don't check IS_SD_PRINTING here so a save may occur during a pause
+
   #if SAVE_INFO_INTERVAL_MS > 0
     static millis_t next_save_ms; // = 0
     millis_t ms = millis();
@@ -292,7 +294,8 @@ void PrintJobRecovery::save(const bool force/*=false*/, const float zraise/*=0*/
       constexpr float zraise = 0;
     #endif
 
-    // Save, including the limited Z raise
+    // Save the current position, distance that Z will be raised,
+    // and a flag whether the raise was already done here.
     if (IS_SD_PRINTING()) save(true, zraise, ENABLED(BACKUP_POWER_SUPPLY));
 
     // Disable all heaters to reduce power loss
@@ -368,22 +371,29 @@ void PrintJobRecovery::resume() {
     }
   #endif
 
-  // Reset E, raise Z, home XY...
+  //
+  // Home the axes that can safely be homed, and
+  // establish the current position as best we can
+  //
   #if Z_HOME_DIR > 0
 
-    // If Z homing goes to max, just reset E and home all
+    // If Z homing goes to max...
     gcode.process_subcommands_now_P(PSTR(
-      "G92.9 E0\n"
-      "G28R0"
+      "G92.9 E0\n"                          // Reset E to 0
+      "G28R0"                               // Home all axes (no raise)
     ));
 
   #else // "G92.9 E0 ..."
 
+    // Reset Z and E to 0
     gcode.process_subcommands_now_P("G92.9E0Z0");
 
-    // If a Z raise occurred at outage set Z to the Z raise value (over zero), otherwise raise Z now
-    sprintf_P(cmd, info.flag.raised ? PSTR("G92.9Z%s") : PSTR("G1Z%sF200"), dtostrf(info.zraise, 1, 3, str_1));
-    gcode.process_subcommands_now(cmd);
+    // Is there a "raise" value?
+    if (info.zraise) {
+      // If a Z raise occurred at outage set Z to the Z raise value, otherwise raise Z now
+      sprintf_P(cmd, info.flag.raised ? PSTR("G92.9Z%s") : PSTR("G1Z%sF500"), dtostrf(info.zraise, 1, 3, str_1));
+      gcode.process_subcommands_now(cmd);
+    }
 
     // Home safely with no Z raise
     gcode.process_subcommands_now_P(PSTR(
@@ -395,19 +405,20 @@ void PrintJobRecovery::resume() {
 
   #endif
 
-  #ifdef POWER_LOSS_ZHOME_POS
-    // If defined move to a safe Z homing position that avoids the print
+  #if ENABLED(POWER_LOSS_RECOVER_ZHOME) && defined(POWER_LOSS_ZHOME_POS)
+    // Move to a safe XY position where Z can home while avoiding the print.
+    // If Z_SAFE_HOMING is enabled, its position must also be outside the print area!
     constexpr xy_pos_t p = POWER_LOSS_ZHOME_POS;
-    sprintf_P(cmd, PSTR("G1 X%s Y%s F1000\nG28Z"), dtostrf(p.x, 1, 3, str_1), dtostrf(p.y, 1, 3, str_2));
+    sprintf_P(cmd, PSTR("G1X%sY%sF1000\nG28Z"), dtostrf(p.x, 1, 3, str_1), dtostrf(p.y, 1, 3, str_2));
     gcode.process_subcommands_now(cmd);
   #endif
 
-  // Ensure that all axes are marked as homed
+  // Mark all axes as having been homed (no effect on current_position)
   set_all_homed();
 
   #if ENABLED(POWER_LOSS_RECOVER_ZHOME)
-    // Now move to ZsavedPos + POWER_LOSS_ZRAISE
-    sprintf_P(cmd, PSTR("G1 Z%s F500"), dtostrf(info.current_position.z + POWER_LOSS_ZRAISE, 1, 3, str_1));
+    // Z was homed. Now move Z back up to the saved Z height, plus the POWER_LOSS_ZRAISE.
+    sprintf_P(cmd, PSTR("G1Z%sF500"), dtostrf(info.current_position.z + POWER_LOSS_ZRAISE, 1, 3, str_1));
     gcode.process_subcommands_now(cmd);
   #endif
 
