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