Probe XY offset - Best Practice?

JohnOCFII

Greetings,

In the files delivered with the T3P3 Kossel Mini v3, the G31 X and Y offsets are set to 0, and the comment implies that is intended:

config.g

[[language]]
G31 X0 Y0 Z1.8 P500			; Set the zprobe offset and threshold (put your own values here). For a delta, use zero X and Y offset and measuere Z.

bed.g

[[language]]
G31 X0 Y0		; don't want any probe offset for this

But the X and Y offset is entered into the actual probe points in bed.g:

bed.g

[[language]]
; Probe the bed and do 6- or 7-factor auto calibration
; bed.g file for RepRapFirmware generated by http://escher3d.com/pages/wizards/wizardbed.php
; 10 points, 6 factors, probing radius: 85, probe offset (11, 0)

Is this still the preferred approach, as opposed to setting X and Y probe offsets in config.g's G31 command?

Thanks,

John

JohnOCFII

Any suggestions on the most preferred way to represent XY probe offset?

Thanks,

John

dc42

The comment about setting the probe offset to zero for a delta is obsolete. Unless you are using very old firmware, you should use the actual probe offset in config.g and not change it in bed.g.

JohnOCFII

@dc42:

The comment about setting the probe offset to zero for a delta is obsolete. Unless you are using very old firmware, you should use the actual probe offset in config.g and not change it in bed.g.

Thanks for the clarification, David.

JohnOCFII

@dc42:

The comment about setting the probe offset to zero for a delta is obsolete. Unless you are using very old firmware, you should use the actual probe offset in config.g and not change it in bed.g.

Thanks again - I just noticed this advice about XY in G31 is still in the Wiki - you might wish to update: https://www.duet3d.com/wiki/Configuring_RepRapFirmware_for_a_Cartesian_printer

The G31 command also has also optional X and Y parameters to define the horizontal offset of the Z probe from the nozzle. On a delta printer these should be left at zero, because the calibration routine needs to know where the nozzle has been placed, not where the probe is.

dc42

Thanks, I've just updated it.