Hi,
not sure about Mach3. With Mach4 you can only have one motion controller but you may have more input boards. You could for instance have your PoKeys
as your motion controller and then have ANOTHER one as an input board. In fact PoKeys development history is exactly that, their boards all started off as data
collection/communication boards. Only later did they morph into CNC controllers.
You might think PoKeys is an expensive solution to data collection, its not....in fact PoKeys enjoy a good reputation for value for money.
One other way to get more input is with Modbus. Modbus would work equally well with Mach3 or Mach4. It will require a processor to 'assemble the data'
into Modbus format. Peter Homman of Homman Designs in Austrailia and long time contributor on the forum will probably have some good solutions.
You could also use serial input. I have not heard of any boards that work off the shelf, I think you would have to roll your own, probably cheap enough but potentially
very time consuming.
Anyway the 57 PoKeys have got swags of inputs/outputs, are you in any danger of running out?
Craig