Z probe issues - moving up instead of down

Hello everyone, I am getting stumped on an issue I am having. I have a printnc running grblhal with gsender 1.5.6. I can jog, move and home my machine without any issues. I have been manually setting my 0 point to date, but now I have started to try and use my auto zero touchplate with tool changing in mind.

The problem I am having though, is when I go to probe z, the z axis moves approx. 2 mm up, then a further 10mm up instead of down towards the probe. I have tried to go through all the setting to see if I have missed something, but I am drawing a blank. I have power cycled everything, uninstalled and re-installed gsender, but nothing seems to correct the issue.

Is there anything I may be missing or not thinking of?

@Brink01 Welcome to the group, Dan.

What controller are you running for your printnc CNC?

Hi gwilki,

It’s one of the generic red Mach 3 boards that came with my stepper motor kit. I have flashed it to grblhal via st-link.