Yup, I really like being able to walk around the machine without cables, and jog while I can see what the tool tip is doing, so I'm loving having the wireless MPG working.
Good catch on the Z axis. I missed that looking at the specs. I've been doing a bunch of work on fixtures and alignment the last month or so, once I realized by X/Z axis was bowed to the back of the table by about 0.020" and starting tuning things up to correct it. Two-sided machining was giving me a horrible time until I figured out what was wrong.
I wonder what Mach 4 and the smoothstepper do with machine units in mm, but steppers driving in imperial? Rounding to nearest microstep I would imagine? I would guess that would show up in physical measurements on the machine though, and not in the DRO on mach. Also, at the bottom I would imagine the machine has to count steps anyway. Otherwise relative motions by amounts that are not integral steps would start causing drift as rounding errors accumulate.
I have been using a metric Haimer taster to do a lot of my alignment checking against known flat surfaces. The Z axis, I think, has been remarkably consistent with being able to step by 0.01mm, 0.1mm and 1mm accurately, but I have not watched it super closely with this in mind. Stepping on the X/Y axis though by 1mm seems to give me a shade over 1mm in step. It always returns to 0 where I expect it to if I step away 3 or 4mm and step back to 0, at least using the keyboard jog.
When I get a chance, probably next weekend, I'll try doing some testing with the jog wheel on different settings in imperial and metric mode.
Will be interested to hear if you get any information in the meantime. Right now I just set the jog to 0.1mm, and spin the wheel a bit more. That seems to keep the DRO readout in increments of 0.1mm without and drift.
I have also noticed a difference when stepping up to the soft limits. The keyboard jog will run right up to 0. The wheel jog will not run to zero sometimes in continuous mode. It gets close, but not quite, and then says that a further step would drive past the limit. This is a bit annoying when I actually do want to move the head to one of the limits.