Mach 3 Tool Height Setter

Hello all,

I have a CNCRouterparts or Avid CNC machine that we custom built to be 96"x96".

I am looking for a tool height setter that I can mount outside of the cutting zone to automatically set the z zero height. I have been unable to get everyone properly trained and they keep cutting into the bed. I want to upgrade the bed to be a vacuum plenum, but until I get a way for us to consistently set the Z to a safe height, I am afraid we will ruin the plenum that will take me a lot of work to complete.

I have done some searching but haven't found anything good for this. Any suggestions?

Also, if I did find some kind of limit switch setup for this, is there a way to tell the machine that if it has reached a certain point (maybe a missing router bit) it will error out to prevent crashing the Z-axis?

Thanks for any input!