@@ -447,7 +458,7 @@ void PrintJobRecovery::resume() {
     }
   #endif
 
-  // Restore retract and hop state
+  // Restore retract and hop state from an active `G10` command
   #if ENABLED(FWRETRACT)
     LOOP_L_N(e, EXTRUDERS) {
       if (info.retract[e] != 0.0) {
@@ -462,7 +473,7 @@ void PrintJobRecovery::resume() {
     // Restore leveling state before 'G92 Z' to ensure
     // the Z stepper count corresponds to the native Z.
     if (info.fade || info.flag.leveling) {
-      sprintf_P(cmd, PSTR("M420 S%i Z%s"), int(info.flag.leveling), dtostrf(info.fade, 1, 1, str_1));
+      sprintf_P(cmd, PSTR("M420S%cZ%s"), '0' + (char)info.flag.leveling, dtostrf(info.fade, 1, 1, str_1));
       gcode.process_subcommands_now(cmd);
     }
   #endif
@@ -472,11 +483,11 @@ void PrintJobRecovery::resume() {
   #endif
 
   // Un-retract if there was a retract at outage
-  #if POWER_LOSS_RETRACT_LEN
+  #if ENABLED(BACKUP_POWER_SUPPLY) && POWER_LOSS_RETRACT_LEN > 0
     gcode.process_subcommands_now_P(PSTR("G1 E" STRINGIFY(POWER_LOSS_RETRACT_LEN) " F3000"));
   #endif
 
-  // Additional purge if configured
+  // Additional purge on resume if configured
   #if POWER_LOSS_PURGE_LEN
     sprintf_P(cmd, PSTR("G1 E%d F3000"), (POWER_LOSS_PURGE_LEN) + (POWER_LOSS_RETRACT_LEN));
     gcode.process_subcommands_now(cmd);

Marlin/src/lcd/extui/lib/dgus/mks/DGUSDisplayDef.cpp

@@ -82,11 +82,15 @@ constexpr feedRate_t park_speed_xy = TERN(NOZZLE_PARK_FEATURE, NOZZLE_PARK_XY_FE
 void MKS_pause_print_move() {
   queue.exhaust();
   position_before_pause = current_position;
+
+  // Save the current position, the raise amount, and 'already raised'
+  TERN_(POWER_LOSS_RECOVERY, if (recovery.enabled) recovery.save(true, mks_park_pos.z, true));
+
   destination.z = _MIN(current_position.z + mks_park_pos.z, Z_MAX_POS);
   prepare_internal_move_to_destination(park_speed_z);
+
   destination.set(X_MIN_POS + mks_park_pos.x, Y_MIN_POS + mks_park_pos.y);
   prepare_internal_move_to_destination(park_speed_xy);
-  TERN_(POWER_LOSS_RECOVERY, if (recovery.enabled) recovery.save(true, mks_park_pos.z, true));
 }
 
 void MKS_resume_print_move() {

Marlin/src/libs/nozzle.cpp

@@ -225,6 +225,18 @@ Nozzle nozzle;
 
 #if ENABLED(NOZZLE_PARK_FEATURE)
 
+  float Nozzle::park_mode_0_height(const_float_t park_z) {
+    // Apply a minimum raise, if specified. Use park.z as a minimum height instead.
+    return _MAX(park_z,                       // Minimum height over 0 based on input
+      _MIN(Z_MAX_POS,                         // Maximum height is fixed
+        #ifdef NOZZLE_PARK_Z_RAISE_MIN
+          NOZZLE_PARK_Z_RAISE_MIN +           // Minimum raise...
+        #endif
+        current_position.z                    // ...over current position
+      )
+    );
+  }
+
   void Nozzle::park(const uint8_t z_action, const xyz_pos_t &park/*=NOZZLE_PARK_POINT*/) {
     constexpr feedRate_t fr_xy = NOZZLE_PARK_XY_FEEDRATE, fr_z = NOZZLE_PARK_Z_FEEDRATE;
 
@@ -237,15 +249,9 @@ Nozzle nozzle;
         do_blocking_move_to_z(_MIN(current_position.z + park.z, Z_MAX_POS), fr_z);
         break;
 
-      default: {
-        // Apply a minimum raise, overriding G27 Z
-        const float min_raised_z =_MIN(Z_MAX_POS, current_position.z
-          #ifdef NOZZLE_PARK_Z_RAISE_MIN
-            + NOZZLE_PARK_Z_RAISE_MIN
-          #endif
-        );
-        do_blocking_move_to_z(_MAX(park.z, min_raised_z), fr_z);
-      } break;
+      default: // Raise by NOZZLE_PARK_Z_RAISE_MIN, use park.z as a minimum height
+        do_blocking_move_to_z(park_mode_0_height(park.z), fr_z);
+        break;
     }
 
     do_blocking_move_to_xy(

Marlin/src/libs/nozzle.h

@@ -83,6 +83,7 @@ class Nozzle {
 
   #if ENABLED(NOZZLE_PARK_FEATURE)
 
+    static float park_mode_0_height(const_float_t park_z) _Os;
     static void park(const uint8_t z_action, const xyz_pos_t &park=NOZZLE_PARK_POINT) _Os;
 
   #endif