Hi,
if using Mach4 then this post belongs on the Mach4 General Discussion Board.....this board is about Mach3. No doubt Tweakie will shift it in due course.
Homing is a realtime procedure that is entirely enacted by the motion controller, not Mach4. When a Home switch activates the machine must respond imediately, or at least
within microseconds. The communication delays from the motion controller board TO Mach4 and then FROM Mach4 back through the motion control buffer would be a delay of
100 milliseconds or more, way, way too slow. Ergo the motion controller must do the job, and is one of the foundational realtime supports that a motion control must offer
to be useful.
Most motion controllers for Mach4, like an Ethernet SmoothStepper can read an encoder, but to my knowledge cannot trigger a Home event based on the output of an encoder.
Remember also that when a machine is Homed or Referenced it is the Machine Coordinates that are zeroed, and you cannot manipulate Machine Coordinates directly, in fact you
can ONLY set them as a Homing or Referencing operation, ie the motion controller alone can set the Machine Coordinates, and the motion controller requires Home switches.
I think Homes switches are in order for a simple and direct solution. I could forsee a couple of methods that might allow the use of linear scales to set Machine Coordinates, but
the complexity counts against them.
Craig