Insert Gcode to take z0

Hi all and sorry for my bad English, I built a
floating head plasma cutting machine http://www.frs-cnc.com/foro1/viewtopic.php?f=2&t=1942 , I´m woking with sheetcam and try to insert in the code the Gcode for take a z0.

Could someone give me that code?

Possibly this issue was repeated in the forum but i can not find it … thank you very much in advance.

I don’t really understand what you want to do. Can you explain a bit more.