Re: [CAD_CAM_EDM_DRO] Re: emc help2

I agree Jon, a very simple looking project will cost you a lot more to
build
than what it appears at first glance.
Jim

----- Original Message -----
From: "Jon Elson" <elson@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, January 30, 2004 10:28 PM
Subject: Re: [CAD_CAM_EDM_DRO] Re: emc help2


>
>
> jackw19x wrote:
>
> >--- 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.
> >
> Oh, yeah, the 4-channel DAC I use on the PPMC DAC card is a 48-pin
> device with leads every .5 mm, and it costs $27! But, it is PERFECT for
> motion control, as it has a return to analog zero built in. (Most can
> return to DIGITAL zero, which would be -10 V on the bipolar DAC.)
>
> > 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.
> >
> >
> But, EMC does NOT USE device drivers! It goes direct to the hardware,
> with X86 instructions like inb and outb.
>
> >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.
> >
> >
> Come to the NAMES show in Detroit at the end of April, and you can buy
> John Kasunich a beer in person. If he gets the HAL enhancement to EMC
> working, he will deserve a LOT of beers!
>
> Jon
>
>
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