Z axis position

[Jipyaubin]

Hello,

I just bought a prusa i3 pro w, I mounted it as it should be, everything works fine.
My "home" position is all ok in manual but when I leave the printing of a part my software (easyprint3d) says that my machine is at z 0.03mm for my first layer but on the lcd I am at 5mm and in real I'm also 5mm from the bed ... Do you have any idea what's going on? Is there a z offset somewhere?

Thanks in advance