Mach3 Serial Port Plugin Container
This is an ongoing development. I've been working on an Arduino-based Torch Height Controller for a while. I currently have the hardware design stable and functional and mostly complete THC code. While there is a Windows-based app to control the THC - I've recently been working on a Mach Plugin.
6 Axis Mach3 Breakout Board USB interface IO extension CNC Engraving Machine. Comunicate with mach3 controller card by RS232. Packaging Details.
This is my first Mach Plugin. I have initial functionality working.
The plug-in communicates with the THC over a user configurable COM port. It allows setting the THC operating mode, setting the target cutting voltage and monitoring the operation. The plugin spawns a new thread for handling the serial port communications. Cdc driver for mtk 6582 rom. It also gives the ability to set Mach's 'THC Mode' to ON when starting.
(There is a configuration option to stop and restart the serial thread - that doesn't work yet. If you change the serial port you have to stop and restart Mach.) Software source code, hardware design information and a user guide is available on github under the 'regeg/ArduinoTHC' project. Video of the test cuts with steel on a steep incline can be seen at: All of the history of the development and lots of voltage captures of cutting are on the Plasma forum at the Everlast Generators site. I'd really like to get people building the THC and contributing to the project.
I've been in a very similar situation. Designed a microcontroller based board for marking hole centres. It's a closed loop control that monitors when the torch has fired or monitors current level (user selectable). Then a user adjustable delay to determine the size of the crater in the top of the metal.
So even if your cut current is set at 100 amps, the hole marking can be done at 15 amps. Works absolutely great and I have complete control over the size of the tiny divot in the top of the metal. Even post cut airflow on or off makes no difference because this is a closed loop control monitoring what the torch is doing. I was looking at turning it into a product but basically got no interest either, so now just use it for myself (quite often). Wouldn't want to be without it.
Finally, after so much time spent in thinking, I’ve bought a Chinese CNC. I’ve choosed the model “3020T USB” from CNCEST manufacturer because it have a USB port; other cnc’s need a pc with parallel port and I have no pc with it! I’ve just a MacBook PRO with Windoze7 running on Parallelsit must work! I’ve bought it from ebay seller “top5zoom” that shipped it from Germany via DHL for free. The machine arrived into two big boxes.
The packaging was made very well with 5cm soft plastic foam that protect and stabilize the machine into the box. The total weight of the two parcels was 35kg!!! The machine is very noisy during operation. I’ve enclosed it in thick foam boards to reduce it. The first thing to do after unboxing was assemble it.
Just screw in 4 power supply connectors. Simple and easy. The second was check the ball screws,all 3 axes are moved on ball screw, and greas it with heavy aeronautical grease “Anderol” from US Army surplus. Probably standard grease will do the job but I’ve preferred my military grease. At first I’ve found that the VFD controllor had a corrupted configuration.
Following the first part of this post that I’ve found on a, thanks to user “gmungas”, I could have it running well. This is the VFD controller. 
The post: 'I finally figured out the VFD and software settings for my 1.5 kW, 110Vac, 400Hz Spindle with the PRT-E1500W VFD in order to run the spindle either in manual mode or with through the PC. Here's the procedure I used. (Note I didn't change the 220V setting to 110V in the VFD since there isn't a mechanism for generating higher voltage than the VFD supply and it doesn't appear to be necessary, but this should be vetted by another party (CHIMERA1960?) prior to long duration running).