Hey all,
  We have used the ESS with great success. Here comes the but... we have a machine that seems to take on a mind of its own. Not consistently, but seemingly random movement from the X axis on an OD grinding machine. We will be out of any axis movement, just minding our own business measuring the part, and when we look back at the screen, wouldn't you know, the X axis has moved in maybe .0003" or .004" . We are holding parts very close at 0 to .0002". It only occurs randomly 1 in 4 or 1 in 20 or 30 or whatever. I have changed the debounce numbers to 500 with no results. Any bright ideas on where to continue? We have replaced the computer, the keyboard and mouse. We have isolated the computer and separately the motor contact coils with isolation control transformers. The entire machine is isolated from the rest of the shop with a 20KVA stepdown transformer from 480V to 240V. We have another OD grinder 20 feet away with an exact duplicate of the screens and misc files and has no issues.  UPDATE: I just put another computer on the machine with XP and am getting the same results. RF noise? Ground loops? M code bug? Mach3 bug?
Tom

Not that I am of any help, but are the models of computers you changed the same?

Three different ones. One full size older xp, one new Walmart acer, and one HP.

Are you saying the DRO in Mach shows the axis moving when it shouldnt be?
Hood

Hood,
  Yes, not only the DRO but actual movement of the axis, which means scrapped parts.
Tom

Can you attach your xml  please.
If the DRO is showing movement then it is being commanded somehow and maybe there will be a clue in your xml.
Hood