My successful build of a LowRider V3 plasma rig was based on a “tried and true” plan in which the standard commonly used control boards (also common in 3-D printers) were ditched in favor of using a laptop that has LinuxCNC installed — and which communicates with both the LowRider and the plasma cutter through a breakout board sold by MESA electronics, via CAT5 cable, and accomplishes automatic torch height control (THC) by use of a second PCB also sold by MESA electronics. My entire build project is documented here:
There are many advantages to this approach. For example, LinuxCNC can be installed using a real time kernel, and using a certain graphical user interface called QTPlasmaC, that is specifically made for plasma cutting, and that accommodates torch high control. I posted lots of video.
I bought a used Acer laptop that boasts a touchscreen. I was able to get it for a very cheap price, buying used through eBay.
Regarding the advantages of a real time kernel, imagine something is going wrong and you need to stop cutting quickly— preferably without losing everything by shutting down all power. With a real time kernel, an emergency stop operates exactly like you would want it to. Compare this with how commonly used Marlin-based control boards act. They have a buffer that is filled with Gcode commands. When you try to pause or stop the job, it doesn’t stop right at that moment, but rather it has to finish all the commands that are already in the buffer. Those commands can result in a massive amount of cutting continuing after you told it that you wanted to pause or stop.