[3.6.0 RC1] MultiMotor Z bed leveling

[dc42]

@cichaczech please can you run levelling with 3.6.0-rc.1 again and this time observe the leadscrews to check whether they actually move when they are supposed to make the corrections. Also please try firmware 3.6.0-rc.1+3 available at https://www.dropbox.com/scl/fo/geqmn8gbn97n6b587mkbk/AJ2hBIqO-L57_QpR_uqHJ9c?rlkey=fw37wycbp2gil8rvxhe7aopy7&dl=0.

[cichaczech]

@dc42 leadscrews moves after last G30 P..... S command normaly in 3.6.0 RC1.

Here are my test first 3.6.0 RC1:

then I run 3.5.4 just to test it again:

and then 3.6.0RC1+3:

same printer, gcodes and same conditions - bed 70C hotend 230C.

[dc42]

@cichaczech please can you add a G4 S1 command after the G30 command with S parameter and see if it makes any difference. Unfortunately I don't have a machine with multiple Z leadscrews to test this on.

[cichaczech]

@dc42 still the same with G4 S1 after last G30. I have another printer with 3x Z motors and bed 240x240mm, but it still printing. I will post update when it finishes.

[cichaczech]

@dc42 so on 2nd printer both firmwares (3.5.4 and 3.6.0 RC1+3) works same, 3.6. mayby bit better. I suspect some problem with Duet2 board on 1st printer. Tomorow I will try flash it with BOSSA.

Sorry for bothering you whole week.

[dc42]

@cichaczech do both printers use Duet 2 ?

[cichaczech]

@dc42 yes and same configuration. One is just bigger and one smaller. I remember that one time I had some problems with Duet 2 in bigger printer and flash FW with bossa helped me. (I completly forgot abou it)

Update:
No change after BOSSA. Bed is still drifting away.

May there be problem with Bltouch? I do not know.

[Phaedrux]

@cichaczech said in [3.6.0 RC1] MultiMotor Z bed leveling:

May there be problem with Bltouch? I do not know.

One way to check that would be to switch to probe type 0 (M558 P0) to use manual probing where you get prompted to jog the nozzle down to touch the bed. This would isolate any bltouch issues.

[cichaczech]

@dc42 Today, I noticed an issue when using G30 the print head with the probe shifts a few millimeters to the right (+X axis) between multiple probing actions and after probing the reported X position in DWC is lower.

Example:

G28 X Y
G0 X113 Y200 ;move to bed center
G30 ;probe

1. The first probe is at X113 Y200 as expected.
2. When the bed moves away from the probe, the toolhead slightly shifts to +X before probing again.
   3.After probing, DWC updates the X position incorrectly—showing X111.3, even though physically, the tool is still past X113.

2 problems - probe moves between multiple probing and DWC reports wrong axis movment.

This happens on both of my CoreXY printers running firmware 3.6.0.

@Phaedrux I didn't have time to probe it manually today, but I'll try it tomorrow.

[dc42]

@cichaczech are you using M556 axis skew compensation?

How much does the X position shift after probing? It may help if you post a video.

[cichaczech]

@dc42 Yes, I do use M556. It should be in the config I posted earlier, but I just realized I copied the wrong one, sorry! I'll update it right now.

Desktop 2025.03.31 - 20.00.53.04.mp4