[3.6.0 RC1] MultiMotor Z bed leveling

[cichaczech]

Hello,

I have problem with auto bed levelig with 3 independent motors in FW 3.6.0. In version 3.5.4 it worked well, but with new FW rear motor keeps moving away from ideal plane with every auto leveling pass.

M561						; Vymaz predchozi zakriveni podlozky
G28 X Y  			        ; Home X Y axis
G0 X115 Y215		        ; 
G30 				        ; 
G4 S1				        ; 
G30 P0 X20 Y400 Z-99999     ; Zjisti vysku Leveho Zadniho rohu
G30 P1 X245 Y400 Z-99999    ; Zjisti vysku Praveho Zadniho rohu
G30 P2 X245 Y5 Z-99999      ; Zjisti vysku Praveho Predniho rohu
G30 P3 X20 Y5 Z-99999 S3    ; Zjisti vysku Leveho Predniho rohu a vyrovnej podlozku
G29					        ; Zmer zakriveni podlozky

in 3.5.4 :


heightmap(3.5.4).csv

in 3.6.0 RC1


heightmap(3.6RC1+2).csv

EDIT-
Config:

;########################### Komunikace #####################################
M552 S1														; Aktivuj Wifi modul, pripoj se na znamou Wifi
M586 P1 S1                                                  ; Enable FTP
M575 P1 B57600 S0											; Nastav seriovy port Baud 57600, no checksum
;_________________________________________________________________________
 
;####################################General preferences##########################################
 
M669 K1                                                     ; Select CoreXY mode
M550 P"CichyCore"						  	 ; Nastev jméno tiskarny
;M929 P"log.txt" S1                                         ; Start logging informations
;__________________________________________________________________________________________________
 
;###################################Drives##########################################################
M584 X0 Y1 Z5:6:7 E3:4:2					                ; Set Divers mapping Z-Front Left:Rear Center:Front Right, E-Left, Right, Head
M569 P0 S1                                                  ; Physical drive 0 goes forwards
M569 P1 S1                                                  ; Physical drive 1 goes forwards
M569 P2 S0                                                  ; Physical drive 2 goes backwards
M569 P3 S0                                                  ; Physical drive 3 goes backwards
M569 P4 S0                                                  ; Physical drive 4 goes forwards
M569 P5 S0                                                  ; Physical drive 5 goes forwards
M569 P6 S0                                                  ; Physical drive 6 goes forwards
M569 P7 S0                                                  ; Physical drive 7 goes forwards
 
M451                                                      ; Nastav FFF Mod
M671 X-68.8:131.2:331.2 Y-55.0:540.0:-55.0 S5             ; leadscrews at Front left, Rear center and Front right
M593 P"ei3" F54 S0.05                                   ; Input Shaping
 
M350 X16 Y16 Z16 E16:16:16 I1                      	        ; Configure microstepping with interpolation
M92  X100.000    Y100.000    Z3200.000 E96.55:96.55:96.55   ; Set steps per mm (16) [E=(microstep)*200/(pi*gear_dia)]
M350 E64:64:64 I0                                           ; Set extruders microstepping to 64 no interpolation
 
M566 X900        Y900        Z100       E2000.00:2000.00:2000.00    ; Set maximum instantaneous speed changes (mm/min)
M201 X10000      Y10000      Z120    E15000:9000:15000              ; Set accelerations (mm/s^2)
M203 X30000      Y30000      Z280      E30000:30000:30000           ; Set maximum speeds (mm/min))
M906 X1800       Y1800       Z1000     E1000:1000:600  I30          ; Set motor currents (mA) and motor idle factor in per cent
M84 S30                                                             ; Set idle timeout
 
M556 S1 X0.0044693 Y0.0013474 Z0.0051741 			    	        ; Orthogonal axis compensation with M556
M579 X1.003827 Y1.003116 Z0.998213      						    ; Scale compensation
;_______________________________________________________________________________________________________
 
;##############################Limity pohybu########################################
M208 X0 Y0 Z0 S1                                            ; Set axis minima
M208 X269 Y445 Z320 S0                                      ; Set axis maxima
M564 H0 S0                                                  ; Axis Limit H0 = allow movement of axes that have not been homed, S0 = allow movement outside boundaries
;________________________________________________________________________________________________________
 
;####################################Endstops#####################################                                              
M574 X1 S1 P"xstop"         ; X min active high endstop switch
M574 Y2 S1 P"!ystop"        ; Y max active high endstop switch
M574 Z2 S1 P"!exp.e3stop"   ; Z max active high endstop switch
M591 D0 P1 C"e0stop" S1     ; Extruder 0 Filament sensor, D- Drive, P-type of probe, C-pin name, S- filament monitoring
M591 D1 P1 C"e1stop" S1     ; Extruder 1 Filament sensor, D- Drive, P-type of probe, C-pin name, S- filament monitoring
M591 D2 P1 C"zstop" S1      ; Extruder 2 Filament sensor, D- Drive, P-type of probe, C-pin name, S- filament monitoring
;_________________________________________________________________________________
 
;################################## Vstup/Výstupy - výhrev/PWM ##############################
M950 F2 C"FAN2"     ;ventilator chlazeni Z Driveru a Elektroniky
M106 P2 S0          ;Vypni chladici ventilatory
 
 
############Hotend/Bed Heater################## ....
......
 
;##########################BLTouch############################
M558 P9 C"^zprobe.in" F200 H5 R0.5 T6000 A5 S0.03 B1					; Defien Probe - P-BLTouch, C-pin name&pin status, F-Probing speed mm/min, H-Dive height (mm), R-0,2 sec pause after probe, T-100mm/s move betwen probe points, A-Probe 5x or until 2 similar, B1-turn off heaters
M950 S6 C"!exp.heater6" 						         				; create servo/gpio 0 on heater 6 pin on expansion connector 
G31 P80 X20.0 Y3.0 Z1.685		                         				; Offset BLTouch od tiskove hlavy, P-Citlivost mereni
 
..
 
M557 X21:245 Y5:395 P4:5

Am I missing something?
Thank you,

[dc42]

@cichaczech you say that the rear motor is adjusted by a larger amount using RRF 3.6; however I see this for all 3 leadscrews. This is because the magnitude of the initial mean value is much greater in the data you post for 3.6rc1, i.e. 0.073 to 0.191mm (ignoring the first adjustment), compared to 0.002 to 0.008mm with 3.5.4.

Are you definitely using the same config.g file and bed.g file in both cases?

[cichaczech]

@dc42 Yes, first I did 3.5.4 -> 5x auto adjust and than G29. immediately after I upload 3.6.0 and run same 5x auto adjust and than G29. I am using same printer, Duet2, config and all gcodes in both examples.

[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