@pro3d
I add code to my slicer Simplify 3d
to start the ATX power supply

my code in Start scripts
M80; Start ATX
G4 S5 ;Yield 5 sec before continue
M104 S[extruder0_temperature] ;Preheat Extruder
M190 S[bed0_temperature] ;Wait for bed to heat
M140 S[extruder0_temperature] ;Wait for Extruder

I should properly not use the M104 command but its fine..
heats up the nose but I will properly move it to after 😄

The Myyy[xxxxxX_xxxxxxx] tells simplify3D to ignore its own inserted commands.
so it will not insert them before you start scripts