It all depends on what you are using, is it the parallel port or an external controller?
What output does the MPG have?
Encoders are meant for inputting encoders to Mach so that they display in the Encoder DROs. they are only for information and user functions, Mach does not directly act on them. As an example I have a height setter for setting up my tool height offsets. I use the encoder input in Mach to feed the linear scale of the height checker, that way I can enter the height offsets into Machs tool table direct from the tool setter.
MPG settings are meant for MPG, ie encoders that are meant to control manual motion of an axis.
Hood