CNC Interface and Torch Voltage Capture

[EmptyNester]

I've been working on the software over time and spent this weekend getting the hardware prototype done.

My goal was to have enough to allow me to test my table without THC functionality. I believe I'm there. It works on the bench, I just need to try it on the CNC table. (Currently focusing on getting all SheetCam and Mach configured properly so I can try to cut.)

I figured that I'd build the prototype cheap and easy. If/when it works well, I I'll do a clean build. I didn't want to spend a lot of time in case I had to rework anything.

So I could test the software, I wired the buttons before I had an enclosure. I make the wires long, so now its a bit of a rats nest.

To prevent any issues with ground loops, I wanted to put the electronics in an insulated box. Project boxes are expensive and I didn't feel like making a wood enclosure for it. So I went to Walmart and bought a cheap plastic food container. They didn't have much to choose from and I ended up having to get one with a vent in the middle. (The hole in the lid.)



The single push button on the left is to set the mode (disabled, run, manual torch moves). I haven't wired it yet because its a late addition.

The two red buttons are for voltage up and voltage down. They will also allow moving up and down through the menuing system.

The black buttons on the right are for the menuing system and are "Menu/Select" and "Cancel".

I looked at a number of different prototype boards. I ended up using one that is made for the Mega board. I put the voltage divider on the board (it includes a filter cap and zener diodes for overvoltage protection). You can see the resistors left of center on the board.

You can see the corner of the relay board on the right behind the Mega board. This is for the plasma trigger.

I haven't finished the voltage sensing circuit. I need to add the amp/filter. I have an op amp circuit that filters off anything over 100 hz. Hopefully that will help with noise.



The box has a DB-9 at each side. One goes to the CNC port and the other goes to the motor control. Since I knew I'd have to work on it, all the wiring connects to the board with plugs that go on header pins.

I had to change the LCD display mounting. It usually mounts on top of the Mega board, but I wanted the proto board there. So, I made a couple "extension cords" that all them to be separated.