Hi Craig,
I've checked very carefully for any A axis moves in screen load and PLC and there are none.
I do have to reference the axes on startup. Is that what you mean?
I've also checked that A axis is not enabled in homing or limits in Mach4 settings and in ESS settings.
Steve I just tried setting the home in place for the A axis, and the error is still there on startup!
This is a stubborn little bug!
Thanks very much for the suggestions so far
Leo