Interact 412 with TNC 145 control

HELP!!!

Our machine has gone a bit funny and the spindle doesn't come to the right height for doING tool changes.

The Z home height is still perfect, I double checked by recalibrating using a tool with a known offset height.

the changer is coming in few millimeters high.

I know that there is a parameter that tells the machine the distance from the Z home but I don't know what it is or how to get there.

I'm meant to be milling a gearbox for a friend going to the Isle of Mann TT the day after tomorrow (Weds) so I am a little desperate to fix this quickly

James