Machine not returning to the correct Z position after resuming

curieos · 23 Sept 2024, 15:41

We have a customer with this issue. I've been able to reproduce it, but I haven't determined the steps required to reproduce it.

Both our machines are on 3.5.2. It's two 6XDs and two 1LCs in SBC mode with a Pi 5, using the image from April. There is also a PanelDue running the latest firmware. It appears to occur when the filament monitor detects a jam on the second toolhead.

I have theories as to what happens. It appears that it occurs specifically when a jam is detected, the print is paused, and then the print is resumed by the user without clearing the jam. It then pauses again since the jam wasn't cleared. The user then resolves the jam, resumes the print, and an offset is observed.

It may also have to do with resuming from the PanelDue. I observed this issue, more easily repeatable, with a machine that had an out of date PanelDue. I have verified with the customer that the latest version of that firmware is installed, and during all of the observed events it was on 3.5.0.

I'm still attempting to replicate the issue repeatably. I know 3.5.3 is out, but I don't want to try it until I can make the issue occur intentionally.

timschneider · 23 Sept 2024, 16:21

@curieos do you use firmware retraction?

curieos · 23 Sept 2024, 16:35

I believe I have replicated it. I put M400s and echos into the pause and resume macros to get more useful information about user and machine position, but I think the M400s caused the issue to not happen.

It appears to occur regardless of how the machine is paused (filament monitor error or manual pause), or which interface resumes it. It appears that all it takes is one pause on the secondary tool. The ones I'm producing currently are small but noticeable, and don't occur without a pause. I believe multiple pauses create a larger shift.

I've confirmed pauses while the primary tool is active do not cause the shifting. I've also confirmed adding an M400 to the end of the resume.g file prevents this shift.

Configuration repo

@timschneider No, there are retractions in the pause and tool change files, but we do not use M207 and G10/11.