Dot Peen Marking

I searched for a way to impliment dot peen marking for engraving part numbers on my plasma table, I understand that the tool paths are done on the cam side but is there a way to control the start and stop of the tip, I have the engraver on a pneumatic linear actuator using a 5/2 valve for the scribe arm up and down of the engraver and a separate valve for the scribe on 

Have you had a look here:

linuxcnc.org/docs/devel/html/plasma/qtpl...c.html#plasma:scribe

If that doesn’t completely help, please let us know what questions you still have.