First time ever had this issue come up. Milling a pocket that is round. Cutting just fine and then the cut just stops cutting for no reason . On the mach3 screen it says emergency mode active,external e-stop requested . Can't restart program . Have to reset and start program from start and then the program runs the whole program all the way through. Sometime when the program runs all the way thru,then I run the same program again and it stops the same as describe above. Not sure what to look for what is wrong.
 Had issues when I added a led light on the mach3 screen for the probe pickup . The light for the z height pickup would not light. So I switched the wire around with the e-stop and then the z height pickup worked.Dont know why this worked either .
   Thanks Dan