machines/systems/flexibot/docs/marlin/_gcode/M851.md

tag	title	brief	author	requires	group	codes	notes	parameters	examples
m0851	XYZ Probe Offset	Set the Z probe XYZ offset from nozzle	thinkyhead	HAS_BED_PROBE	none	M851	The default (factory) values are set by - (version 1.x) - `X_PROBE_OFFSET_FROM_EXTRUDER` - `Y_PROBE_OFFSET_FROM_EXTRUDER` - `Z_PROBE_OFFSET_FROM_EXTRUDER` - (version 2.x) - `NOZZLE_TO_PROBE_OFFSET` and are integer values. Positions: X offset: -left +right [of the nozzle] Y offset: -front +behind [the nozzle] Z offset: -below +above [the nozzle] ```   +-- BACK ---+   |     | L | (+) P | R <-- probe (20,20) E | | I F | (-) N (+) | G <-- nozzle (10,10) T | | H   | (-) | T   | |   O-- FRONT --+  (0,0) ```	tag optional description values X true Z probe X offset unit type linear float tag optional description values Y true Z probe Y offset unit type linear float tag optional description values Z true Z probe Z offset unit type linear float	pre code Set a reasonable offset for an inductive probe M851 Z-2.0 pre code A probe that is triggered by the nozzle itself M851 Z1.2 pre code Set the XY distance (probe left front of nozzle) M851 X-1.70 Y-1.30 pre code Set the XY distance (probe right back of nozzle) M851 X0.20 Y.40

Set the XYZ distance from the nozzle to the probe trigger-point.

The easiest way to get the Z offset value is to:

• Home the Z axis.
• Raise Z and deploy the probe.
• Move Z down slowly until the probe triggers.
• Take the current Z value and negate it. (5.2 => -5.2)
• Set with M851 Z-5.2 and #define Z_PROBE_OFFSET_FROM_EXTRUDER -5.2.

For X and Y you have to measure the distance.