reduce z height travel at start of code

I have just purchased a Genmitsu Vice for my 3020 plus, but now i am struggling with Z height, at the start of every program the head moves up and hits the Z limit switch, i need to reduce the amount of vertical travel at the start of the code
i can google it, but was hoping someone of here would help

Thanks for any help

Hi -The first move is not a programmed move, it is a move by the controller. Its either moving to the set safe height or to a clearance height. Depends on what CAD and CAM you are using. So what CAD CAM are u using? Peter