m_c: Interesting insight there on your thought process - and entirely sensible.

I do, as a profession, deal with HMIs and ergonomics, but in a rather different field, but your points are very well made.

For me, I have an issue that I'm keeping my main computer 10ft away from the mill, and so I'm putting the functions to manage the interactive stuff (touching-off, etc) and the DROs onto the machine and enough to start/stop the program. Program management though, back at the computer. I've enough experience of tripping over hand-held pendant flying leads (replaced another USB plug last weekend when I sheared the connector by standing on the lead).

On the panel I've shifted the encoder to the right, with the DRO immediately to the left of it - so as not to obscure with my arm, and planning (once I get the IP65 chinese push-buttons delivered that I can get some accurate measurements to design with), push an Arduino with an Ethernet shield, use ModBus ethernet to hook this up (been playing with that - it's doable, and I had ethernet to the motion controller already - it makes sense to extend this to the machine).

I've contemplated touch-screens in the past, and kept an eye out for cheap ones (I am cheap) - I do worry though about heavily oiled fingertips with any interface (I'm am dirty).

Most of the stuff I've done on the starmill is an evolution on the previous attempts... for me I know I'll make mistakes, learn, and try again. It's a hobby :) One day I'll be happy, but that's a while-off!