After a day of googling, I havent been able to find an instance where someone has implimented automatic torch height control with the Marlin firmware.Basics of Torch Height Control. THC is used with cnc plamsa cutters to read the voltage of the arc being used by the plasma cutter to fluctuate the Z height continuously throughout the cut to deal with the warping of the material caused by the heat. This is done on the fly every couple of milimeters at a minimum. Maintaining consistent voltage throughout the cut will create a cleaner and more professional cut.
There are a couple of THC units available. For the most part, they have an start cut relay, ARC OK, Z up and Z down outputs. For inputs they have start cut and voltage input from plasma cutter. These units can be purchased or built using an arduino.
The easiest way to have THC is using Mach3 and standalone THC, but I havent found a way to use a Rambo with it.
As far as using repetier with THC, the only way Ive found to make that work is the Babystepping function.
If anyone has some insight into this or advise, Im all ears. Unfortunately Im not skilled enough with arduinos to even know where to begin to make this work. In my searches Ive found that there are hundreds if not thousands of people who would love to be able to make this work using ramps, rambo, etc. Figuring out a way to merge either repetier with THC or an arduino with Mach3 cuts the cost of a solid cnc plasma cutter down to prices that any hobbyist could get down on.