Simplify3D User Forum

Lets say I just pressed the Home Z button.
In my case my Z is homed at its MAX height 150mm

While its still in the homing process. IF I press any one of the buttons to do a move say 100mm Downward.
the DRO will instantly display -100.00 and once the homing is done attempt to goto -100 ie should have been a move to 50
so head crash is imminent.

IF I wait till the homing is complete. I get -50 on the DRO and the head moved to the 50 position.
I have reproduced this many many times.
-S

O/S is MAC

Sounds like your homing endstop directions are incorrect. You probably have the Z-endstop direction set to min instead of max.

Also, any head crashes should be protected by the firmware. The firmware already implements mechanical endstops as well as software endstops to protect against over travel. If you are able to crash the head then your firmware is not setup correctly.