Re: posting

PCSHAPER@... wrote:

> From: PCSHAPER@...
>
> To anyone who cares to respond,
>
> I have a Shasuka (sp?) vertical mill with an old Summit-Bandit
> controller.

Is that a Shizouka ?

> Needless to say, it is costing me a fortune to keep it working! This
> particular
> mill has servo motors and resolver position sensors. The Servo board
> is
> working
> OK, but something else is messed up. I am trying to locate someone who
> knows
> an inexpensive PC based 3 axis servo control board that can work with
> resolvers.

I had a similar problem, using an Allen-Bradley, and then EMC with an
ancient
GE servo drive with resolvers. I replaced the resolvers with 1000
cycle/rev
encoders, giving 4000 counts / rev. Multiply by 5 TPI, and that is a
resolution
of 20,000 counts/inch, or .00005". I got these encoders for $75
surplus, they
are certainly around.

> I also would like to know if anyone has a schematic of the resolver
> board (2
> boards
> bolted together) and any programming information on this board. I am
> an
> electronics
> engineer and am interested in making an interface between the PC bus
> and this
> card
> so that I can control the machine directly from a PC.

There are commercial resolver to quadrature interpolator/converters.
They generally
include all the stuff to excite the resolvers, amplify the signals and
decode them.
The only chip level stuff I know about is the Analog Devices 2S80
series, which
are darned expensive chips. But, I'm sure other outfits know how to do
this without
the expensive AD parts. Old Qume daisy wheel printers had equivalent
chips
for their magnetic position encoders (inductosyns are kind of planar,
ironless
resolvers). I never got a print so I could figure out how to reuse
these chips.

If you want to do web searching, you might try keywords like
interpolator and
inductosyn, as well as resolver.

But, if you have to purchase the interpolator boxes at new prices, it
might be
cheaper to get shaft encoders surplus, instead.

Jon