I’m running Mach4 Hobby on the ArcProPlasma-v5 screenset and a HiCON 7866 controller on a Premier Plasma table.

My issue is with the M5 macro / torch off behavior.

When I issue M3, the “Torch On” LED lights and the torch fires normally.
When I issue M5, the 'torch on' LED stays on and the torch continues to fire until the plasma times out (hole gets too big).

I checked the HiCON relay output (RL1 on p14 Output 5, mapped to Spindle On in Mach4):

Idle (torch off): ~3 MΩ (open)

After M3: ~0.06 Ω (closed)

After M5: still ~0.06 Ω (relay never opens)

So after the M5 macro in MDI, the HiCON relay doesn’t release.
Re-mapping to Spindle Fwd didn’t help.

HiCON 7866 - firmware 2.50.83.
Mach 4 Hobby - version 4.2.0.5036 (build 5036)

Why is my M5 macro not releasing the spindle  and letting the relay restore to a open state?