i get the ..I guess famous Serial connections Error on my Ender 3 with Marlin 2.0.7:
"
Unexpected error while reading serial port, please consult octoprint.log for details: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:3860
Please see OctoPrint randomly loses connection to the printer with a "SerialException" - FAQ - OctoPrint Community Forum for possible reasons of this.
Changing monitoring state from "Printing" to "Offline after error"
Connection closed, closing down monitor "
I already checked the PI for undervoltage but there is no such Icon or Issiue in the logs (I had these problems in the past but it never led to an serial connection problem) Further when I print via octorpint in a virtual maschine it does it without any problem, therefore I can rule out an broken cable or something with the printer itself.
Of Course my cable is "modified" and the +5V pin is covered mit electrical tape.
I am not sure what else to check. I already reinstalled Octoprint on an fresh SD Card and I am without a clue.
I think still this could be a power Problem , because the PI is powered by a buck converter in the micro USB port.
Can I add an capacitor to rule out any fluctuations with the power supply?
your description skipped the part with the haptic data but from the log it appears the printer stops mid-print and all is lost.
Which is unfortunate.
Two thoughts:
what does dmesg report (called immediately after the havoc and only the last few lines are of interest but I think you can tell that apart)
since you mention you tested it from a vm and no problems there: is there anything installed and running on your pi (other than the octopi standards) which is not active in the vm? (This is a very vage idea of something kicking OctoPrint out of access to the serial )
Yeah, the logs are not big help but for the sake of completeness I added them.
what does dmesg report (called immediately after the havoc and only the last few lines are of interest but I think you can tell that apart)
-> I will add that EOD because currently I am printing via the VM
since you mention you tested it from a vm and no problems there: is there anything installed and running on your pi (other than the octopi standards) which is not active in the vm? (This is a very vage idea of something kicking OctoPrint out of access to the serial )
-> Well the VM has more plugins as the Pi. I "reconstructed" my Octoprint envoirment from the PI and added some addtional plugins for testing
Apologies @planetar for not having all answers at hand, I will update as soon I could recreate the error and read the dmesg
I found the problem. Apperently the buck converter was delivering the power but tend to drop the voltage underload.... I did some tests on the weekend ..
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