Originally Posted by
Brian L
The machine should home to the limit switches and reset the DRO to zero. Then there is a parameter in the machine for how far down the machine needs to move to do a tool change, that can change if you move things around and change the position of the zero point on the Z axis encoder. I can't fathom how your machine is changing Z0 to be over 9" in the Z minus direction. Did you check your G54 position offsets and make sure you don't have a huge Z offset in there?
My machine is a knee mill, so I'm not as up on the tool changer versions but there must be something set incorrectly.