Re: New project...PCI based servo control board

[Malte Rütemann <malte-at-micompan.de>]

Am Donnerstag, 27. März 2003 22:13 schrieben Sie:
> Craig wrote:
> > GEEZ... I no sooner get my last message and you have it
> > designed...:)  I don't have time for a detailed response
> > now (I need to do some real work today..:), but with a
> > quick read I can say I pretty much agree with your
> > thinking.
>
> I've been thinking about this for nearly a year...
> This conversation and others in the last couple of
> months have really got the gears turning, so what
> seemed like a quick response really is the result
> of quite a bit of time already spent.
>
> >  I'd like to consider a serial expansion bus.....
>
> I want to stay away from anything that requires
> FPGAs, ASICs, or any LSI on the I/O board.  I'm
> hoping to keep the tricky stuff on the first
> board, and make the I/O board simple enough that
> it can be truly open - anyone who can solder can
> build it with parts from Digikey.
>
> > But ribbon cable is pretty cheap (if not robust).
>
> My attraction to ribbon isn't cost, it's simplicity.
> With all the brains on board #1, the I/O board is
> buffers, relays, optos, only - nothing tricky.
> There may be better solutions than ribbon, but
> the key is many conductors with simple signals
> on them.  I agree that a round shielded cable
> would be better.  I just took a quick look at
> the Digikey catalog - how about SCSI-3 connectors
> and cables?  68 pins, and nice shielded cables
> are available, as well as less expensive ribbon
> versions.  Obviously we would have to make sure
> the connectors are labeled - wouldn't want to
> plug a disk drive into the CNC port.  Although
> if every signal on the cable is 5V or less, you
> probably wouldn't hurt anything even if you did.
>
> This is the ribbon version, $13.33 each
> http://rocky.digikey.com/WebLib/Assmann/Web%20Photos/AK-Y2301.jpg
>
> Here is the round version, $29.60
> http://rocky.digikey.com/WebLib/Assmann/Web%20Photos/AK-Y1301.jpg
>
> Here is the board mount connector, $6.70
> http://rocky.digikey.com/WebLib/Amp/Web%20Data/787082.pdf
>
> > Thanks for brain cycles... I will reflect / reply
> > more on this more tonight.
>
> I will do the same.  I've had a design in the back of my
> head for a step pulse generator, and while walking the dog
> yesterday I realized that with minimal mods it could also
> become an analog output (pseudo-PWM).  I will draw it up
> in block diagram form and post it in a day or so.
>
> John Kasunich
As Idea, I don't know how much pins you need, but try 2 D-Sub 25 cabels. 50 
Pins should be enough, and the cabel ist very cheap.
In the PC, there is than one connector on the board, and the second on a 
seperate slot, like on some IO-Serial boards.

Malte