Best posts made by sinole

https://docs.duet3d.com/User_manual/Reference/Gcodes#m591-configure-filament-sensing
depending on type of filament sensor you are using things change . If its a switch, you need to know if it is normally open or closed that determines whether you have filament or you don't. if you want it to detect and pause during print.
for normally open switch
M591 P1 C"e0stop" S1 D0 ; filament sensing during print
if that didnt work just try P2
you can also setup sensor to detect filament and auto load in new firmware, which you need to make trigger file for. i suggest you get this covered first.

@nightowl999 When you use a massive ups the power doesn't drop so duet doesn't detect anything until ups is dead at that point what is the point of using ups. but ups can detect the powerloss and trigger the board on a pin.

@nightowl999 I just skimmed your thread. CNC machine is very power hungry I assume. my application is 3d printer, a small china ups is pretty massive for a BTT or MKS. i think you need a 5v ups for duet board.
the config is pretty well laid out in wiki
https://docs.duet3d.com/User_manual/Reference/Gcodes#m911-configure-auto-save-on-loss-of-power

"For Duet + SBC, a solid external 5V supply is recommended for the Duet + SBC for this feature to work. When power to the Duet + SBC is cut, the SBC may turn off before the Duet can inform the SBC about the content of resurrect.g, or the SBC may lose power while it's trying to write the content of resurrect.g to the microSD card. An external 5V buck regulator may be sufficient to keep a Duet 3 Mini 5+ and SBC on long enough. For Duet 3 MB6HC, the on-board 5V regulator might not endure long enough for resurrect.g to be written to persistent storage if the Duet powers an SBC as well. Hence we recommend using an external 5V PSU if this feature is configured. "

@nightowl999 well looks like if you have a ups module you can manage the power recovery very well even without M911. in trigger file you can pause the printer or cnc with G25 and it makes sys/resurrect.g
after that you can just recover with m916. I will write guide if it works, I think you can use it. those ups are very cheap.

@nightowl999 not really but it should be a misprint, i should actually try that.

@phaedrux v3.4.1 I think. I copy and paste them inside config, I don't like 2 config files. I'm OCD like that lol. i stumbled on M570 Im about to test some stuff.

@fcwilt thanks, so if the move is long it wont trigger on time to save the print.