AW: digital servo controller to offload the Parallel Port?

["Till Franitza" <xfa-at-isw.uni-stuttgart.de>]

Hi John!
This is an interesting idea. Normally, counter chips are used for this. They
are on i/o-cards that are stuck into the ISA or PCI Bus and then read via
memory mapping, for example. They are not very cheap (888$ for 8 axes) but
they offer a lot. Look at servotogo.com too see what you would have to do to
be "competitive".
Another interesting thing can be seen on http://pico-systems.com/PPMC.html .
The good thing about it is that it can be driven by a laptop (Laptops mostly
dont have isa-slots).
Maybe they have fpgas inside, too.
Two things that are very important in my opinion:
1.: the programming interface has to be clear and simple and fast
2.: the connectors have to be handy. The whole thing must be compact.
I do not want to tell you that there is no need for a new approach, but i
just want to hint at the difficulty of being better than the state of the
art.
Best Regards,
Till

> -----Ursprüngliche Nachricht-----
> Von: emc-at-nist.gov [emc-at-nist.gov]Im Auftrag von John Griessen
> Gesendet: Mittwoch, 18. Dezember 2002 15:36
> An: Multiple recipients of list
> Betreff: digital servo controller to offload the Parallel Port?
>
>
>
> Hello y'all,
>
> If a feedback loop is too much for emc on a PC via standard ports, has
> anyone made a microcontroller digital servo loop controller for emc
> yet?  Who wants one?  How many?  I can design such and nowadays it can
> even be lower cost then microcontrollers/memory when you design it into
> a FPGA system chip.
>
> John Griessen
> Austin TX
>
> On Wed, 2002-12-18 at 01:22, Till Franitza wrote:
> to detect encoder Feedback directly via parallel port whould put a too
> > heavy load on the processor. I do not think it would even work with
> > reasonable resolution.
> > Till
> >
> > > -----Ursprüngliche Nachricht-----
> > > Von: emc-at-nist.gov [emc-at-nist.gov]Im Auftrag von Adam Hunt
> > > Also, could one use the parallel port for quadrature encoder
> feedback IO?
> > >
> > > --adam
>
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