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@DerAndere1 DerAndere1 commented Nov 2, 2025

Description

G38 (probe target) integration into probes.h/cpp and more unified probing logic.
allow all probe types, PROBING_TOOL, offsets, Z_PROBE_ERROR_TOLERANCE, handle deploy/stow.

Tips:

For a spindle-mounted probe aka 3D finder / 3D sensor like those used in industrial machining centers: When #27614 will be merged, the probe can be set up as an additional tool. It can already be be set up as an additional dummy extruder as follows:

#define EXTRUDERS 3
#define G38_PROBE_TARGET
#define PROBING_TOOL 2 // Extruder 0 is for the empty spindle, dummy extruder 2 is for the probe
#define HOTEND_OFFSET_X {0, 0, 0}  
#define HOTEND_OFFSET_Y {0, 0, 0}  
#define HOTEND_OFFSET_Z {0, -60, -80} // Probe trigger point is 80 mm below T0 reference point (gauge line / bottom of empty spindle)   
#define NOZZLE_TO_PROBE_OFFSET {0, 0, -80} // Probe trigger point is 80 mm below T0 (gauge line / bottom of empty spindle)

Before sending G38, it is recommended to have trusted axis positions. Axis positions are trusted after homing (G28) until steppers power off.
Before and after G38 it is recommended to send an explicit tool change command:

G28 ; home all axes
T2 ; probing tool
G0 X10 Y10 Z60; starting position
G38.2 Y20 Y20 Z0 F200; probe target
T1 ; FDM 3D-printing nozzle, 0.4 mm diameter

Requirements

G38_PROBE_TARGET, any probe (NOZZLE_AS_PROBE / SENSORLESS_PROBING should also work)

Benefits

  • unified code paths for all probing actions where possible
  • G38 behaves more like other probing actions:
  • all probe types supported (including SENSORLESS_PROBING)
  • G38 respects PROBING_TOOL, NOZZLE_TO_PROBE_OFFSET, HOTEND_OFFSET_[X/Y/Z]
  • automatic tool change
  • automatic deploy, probe-specific stow

General improvements:

  • SOLENOID_PROBE: no more false-positive triggering of the probe during stow/deploy
  • No more "Probe Triggered early" debug message when Z raises because probe did not trigger
  • "Probe Triggered early" check properly accounts for nozzle-to-probe offset and hotend offset.

Configurations

None

Related Issues

#28087
#10861
#26887

@DerAndere1 DerAndere1 force-pushed the g38_probe_offset branch 16 times, most recently from 1155616 to 76833d4 Compare November 3, 2025 00:39
@DerAndere1 DerAndere1 force-pushed the g38_probe_offset branch 5 times, most recently from cb44538 to b461078 Compare November 11, 2025 22:25
@DerAndere1 DerAndere1 marked this pull request as ready for review November 12, 2025 14:20
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