When I hit up on the controls to move up actually moves the router down and down actually moves it up - why would this happen?
When you go through setup, you check the direction of the axes. You say yes or no to the direction.
You can change these settings by
Going into the Grbl Settings and make the change.
It would be the $3 setting If you Enter $3=4, that should reverse the Z only.
Xcarve GRBL settings - X-Carve - Inventables Community Forum
That would only work if the seeing was already zero. Otherwise you affect X and Y as well. To change the Z, you must first determine the current $3 value. If it’s 0-3, add 4 to it. If it’s 4-7, subtract 4.
That’s why I included the link below…