Follow up, that may help somebody else following this thread. With this new plugin I was cutting a small circle .400 with 1/4EM, then moving off 5" in Y to change the part then repeating many times (x100), I found I was losing location in Y. Knowing Galil pretty well I
carefully reviewed the Galil plugin log and saw no cause for the drift. I then recreated the arc program in DMC language and ran it in DMC smart terminal (ST), it did drift in Y although a factor of 10 less over the same number of cycles,
but still not right. Neither Mach or ST ever drifted in X, even when I made the 5" move in X. I think this proves what Steve originally suspected that I must have something mechanically wrong with my CNC. Over the weekend I took Y completely apart and
did find a point of slip, I am fixing that.
Thank you Steve! Any thoughts why the mechanical would cause a greater position loss in Mach3 than it would in ST... Hmmm as I write this I think the difference could be the motion profile dynamics are different in Mach3 than they are in ST, so it makes sense that the mechanical flaw would show it self differently. To show a flaw in ST you need to push the motion profile harder with more complex moves, this is why I did not originally see the problem. It is like a car with a mechanical flaw may not show when a Granny (ST) drives it, but will show when a race car (Mach) driver drives it. You can push ST harder with greater AC SP and more moves, you just have to do that in testing like this. I could have saved myself some time by pushing things harder in ST. I learned something here.
Also while I am redoing things I am changing the gear ratio of Y to match X. I advise somebody building a machine to do this because it makes it much easier to use ST to test (or use for production in a pinch) since you can not easily have a different pulses per inch in ST like you can in Mach3.
Matt