Help auto tool zero not working

[dazp1976]

Thank you for responding, I tried using your code and the same thing happened. I am not understanding why the z axis is moving up instead of down to the material. When I click the Go to zero button,

When you say 'it goes back up to the starting point' is that your machine coordibate zero?.
Just something else to check. It could be working off your machine coordinates instead of your work coordinaes.
It's a long shot and odd but something to eliminate.