UPS cuts power to the outlets when power returns

Hello everyone, I'm new to OMV and just starting out with Linux.

I’ve installed OMV 7 on a Ugreen 2800, connected my APC UPS PRO BR650MI via USB cable, installed the openmediavault-nut plugin version 7.0.8-1, and the NAS auto-shutdown feature after X seconds of UPS battery takeover works correctly.

The issue is that when power returns the UPS cuts power to the outlets and all devices connected to the NAS shut down.

I’ve left the plugin settings at their defaults:

• driver = usbhid-ups
• port = auto

Is there any additional parameter I should add to prevent the UPS from shutting off when I restart the NAS?

Thanks everyone.

The router is also connected to the UPS. What happens is that when power returns, the UPS turns off its outlets, and both the NAS and the router obviously shut down abruptly. But this only happens if NUT had previously shut down the NAS via OMV. It's very strange—I thought there might be some parameter to pass to NUT...

I tried to comment the lline

# POWERDOWNFLAG /etc/killpower

in /etc/nut/upsmon.conf

and it worked! UPS do not shut down when power returns.

The problem is that the file is autogenerated by OMV and there is apparently no way to give this directive on the nut plugin gui. This means that i need to manually edit upsmon.conf every time OMV touches it.

Thank you votdev.

i am a complete beginner so using your hint I asked to AI a step by step procedure, is it correct? I would like to be pretty sure i won't damage anything...

ssh root@indirizzo-ip-omv
omv-env set -- OMV_NUT_UPSMON_POWERDOWNFLAG "/dev/null"
omv-env get OMV_NUT_UPSMON_POWERDOWNFLAG
monit restart omv-engined
omv-salt stage run prepare
omv-salt deploy run nut
cat /etc/nut/upsmon.conf | grep POWERDOWNFLAG

Quote from votdev

Looks ok. But i don't know how the POWERDOWNFLAG is interpreted/used by NUT; if it checks for the existence of a file /dev/null isn't a good choice.

I have really no idea, the AI says that 'This is the correct technical solution because /dev/null is a special device that 'swallows' everything, so the flag file is never actually created, preventing the system from ordering the UPS shutdown.'