I did not think it was for transferring movement data.
It will not work for controlling the servo/stepper motors. There is a delay in the translators, and anyway those fieldbusses are not considered fast enough to do this. The only I can think of that is suitable for that is SERCOS, and then only using a SERCOS board in the PC.
But the communicators/gateways should work fine for PLC data like turning on/off suds pump(s), setting spindle speed, reading pendants, setting DRO's, talking to toolchangers and other non time critical funtions.
I might use PROFIBUS also for limit switches even if the realtime demands are higher. But then I know that bus inside out, and have the tools to verify looptimes and check everything thoroughly. I would not try that without.
If you need help in testing and/or verifying a PROFIBUS implementation for Mach3, call on me. I have the best tools available for that, and experience in using them.
Regards
Einar S