Re: PC based CNC system architecture

Matt Shaver <mshaver@e...> wrote:

> > Wally K wrote:
> >
> > > After reading Matt Shaver's post about selling this unit for

$800.00

> > > to $1000.00 i darn near fell off of my chair. I would say with

that

> > > price Matt has put this control out of reach of at least 90% of

the

> > > people that would want it.


> Matt wrote:
> This price was based on a configuration that has capabilities equal

to a

> Servo-to-go card (8 channels of DACs, 8 channels of quadrature

decoders,

> and several bytes of digital I/O), it's also a wild guess since I

really

> don't know what the real production cost will be.
>


> > Jon wrote:
> > That's all there is on the board, if you don't want differential

inputs.

> > This and a few decoupling caps comes to $126 - it adds up quick.


> Matt wrote:
> The above configuration would require 5 boards of approximately this
> cost (the cost of the DAC boards must be higher since the Burr-

Brown D/A

> chips are not exactly cheap, and the digital I/O board hasn't been
> invented yet, but I expect it will probably cost about what the
> quadrature decoder boards cost), plus a motherboard/card cage

assembly.

> That's where that number of $800-$1000 comes from.
>

Wally replys:

This is were i loose you. When you say the above configuration...ect
i am not sure what you are talking about. At one point you talk
about 8 channels then later you talk about 5 boards. I do not
understand what these boards are for or what boards are required for
servos and what boards are required for steppers.

> > Jon replys:
> > About the only component change you can make is the terminal
> > strips. There are $36 of Phoenix Contact pluggable screw

terminals

> > on this version. Much cheaper terminals should be available,

although

> > these are 2.5 mm spacing in this design.


> Matt Replys:
> I'm pretty sure .1" (2.54mm) headers with .025" square posts would

fit

> in the same hole pattern and that would save at least $30 of the

$36. I

> still want the nice connectors...
>
> Matt

Wally replys:

You seem to have a billion dollar card cage in here someware with
million dollar connectors. What is wrong with simple cheap header
connectors. And are you physically building a mechanical card cage.


Wally K.