thinkyhead

M851 - XYZ Probe Offset

none Set the Z probe XYZ offset from nozzle HAS_BED_PROBE

Description

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.

Notes

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)

Usage

M851 [X<linear>] [Y<linear>] [Z<linear>]

Parameters

[X<linear>]

Z probe X offset

[Y<linear>]

Z probe Y offset

[Z<linear>]

Z probe Z offset

Examples

Set a reasonable offset for an inductive probe

M851 Z-2.0

A probe that is triggered by the nozzle itself

M851 Z1.2

Set the XY distance (probe left front of nozzle)

M851 X-1.70 Y-1.30

Set the XY distance (probe right back of nozzle)

M851 X0.20 Y.40