Re: [CAD_CAM_EDM_DRO] conversion of old nc to new drives

On Friday 14 February 2003 13:06, doveknives@... wrote:

> I have an older Tree Journeyman two axis knee mill that was set up to take
> some sort of cassette reader using somesort of magnetic tape cassette

<snip>

> I would like however to see if there is anyway to conver this machine to
> operate off a PC and still use the factory installed x&y axis motors and
> encoders. Can anyone help me with advice on how to do this?
>
> Trusting HIM,
> Steve Rollert
> keenedgeknives.com
> doveknives.com

<snip>
I have one of those that won't complete initialization. I have similar plans
for later this spring (have to build shop first).

The cassette tape was very popular in the early 80s; I have no idea if it is
digital or analog.

I've done a little bit of investigation and have high hopes of using the
existing servos and power supplies. Might be able to use the amplifiers too.

The challenge is that this machine uses resolvers for position feedback. I
haven't dug into the resolver mountings to determine if it would be easier to
replace the resolvers with digital encoders or build a resolver to quadrature
converter board. Resolver to quadrature conversion has been discussed here a
couple of times over the last couple of years. Commercial boards seem to be a
bit pricey for my pocketbook. Analog Devices has a couple of chips that look
interesting. A single reference oscillator chip and two conversion chips
would be required. It should be possible to breadboard a two-axis conversion
board for around $200 US.
--
Keith Bowers - Thomasville, NC