I don't see how any machine can "remember" where it is/was unless it carefully writes something to ROM and then homes itself at start up next time. My Eztrak is supposed to do it and usually it does but it ain't perfect at doing it and it is set to write turn off postion to internal cache file.
As powerful as automotive computers are anymore, you have to tell an automotive computer to start counting over each time the crank rotates - and they are only counting to 3 or 4 depending on the engine. I don't see how a CNC would be any more conducive to "saving" position unless it were programmed to do so - even so, I"d still check cuz I don't trust them.
At start-up, there is so much redundancy that it is damn near impossible for the things to forget where they are or what they're supposed to do next - even if they lose a sensor, they have "limp modes" built in so the thing will at least run.
Haven't seen that level of redundancy support outside of aircraft or aerospace - for sure NOT in some of the "professional" industrial controllers that I've seen.  |