Most plasma cutters will turn off if the arc current drops too low. Making a pierce and sitting there (pierce delay too long) will result in it shutting off. The torch just senses the current flow (not a ground detection) and if you don't have a good workclamp connection to the material (i.e workclamp clipped TO the material). I don't know anything about the plasma230. It looks to be a HF start unit so it should work for automated cutting.
Where are you setting the pierce delay? What are you using to generate the G-code? There is a value in MACH called THC Delay. It causes MACH to ignore any signals (strange or not) from the THC after a pierce. It's defaulted to 1 sec. Increasing that may help.
Tip Volts = Arc Volts = Gap Volts
ARC OK = Arc Xfr = OK to Move
Things to remember:
1. Workclamp is NOT ground (until you clip it to something that is already grounded.
2. Your table needs to be grounded locally with a ground rod(s)
3. Cutting with a plasma unit that has no available cut chart requires you do a series of test cuts and take notes. The first number to determine is the "cut gap" (how far above the metal you hover as you cut)
4. You can't use drag tips for automated cutting
5. There are a lot of parameters to master to get good cuts.
6. There is no "Easy Button"
You can make that plasma work it's just going to be a lot more work to get all the settings worked out.