Hypertherm hsd130 interface

I ended up using a reed switch. Worked great.
Ran a few cuts in plasmac and the arc volts read as they should.
No apparent problems with the hf start. 
Tommy, thanks for the guidance and helping me safely work through my confusion.

Do you think using a reed switch would have much of an effect on pierce delay?

bentiggin wrote:

Do you think using a reed switch would have much of an effect on pierce delay?

No, they are pretty fast but i can not recall the exact Ton/Toff time, it was 40 years ago when i started using them, but i am sure it is negligible.
You might have another issue, failing to trigger, so did you check that it does reliably trigger at lowest current setting?

I only tried at 45 amps. How low is worth testing? 

Whatever is the lowest you might use.
Last china one i had needed 3 turns to work reliably at 20A, and that was the lowest it could be set despite the knob being marked as 10A as well as showing 10A on the display. At 33A shown/set it would do 45A, and at 60A it would do 60A.

I tried a few cuts at 20 amps and got arc ok, but couldn't get any at 10 amps, which is fine, can't imagine needing 10 amps.
I did a fair bit of cutting at 45 amps and I did lose the arc ok signal in the middle of a cut. It was artsy text so I assume the feed was lowered automatically like it does for small holes. It only happened once, so it may be a fluke.

I have plasmac.arc-lost-delay set to .1. Should I try increasing that or is there a better solution?

I sure hope this hypertherms amp setting is more accurate than your china one, since I have no way of measuring actual amps.

I have the delay set to 0.2 or 0.3 always, depending on thickness, i would guess 80% of my machines are at 0.3.