I've got a Bostomatic 14/40 here currently being controlled using a Fagor 8025M CNC, and am looking at the possibilities for retrofitting it a second time to utilize a PC-based solution, ideally using a solution like Mach3 or EMC2.
The biggest snag I have found so far is that the existing amplifier hardware uses +/- 10V DC input. Replacing the amplifiers and DC servos would likely push the cost of the retrofit out of what the budget for this project allows, so I need to come up with a solution that works with what is there.
It is a four axis mill, the usual XYZ and then a 3 jaw rotary parallel to X and controlled currently via W.
All four axis have that +/- 10v DC input, and use the standard ABZ type 5v encoders, I believe they are 625 lines per turn on 4 pitch ballscrews.
Spindle control isn't as much of an engineering problem, as it uses 0-10v DC reversing by relay- that amplifier also supports RS485, which I might try to use on it.
Ideally I would like to use an arduino or similar device to keep the servo loop closed in hardware instead of relying on the PC, making it so that the PC merely tells the machine where to move and how to get there, and the machine does the rest at a far higher response rate than having the PC control it directly would be able to.
My problem is what hardware can I use in between to get the required voltages for driving the amplifiers. The existing machine does have a 24v DC rail that I might be able to use a motor driver with, but I am not certain of the wiring of that.
Has anyone attempted a conversion like this before? What solutions would work, trying for a total project cost of less than $500. I do have enough programming experience to write the required micro-controller software for this to work.