PS-ON pins?

Sorry if it was already asked, but I honestly couldn't find it.

I'll be using server PSU, with 470W on 12V line and over 30W on 5V one. I decided to remove D1 from my RAMPS and power Arduino from 5V lines. And now I'm in doubt. Can Marlin use PS_ON pin on board? I have an LCD with SD card reader for it. Can I power Arduino from 5V_STB and connect PS_ON to, well, PS_ON? Or it wouldn't work and I should rather use standard 5V line and connect PS_ON of my PSU to normal switch?

I'll probably mount power plugs on both 5V and 5V_STB of my PSU, and put female goldpin on PS_ON, but that will only postpone decision a bit. This is something I'll have to decide before designing chassis, and we actually are in the process of designing it now.

See the wiki ramps 1.4 page

I did.

Quote

Many firmwares support pulling this pin low

That's all about firmware I see there. No word about Marlin in context of ps_on. If I'm missing something, please quote.

I'm confused. Do you want Marlin to turn on the power supply? Marlin can turn off the power supply at the end of a print. Or when something bad is detected. But you want Marlin to turn on the power supply?

5v is always on, so I hoped Marlin can turn 12v on and off as needed. That's what ps_on line is supposed to be for.

OK... If Marlin is alive and in control of things... What is the logic it will be using to decide if the +12 volts should be turned on?

Test if the Maga with the RAMPS is running on 5V standby with your power supply (that depends on the power supply). If yes, you can switch the 12V on and off with PS_ON.