Ender 3 S1 Pro loses serial connection, stops mid-print

What is the problem?

Occasionally during longer prints the serial connection simply dies and the print stops.

What did you already try to solve it?

Replaced Raspberry Pi 4 power supply with a reliable brand (Canakit). Replaced USB cable with a short 6" cable. Made sure Pi is clear of other electronics and wires. Reinstalled Octoprint from scratch and have no plugins installed. Timelapse is disabled.

Have you tried running in safe mode?

Not yet. I'm reluctant to try safe mode because the problem is intermittent and I'm not even sure Octoprint is at fault here.

Did running in safe mode solve the problem?


Systeminfo Bundle

octoprint-systeminfo-20230831152136.zip (90.7 KB)

2023-08-31 12:33:01,934 - octoprint.util.comm - ERROR - Unexpected error while reading from serial port
Traceback (most recent call last):
  File "/home/pi/oprint/lib/python3.9/site-packages/octoprint/util/comm.py", line 4081, in _readline
    ret = self._serial.readline()
  File "/home/pi/oprint/lib/python3.9/site-packages/octoprint/util/comm.py", line 6832, in readline
    c = self.read(1)
  File "/home/pi/oprint/lib/python3.9/site-packages/serial/serialposix.py", line 595, in read
    raise SerialException(
serial.serialutil.SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?)

Additional information about your setup

OctoPrint version: 1.9.2
Printer: Ender 3 S1 Pro
Firmware: GitHub - mriscoc/Ender3V2S1: This is optimized firmware for Ender3 V2/S1 3D printers.

Searching through the forums it seems this is a pretty common issue. Octoprint gurus who have gone through this before - what is the most common cause?

It's super disappointing to get 22 hours into a 24 hour print and wake up to this:

Screenshot 2023-08-31 101603

Will loading the gcode file to SDCard for long running prints like this make it more reliable?

You.need to enable serial debugging and restart octoprint, then run a long print to capture what is happening

Ok, next time I have a long print I will flip this on. Was hoping maybe others with my printer had seen this before and knew about an easy fix.

On another note - can I simply bypass this problem altogether by copying the file to the SD card? I know copying over a serial connection isn't ideal but I'm willing to copy on my computer and carry the card to the printer if it means rock-solid reliable prints.

Upload to SD in OctoPrint uses the same serial connection as printing from OctoPrint so if the serial connection is being flaky, this method may have the same problem. It is also very slow.

Sneaker-net (i.e. physically moving the SD card) will be more reliable and faster. "rock-solid reliable" remains to be seen :sweat_smile:

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.