Re: emc help2

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Jon Elson <elson@p...> wrote:

> Everybody says "Oh,they must be making a MINT on that product, look,
> it is just a couple of chips on a PC board!" But, when you price
> this stuff out, you find that everything adds a cost, and

electronic components, these

> days, are NOT cheap! The FPGA on my Universal Stepper Controller
> costs $30 each! The cheapest connectors I could find cost $22 for
> the whole board (there are 6 of them). In small quantity the

boards cost

> over $30 each. It all adds up, and then there's labor to assemble

and test them.

>
> Jon

I'd like to add a hearty, "Yeah, Baby," to Jon's comment. There are
some pretty nice roll-your-own AD, DAC and quadrature decoder
tutorials / board designs floating around on the web (check out the
Seattle Robotics club archives, for example.) I began to entertain
the quixotic fantasy that I'd just make my own controller system for
EMC. Leaving that likelihood aside, when you dig into the Burr-Brown
catalog for the nice pieces to do the job right, the prices'll knock
yer sox off. The same goes for connectors, e.g. the little screw-
together plastic AMP multi-pin cable ends.

On the other hand there are lots of multi-function ISA and PCI I/O
boards out there by fancy makers that sell used for $100-$200. Many
examples seem to do overything EMC wants for servos. Plus there's
lots of surplus Opto-22 stuff for connecting to the real world. I
found a great deal on an aging I/O board and thought I'd just write
drivers for it. I started reading O'Reilley's Understanding Linux
Device Drivers and kept a pile of EMC docs on the nightstand. But I
never wrote the driver--got cable TV instead.

Still, hope springs eternal and maybe one day a sainted member of the
EMC community will sugar coat the hardware interface. I want to be
the first to buy that individual a beer.