Hello again BR549:

I will explain about my M5 macro, but I have to do a job with the Mill, and install the components for a customer in another city.

Hopefully, I can learn a little more about Mach3 and macros, of which I still understand only the minimal basics. To answer your question, a description of how I built the retro-fit, and what has been done is in order.

Looking back, I now feel my Mill retro-fit project was short-circuited by adding in so much I/O i.e., Cubloc PLC and Modbus. It is easy to get enamored by having almost unlimited I/O, when only the basic machine control is actually necessary. It is very possible a partial re-wire would make things better.

Simpler is better, as they say.

I will get back to this post in a few days.

Regards
John