AVHC is not bring down and plasma is not ignition sometimes when pierce material,but the machine normal running and adjust height by hand.

If only reopening programe that AVHC resume normal cutting.
thanks to reply .

reed

Are you saying that sometimes the height control fails to go down to sense the material, and retract to a pierce height, and then fail to ignite? This could be a delay setting in the software depending on the distance in between cuts. But the fact reopening the program affects that is strange. Perhaps you could give me an estimate of the frequency of the problem, the solutions you have come up with to fix it, and the exact sequence in which the problem occurs.