Hot end idle stopping print

last night during a long print -9 hrs approx- my printer stopped with the message hot end idle. This has never happened to me before. I am wondering if there is some maintenance issue that I am not aware of or if one of the fans stopped and the machine went out on high temperature. When I shut off the machine and restarted on a new print there where no issues. My printer is a Creality CR10S Pro with a BL touch and an upgraded firmware. Ant thoughts or advice would be appreciated.

You say it was during a long print. I take it then that the print did not finish?

Within the firmware there is an option for idle detection. Simply put, it looks to see if the print head has moved recently. If it hasn’t, it turns off the heat.

It’s common to heat a hot end without moving it when changing a filament, a nozzle, cleaning a hot end, or levelling the bed. There is, however, a risk of damage if the heat is left on too long so this automatic shut-off exists to protect the equipment.

Of course, it should not go off during a print. The first thing that springs to mind is bad g-code. Printers will often abort a print if the gcode contains commands it considers invalid. This is to protect the printer from ramming the print head against the end-stops because it no longer knows where the print head is (because of bad g-code) and causing damage to belts, motors or alignment.

Have you printed that particular file before? If it printed successfully in the past, try re-loading it on the SD card, in case the file on the card is corrupted. Otherwise, try it again and see if it stops in the same place.

Thanks for the reply. The print was a trial run and I didn’t like it so deleted it. I have printed another couple of things since and it is working fine . Your suggestion of an invalid or corrupted g code command was likely the problem. Thanks again for your support.