I have a CR-10 and an Ender 3. Both have worked fine for months with latest Octoprints.
I recently added AC bed heaters. They really heat up fast and high and they draw a lot of power. I've printed a number of small prints with them. I've also built styrofoam enclosures for both of them but they only get up to about 45 degrees C inside. (The electronics are in the enclosures but 45 should be no problem.
The other day I started a long print on each printer and during the night both failed with the exact same error at the exact same time. This is the error from the log.
019-05-29 21:36:36,295 - octoprint.util.comm - ERROR - Unexpected error while reading from serial port Traceback (most recent call last): File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 2605, in _readline ret = self._serial.readline() File "/home/pi/oprint/local/lib/python2.7/site-packages/octoprint/util/comm.py", line 4681, in readline c = self.read(1) File "/home/pi/oprint/local/lib/python2.7/site-packages/serial/serialposix.py", line 501, in read 'device reports readiness to read but returned no data ' SerialException: device reports readiness to read but returned no data (device disconnected or multiple access on port?) 2019-05-29 21:36:36,328 - octoprint.util.comm - ERROR - Please see https://faq.octoprint.org/serialerror for possible reasons of this. 2019-05-29 21:36:36,357 - octoprint.util.comm - INFO - Changing monitoring state from "Printing" to "Offline (Error: SerialException: 'device reports readiness to read but returned no data (device disconnected or multiple access on port?)' @ comm.py:_readline:2605)" 2019-05-29 21:36:36,480 - octoprint.plugins.DisplayLayerProgress - INFO - Printing stopped. Detailed progress stopped.
I'm guessing the printers rebooted but I don't know how to find out if they did. It is not like the printers have logs. Is there some way to monitor a printer's health and log it in octoprint?
This has happened again to each printer but not at the same time like the first incident.
The only thing I can think of that is in common is the 110 VAC mains coming into the printers. This is in an old garage that probably has crappy wiring.
So I bought a good 500W battery-backup UPS (uninterruptible power supply). I only plugged the printers and raspis into the UPS and left everything else, including the bed heaters, plugged into the wall.
I started prints on both printers and within 10 minutes one got the error again. I'm returning the UPS.
I know this is probably not an octoprint problem or any other software but I'm desperate since I can't print and my job depends on it.
Any ideas would be greatly appreciated.