Mesh calibration always outside printbed

vcaldas

Hi guys,

DuetMaestro/Firmware3.2-beta/

I manage to get the homing with a BLTouch working.
The endstops are set and the printer is measuring correctly the distances.

Howerver, if I run mesh compensation (G29), the probe always start outside the printbed.
It seems that it is ignoring M557

This is what I have on config.g
; Z-Probe
M950 S0 C"^zprobe.mod" ; create servo pin 0 for BLTouch
M558 P9 C"^zprobe.in" H5 F240 T6000 ; set Z probe type to bltouch and the dive height + speeds
G31 P500 X35 Y35 Z0.1 ; set Z probe trigger value, offset and trigger height
M557 X35:200 Y35:200 S55 ; define mesh grid

I will be happy to provide all the files. Any suggestion on where to start?

Veti

@vcaldas

the rest of the config file would help

if you go to X0 Y0 is the nozzle on the bottom left corner of the bed?

is your prove 35 milimeter to the right of the nozzle and 35mm behind?

vcaldas

@Veti
Adding the config fileconfig (2).g

If I go to X0 Y0, the nozzle is exactly at the corner of the printbed and the probe is out of the printbed.
If I go to X35 Y35 , then both are where they should be.

Veti

@vcaldas

M208 X220 Y220 Z210 S0 ; set axis maxima
G31 P500 X35 Y35 Z0.1 ; set Z probe trigger value, offset and trigger height
M557 X35:200 Y35:200 S55 ; define mesh grid

There is your problem 200+35 = 235

that is larger than your bed.

vcaldas

@Veti Thanks for the suggestion.

I changed to X50:150 S50 So it is now for sure smaller than the bed and is still having the same issue.
It's not zeroing on X50 for mesh levelling, but on X0 Y0

..

Veti

@vcaldas said in Mesh calibration always outside printbed:

It's not zeroing on X50 for mesh levelling, but on X0 Y0

what do you mean by zeroing?

vcaldas

Sorry for lack of clarification.
Zeroing was the first point to be probed.

I would expect the probe starts at X50 Y50 but it is going again to X0 Y0

Veti

@vcaldas

did you change y as well. it has the same problem as x

did you restart after the changes?

vcaldas

Yes. Both X and Y and giving the same error.
I restarted the machine, Checked the files, all is updated.

I even put the printer and X40 Y40 and I would expect to be on X50 Y50... it went directly to X0 Y50...

Not sure what to do...

Veti

@vcaldas
post your changed config

vcaldas

@Veti Found the issue!

G31 P500 X35 Y35 Z0.1 ; set Z probe trigger value, offset and trigger height

I was adding the offsets for X and Y as well and they should be 0
The new line becomes

G31 P500 X0 Y0 Z0.1 ; set Z probe trigger value, offset and trigger height

Problem solved!
Thanks for the patience and help!

Veti

@vcaldas said in Mesh calibration always outside printbed:

G31 P500 X0 Y0 Z0.1 ; set Z probe trigger value, offset and trigger height

no this is incorrect for a bltouch. this means that the nozzle would be the probing point. this will give you an incorrect mesh.

vcaldas

@Veti that's a very good point.

Fixing it to the correct values, there is no more error.
G31 P500 X-22 Y0 Z0.1

Thanks for pointing that out!