Jazz if its possible to get the driver encoder position back into Mach3 or even use the build in soft DRO's in mach3 like eddy suggested along with the sensor output it would create some very useful possibilities to toy with like e.g. a contactless edgefinder for setting work-offsets. I might be totally wrong but my gut feel is that the mach3 soft DRO's does not always know where the machine actually is in real-time while moving if you use a controller that does buffering etc ?