G29 first probe point not where expected

dbrb2

I have a coreXY printer with a duet2 wifi board
Board: Duet 2 WiFi (2WiFi)
Firmware: RepRapFirmware for Duet 2 WiFi/Ethernet 3.4.1 (2022-06-01)
Duet WiFi Server Version: 1.23

The Z probe is inductive, and offset by 40mm in the X direction from the hot-end

I can home all axes fine - however, if I try to run G29 - bed compensation, the first probe point the head moves to shows up in DWC as X=10, Y=30

Unfortunately this puts the inductive probe 30mm off the edge of the bed - so the head crashes

I do not have a bed.g file
In the config.g I have:

M557 X50:250 Y50:250 S20

I thought this would mean the first probe point, when I ran G29, would be X=50, Y=50...any idea why it is not?

jay_s_uk

@dbrb2 that's correct. You give it the coordinates of where you want the heightmap to be and then it applies the probe offset
You should probably adjust your M208 minima. E.g. if you nozzle is 20mm off the bed when coming into contact with the endstop then set the minima as X-20. This way X0 is the edge of the bed.

dbrb2

@jay_s_uk Thanks

I defined the Z probe offset as follows (also in config.g):

G31 P500 X40 Y20 Z0.53                  ; set Z probe trigger value, offset and trigger height

At the endstop position (X=0) the nozzle is just on the edge of the bed - however this puts the Z-probe off the bed by ~40mm

jay_s_uk

@dbrb2 hold on, if your probe has an offset of X40, then it should be 40mm to the right of the nozzle. If its off the bed by 40mm then it should be X-40

dbrb2

@jay_s_uk Ah....yes I may simply have my signage inverted....let me try that!
.....goes to try it....

Yes, that was it! How embarrassing! Thanks for the steer though!