Gents

quick question on my milling machine i have home sensor on top of z-axis so at moment that is 0mm and then movement closer to bed is "x"+mm how to set 0mm to be fully down to bed and - max movement on top at home sensor ?

Hi,
that is normal, machine co-ord zero at the top of Z travel. When you drive the Z axis done the machine co-ords are negative.
When you get to the surface that you wish to machine zero the Z axis work co-ords. Then a negative Z will take you below the surface ie
cutting and positive Z takes you above the surface.

Craig