Re: [CAD_CAM_EDM_DRO] servo controller

elite_toolmfg wrote:

>I'm looking to upgrade a cnc knee mill that I have from an Anilam
>Crusader M control to PC based. All I need is to control the motors,
>I don't need a cad/cam program. I want to feed it g-code and it
>moves. I also need tool length offsets. My servos have tachometers
>and the table has linear scales. I would like feed back to the pc
>from these scales to assure proper positioning. Machine works --
>limited memory and poor interpretation of g-code. Any suggestions to
>a kit or something? The servos are good and I think I'd like to keep
>them since they seem to be the most expensive part of a retrofit.
>I've been told that I just need some geckos and a pc control program,
>true? I'm a pretty good DIY'er but not a know it all. Thanks
>
>

The Gecko servo drives will drive servo motors, but they do not get the
position back
to the computer.

I have a servo motion system that should work, assuming the linear
scales don't need
interpolation to get sufficient resolution, and put out signals that go
from +5 to ground.
If they have some other interface, it can probably be converted with
only a little work.

What make servo amps do you have in there? Do they take +/- 10 V signals?

My hardware is supported by EMC, which has a pretty good G-code
interpreter, and the
price is right ($0). I have used tool length and cutter radius
compensation quite a bit with
it. The Gecko and software step pulse generation has some limits if the
encoder resolution
is high, at least with some software. A true servo system gets rid of
this limitation, since
there are no step pulses. The motion system sends velocity commands to
the servo amps.

See http://jelinux.pico-systems.com/PPMC.html for more info on this.

Jon