XHC-HB04, zero current axis from "=0" button, and axis selector

No P0 just applies to whatever coordinate system is currently active. So if G54 is active it is applied same as using P1. But if G57 is active it would be the same as using P4. Because it is variably applied dependent on the current coordinate system, it might be useful for a button command like you are setting up. It lets you set any coordinate system offset rather than just one.

interesting, that could prove very useful. Thanks!

~Travis