That sounds reasonable - I can see how that would work. The code wouldn't be that difficult. If I had known about it when I first set the machine up, I might even have done it! At the moment the drive enable signals come via the safety relay (which also switches the e-stop input to the IP/M and switches mains to the stepper PSU via a contactor - belt, braces and electric trouser hoist). Given that my ET6 should arrive in a few weeks, though, I don't fancy grubbing about in the control box to do the rewiring. I think it would also need X and A home switches in series to the same IP/M input so that the macro could home either axis by disabling the other while telling it to home the master/slave pair. More rewiring on my machine would be needed!

But thanks for the comment - I'll keep that one in the back of my mind.