Extruder drive lag with toolboard

kuon

Ok, after tinkering and trying to understand what was causing the issue, I found it. It's the hot end fan.

I did more tests and realized that under some conditions, I did not have the issue with either carriage. And finally, I pin pointed it to fan.

If the temperature is above 45° on the carriage and fan on -> issue
If below and fan off -> no issue. (45° is what I configured with M106).

dc42

Are you quite sure it is the fan causing the trouble, not the heater?

kuon

@dc42 Yes, because if I put the temp at 50, no issue until the fan is on (I ran the macro two times between 30 and 45°). Then I turned the heater off, and let it cool. Issue was present until fan turned off.

dc42

What sort of fan is it? Does the other tool use the same type of fan?

kuon

I made a video, it is not very good because it is hard to film, but we can clearly see the extruder drive turning at the end of the moves.

https://imgur.com/a/JqvbmAP

kuon

@dc42 https://www.digikey.ch/product-detail/en/delta-electronics/AUB0412VD-00/603-2091-ND/8680959

Both tools have the same fan, and the problem is present on BOTH tools with the fan on. I was just doing my test with one hot and one cold when I was trying to understand the initial issue.

kuon

I just realized I have another issue (which is surely totally unrelated but as I just noticed it, I put it here), is that when I move the X carriage all the way with a single G0 or G1 (like G0 X250 F12000), the carriage will slow down around the middle. https://imgur.com/a/z1gqYpY

If I do the same command with the U axis, I do not have the issue, but if I change to the second tool (the one using U axis), and do it on the mapped X axis (so the second carriage moves), the issue is also present with the second carriage. This issue is always present regardless of fan states.

kuon

@kuon said in Extruder drive lag with toolboard:

I just realized I have another issue (which is surely totally unrelated but as I just noticed it, I put it here), is that when I move the X carriage all the way with a single G0 or G1 (like G0 X250 F12000), the carriage will slow down around the middle. https://imgur.com/a/z1gqYpY

If I do the same command with the U axis, I do not have the issue, but if I change to the second tool (the one using U axis), and do it on the mapped X axis (so the second carriage moves), the issue is also present with the second carriage. This issue is always present regardless of fan states.

Just realized this issue is present only if I load bed compensation with G29 S1 (might not be a bug).

Stephen6309

@kuon You need to increase the set maximum instantaneous speed change or jerk for the Z axis.

kuon

@Stephen6309 Ok that makes sense, thanks.

kuon

Just to confirm the fans are the issue, I configured them as manual with M106, and when everything is cold, I can clearly "turn the issue on/off" with the fans, but only if it is being PWMed, at 0 or 100% the issue is not here.

Veti

@kuon
some fans do not like to run with pwm.

you can try changing the frequency, but it might not work.

dc42

@kuon, please can you update both main and tool board firmware to 3.2beta4.1 and check whether the problem still exists.

kuon

It took me a while to update everything, but I got everything on latest version.

Just a note, while updating I got two issues:

When doing apt-get upgrade I had this error, but it seems the update went through:

Sending update request to DCS... Error: Failed to send update request
Unhandled exception. System.Threading.Tasks.TaskCanceledException: A task was canceled.
   at DuetAPIClient.BaseConnection.PerformCommand[T](BaseCommand command, CancellationToken cancellationToken) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetAPIClient/BaseConnection.cs:line 188
   at DuetControlServer.Program.CheckForAnotherInstance() in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Program.cs:line 306
   at DuetControlServer.Program.Main(String[] args) in /home/christian/Duet3D/DuetSoftwareFramework/src/DuetControlServer/Program.cs:line 84
   at DuetControlServer.Program.<Main>(String[] args)
Aborted
Process

Duet3Bootloader-SAMC21.bin was not present after apt-get upgrade (on unstable) and I had to CURL it.

Anyway, now with this version I don't see the issue anymore. I will do some more tests and keep you updated.

kuon

Ok, while it made the problem less obvious, the issue is till here.

I thought things where OK, but when printing, I see some oozing https://imgur.com/a/hHgzC6X . If I put the fans at 100% without PWM, the issue is fixed.

The oozing is caused because the extrusion is slightly "late". When watching closely, I can clearly hear the filament retraction sound about 300ms after the z-hop sound.

For now I will run my fans at 100%. But I am very curious at what is causing the issue. I will certainly replace them for noctua fans that have proper PWM.

dc42

That's very strange. As on all Duet boards, the PWM is generated by hardware, so the load on the processor is the same whether the PWM is zero or 100% or anything in between.

kuon

@dc42 said in Extruder drive lag with toolboard:

That's very strange. As on all Duet boards, the PWM is generated by hardware, so the load on the processor is the same whether the PWM is zero or 100% or anything in between.

If you want me to run some tests just let me know. I fixed it by running my fans at 100% all the time, but it's noisy, so if I can PWM them a bit, I'd be happy.