Ah, i only guessed you were inches by the small numbers Z-2 etc, you will need those made up to something like Z-100 or so.

Anyway, if the motion does NOT stop regardless of probe then there is a configuration issue somewhere.

I have had NO luck in reproducing a probe input using the keyboard etc, never could get that to work.

I would NOT bother with the CS_LABS M31 code yet - its more complex and harder to debug, it will NOT work unless you can get the motion to stop when the plate is grounded - that is rule No1 to fix. The code DOES work though as i use it all the time.

you have to have a real Hardware Input on the Controller, Simulation via keyboard will and can not work,
because the probing is running on the Controller.

Emulation does work with the parallel port, but most, if not all, motion controllers do not support keyboard emulation of inputs.

Thanks guys, will give it a try tomorrow. But anyway....why is G31 Z-4 moving way further than -4 ?

If you are metric then -4 might not even be enough to make it work?

try -100

but use the actual touch-plate not a key or mouse

Just a correction, i gave some misinformation earlier.

Do NOT use G28.1 - it will NOT work in your case, G28.1 is a homing/ref move and uses a normal input NOT the probe input.

Stick with G31 as that is the proper one and uses the probe/digitise input.

I was at the machine and gave G31 a try.
Z axis stops either on touch or latest after the given Z value with: G1 G31 Z-4.
With G31 Z-4 it stops at touch, but overrides Z-4 in this case.
It does not stop at all with G1 Z-4.

Just want to mention the last case, as in many examples from the net it is described such.(Maybe works with parallel port I/O, but I guess most will use Win7 or 10)

Thanks a lot for you help guys !!!!