G30 during G28 issue

droftarts

@Leonard03 We are homing in on a bug, related to applying the skew compensation when axes are homed at the same time. In 3.5.4, this worked correctly, but now doesn't seem to.

The difference is in how the skew compensation is applied. "resurrect-prologue.g" needs to run just X and Y homing, it runs home X, then home Y. Skew compensation is applied to X once Y is homed. In homeall.g, X and Y are homed at the same time, but doesn't seem to apply skew compensation until after the first move, which is when the axes move to resume the print, so will be in the wrong place.

A workaround for now is to modify your homeall.g so it homes X, then Y, rather than both at the same time. Either replace the X and Y homing lines with the lines from homex.g and homey.g, or as @fcwilt mentioned earlier in this thread, replace them by calling the homex.g and homey.g macros, eg

M98 P"homex.g"
M98 P"homey.g"

Then it should resurrect in the same place. @dc42 is working on a fix.

Ian

Leonard03

@droftarts Interesting point of view. All right, I'm trying this now and report back

Leonard03

@droftarts Tried the suggested workaround
Umm.. I don't know what to say
I've modified the homeall.g from:

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.2.0 on Tue Dec 29 2020 16:23:44 GMT+0200 (Eastern European Standard Time)

G91							; relative positioning
G1 H2 Z5 F6000				; lift Z relative to current position
G1 H1 X-320 Y-306 F1800		; move quickly to X and Y axis endstops and stop there (first pass)
G1 X5 Y5 F6000				; go back a few mm
G1 H1 X-320 Y-306 F240		; move slowly to X and Y axis endstops once more (second pass)
G1 H1 Z-405 F240			; move Z down stopping at the endstop

G90							; absolute positioning
G1 Z5
G1 X{(310/2)-sensors.probes[0].offsets[0]} Y{(310/2)-sensors.probes[0].offsets[1]} F6000
G30
G1 X0 Y0

if global.MMUmode = true
	M98 P"0:/sys/MMU Control/homeMMU.g"

to

; homeall.g
; called to home all axes
;
; generated by RepRapFirmware Configuration Tool v3.2.0 on Tue Dec 29 2020 16:23:44 GMT+0200 (Eastern European Standard Time)

M98 P"homex.g"
M98 P"homey.g"
G1 H1 Z-405 F240			; move Z down stopping at the endstop

G90							; absolute positioning
G1 Z5
G1 X{(310/2)-sensors.probes[0].offsets[0]} Y{(310/2)-sensors.probes[0].offsets[1]} F6000
G30
G1 X0 Y0

if global.MMUmode = true
	M98 P"0:/sys/MMU Control/homeMMU.g"

Is an improvement, still shifted but way less then before

From left to right: No skew compensation, in homeall.g homing both X and Y at the same time and the last is calling independent macros in homeall.g
The shift is reduced from 2mm to 1mm

Update: if during a pause I rehome X or Y the print resume at the right position

droftarts

@Leonard03 Okay, thanks for testing! Back to the drawing board...

Ian

Leonard03

@droftarts sorry...

droftarts

@Leonard03 Are you still using RRF 3.6.0-rc3+2 firmware?

Ian

Leonard03

@droftarts Yes, 3.6.0-rc.3+2 (2025-05-19 11:46:09)

dc42

@Leonard03 please try this firmware.

Duet2CombinedFirmware.bin

Leonard03

@dc42 Thank you very much! I confirm that this issue is solved! Works very ewll
Also, thank you to everyone for every input and all the support !

dc42

@Leonard03 thanks for your feedback and for testing all these firmware builds.