Function of "speed" slider/button on DWC/PanelDue?

NeoDue

I tried to use the "speed" slider (or rather the buttons controlling it) in DWC yesterday for the first time. The reason was to find a printer speed that makes the printer more silent since the print took longer than expected and you can hear some of the machine moves from our bedroom. Therefore my intention was to move down to 80%, then 70%, 60% 50% and listen a while.

1st observation: the buttons reacted rather laggy and the displayed value went down with each click by 5% (as it should be) but then went up again by 5% after maybe half a second or a little less.
2nd observation when I went so the printer: at one step it seemed the extruder speed got out of sync, if I interpret the result correctly: the print head moved perfectly fine, but the material that came out of the nozzle was just enough for cobwebs. When I increased speed again to 100%, more came out but still far from enough. The filament sensor did not cause the Duet to complain though even if it should.
I stopped the print and started a new one, and extrusion was still far from where it ought to be. A restart of the whole printer however immediately cured the issue.

For now, this is a one-time error which I need to recreate first, but I would like to know what those DWC buttons do to be able to check the values set by them via the console if that happens again to be able to file a decent bug report.

Could anyone explain this to me?

oliof

@NeoDue which RRF version is running on your printer and how is it set up? Any toolboards in the mix?

The speed slider just applies M220 https://docs.duet3d.com/User_manual/Reference/Gcodes#m220-set-speed-factor-override-percentage and I've never seen the extruder getting out of sync like you describe; one reason I can imagine this happens that if you reduce the speed and your printer suffers from insufficient hotend cooling, you may end up with heat creep from reduced flow.

NeoDue

@oliof It is still the same - IDEX, Duet 3 6HC and no toolboards, no SBC or such . I will add or link to everything in a possible bug report of course.

A clog or insufficient cooling was my first thought as well, but the Duet should have detected that within short due to the filament sensor that triggers every 2mm of filament. The amount of material that was or rather should have been printed was a generous multiple of that. Therefore and due to the fact that a start of another print after letting everything cool down did not cure the issue (while manual extrusion via PanelDue worked fine at the same time) but a reboot did, I am somewhat tempted to rule out something mechanical.

But I want to test more first before I bother the team here again, and if DWC really only sets an M220 or M221 value, this should be easy to confirm, hence the question.

droftarts

@NeoDue Is it possible you inadvertently moved the extruder multiplier slider, rather than the speed slider? They are perilously close to each other!

Ian

NeoDue

@droftarts Hm, on my mobile phone there are about 6cm distance and three fan sliders between them. I cannot fully rule it out since I admit I was tired at the moment, but I hope my brain was not that offline...

Currently I am printing the parts I need once more - this time without touching those sliders. When that is done, I can start testing

Just to be sure: can you confirm that the slider only sets M220?

droftarts

@NeoDue said in Function of "speed" slider/button on DWC/PanelDue?:

Just to be sure: can you confirm that the slider only sets M220?

I believe so, short of testing both DWC to see what it outputs, and testing M220 (I mean, it could have developed a bug...). The slider and M220 has worked okay for me in the past, but I haven't tested it specifically for a while.

Ian

NeoDue

@droftarts Thanks! I can only state that it did indeed work on my old printer as well (on 3.3 or an early 3.4 release). Let's see what some testing will yield.