First sparks - Thanks everyone!

Last night I made my first cuts on my "home handyman" level plasma CNC table. It's still a messy experiment, but it's getting there. Thanks to everyone that helped me get to this point!

Here's a high level look at the build for the curious:

• Raspberry Pi 4 with PREEMPT_RT kernel
• LinuxCNC 2.9 + QtPlasmaC
• Mesa 7i96S
• THCAD-10 
• Proma voltage divider
• Reed switch for ARC_OK signal
• 24V Meanwell motor power supply
• 5V Meanwell logic power supply
• Ohmic initial height sensing circuit
• Shielded P-80 machine torch
• 40 amp plasma cutter with HF Pilot Arc
• Rails from OpenBuilds V-slot
• 3D printed plates
• Magnetic torch breakaway
• Belt-and-pinion X and Y axis drive
• Acme screw Z axis
  
  Once I can cut reliably I'll use it to make it's own aluminum plates. I also plan to swap the Raspberry Pi for an Odroid N2+ once rodw releases support for the PREEMPT_RT kernel.

Great work Alan. It's always good to see another plasma table come to life. And amazing that a Pi is doing the job for you.
Good idea to use the proma in a HF environment. Is that read by the THCAD?
a 48 V power supply might give better motor performance if your driver's can handle it. See how the cut quality is on corners and keep it in mind.

Unfortunately, the N2+ is on the back burner as it's in Leonid's hands. He says:
The state of my repository on github is not complete for building additional packages. After my last email, I decided to check my current work and push it to my repository, but I found an error in the algorithm. And now I'm making changes. I'll let you know when it's ready.

Thanks Rob. Proma specifically calls out in the voltage divider documentation that it can be connected after the HF coil (ie. directly to the external torch electrode). So far it works perfectly.

I realize that this breaks one of the plasma cutter wiring commandments, but I couldn't resist giving it a try. If it fails to fry something I think it will make adding a THC more accessible to folks that have cheapo plasma cutters and that are averse to digging around in the cutters internals. Time will tell...