Runoff 3.3V on expansion socket

[bigsub]

Hi to all, I bought a pcb relay board as this attached. It runs ok, but I'd like to runoff the psu (so the relais) at end of a print job or remotely instead of by a hand switch on 3.3V wire.
I check with M81 but it seems that the only way to runoff the relais is putting off the 3.3V. Is there a way, via gcode, to cut 3.3V on expansion socket?
Anyway, I don't know why this board wants also the ps_on wire.

Any ideas?

[dc42]

My impression is that you have purchased one of the few relay boards that doesn't have optically isolated inputs; but I can't be certain from the photos you have posted. Please provide a link to the datasheet or seller's page for that relay module.

[bigsub]

@dc42 said in Runoff 3.3V on expansion socket:

My impression is that you have purchased one of the few relay boards that doesn't have optically isolated inputs; but I can't be certain form the photos you have posted. Please provide a link to the datasheet or seller's page for that relay module.

Hello, I finally choosed a simple relay board optically isolated as written in other posts here.

BTW, this is the link of the object in aliexpress

https://it.aliexpress.com/item/32974992635.html?spm=a2g0s.9042311.0.0.27424c4dYNXVMk