Print stopped due to serial error

Hi all,

After many successful prints using octoprint today I had a print stop due to a serial connection error (SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?).

I've already checked the FAQs regarding this issue and I think it was probably a USB power issue due to my camera (Kaiser Baas X250). I'll consider get an externally powered USB HUB and/or switching cameras, but in the meantime I had some questions I'd appreciate if anyone could help me with:

  1. Is there any way to confirm this "diagnosis"? Anything I can look for in the octoprint.log file? (I've attached it to this thread)
  2. In case this happens again, is there any safe and easy way to resume the print? I may me missing something, but when I noticed it had stopped I simply clicked "connect" and all was well again. Since octoprint knows where it stopped, I'm guessing it should be possible to simply resume the print?
  3. If this is indeed a USB power issue due to the camera
    3.1 Will reducing the streaming resolution and/or frame rate help?
    3.2 Will disabling the timelapse function and/or decreasing the frequency of the snapshots help?
    3.3 Is the number of connected web clients (ie: browsers open and getting the stream from octopi) relevant?
  4. I see octoprint allows me to upload the .gcode to the printer's SD card. It is possible to make the printer print from the SD card (through an octoprint instruction), so this issue doesn't result in other failed prints? Is there any downside of doing that?

I've attached the log file in case it helps.

Thanks in advance

octoprint.log (16.7 KB)

Well you got no undervoltage warning in this log. You might check older logs.

There is unfortunately no safe and easy way to resume your print. We don't know at what exact position the print stopped. We just know which gcode was sent before the disconnect happened (well hat least if serial logging is enabled). But the printer got a buffer so we don't know which command was the last executed and if it was fully executed. Also you have to home the printer with your print on the bed which is probably impossible.

I don't know if webcams need more power on higher resolutions.
Of course do snapshots cause a bit higher system load but I don't think it would make any difference.

Yeah you can upload it to an sd card but I would do it by hand with a card reader. The transfer speed is very slow and it takes ages for lager gcode files.
The downside is some octopi features don't work with sd prints. For example the snapshot after layer change doesn't work iirc. But a snapshot every X seconds still works.

First thing we suggest for serial errors is to switch the usb cable. A quality cable with ferrite beads is recommended. Don't use those blue cables that come with some china electronics.

First thing we suggest for serial errors is to switch the usb cable

I suppose you mean the USB cable connecting the PI to the printer? I'm using the original cable that came with the printer, so I suppose that shouldn't be the problem :\

I can't tell you how good it is.
If it happened the first time you could ignore it and hope for the best :woman_shrugging:

Alright, I think I'll just proceed with the camera replacement which I already intended to do. If it happens again I'll try switching the USB cable

Thanks for the help