useing  mach 2 to control plasma table , just hooked up z axis. Can
anyone tell me if you can manual contol the z up and down while a
code is running.. if so how? setting up g code with sheet cam if
that matters...

I am sure I saw the same question answred a while back, I will do a search and post a link if I find it.
Hood

Heres the thread I was thinking of, not read it again so it might not be relevant but have a look.
Hood

http://www.artsoftcontrols.com/forum/index.php?topic=2656.0