Re: PC based CNC system architecture

Matt, thank you for taking the time to answer all of my questions.
I think myself and the others on the list now have a good idea what
you are building.

And one last thing. I am getting the impression you and Jon designed
this to sell to indrustrial people and not necessarily the people on
this list, would that be a fair statement.


Wally K.


P.S.

With the size of daughter card you are talking about i can see why
you are thinking card cage.

--- In CAD_CAM_EDM_DRO@egroups.com, Matt Shaver <mshaver@e...> wrote:
> Wally K wrote:
> > Thanks Matt, You are starting to clear things up for me.
>
> Good!
>
> > Could you tell me what the motherboard consists of. Is it a
passive
> > backplane or does it have smarts on it.
>
> Basically a passive backplane. There is one ttl chip on it for
signal
> conditioning purposes, but that's it.
>
> > On the proposed 4 axis stepper card you are working on. Can you
put
> > more than 1 card in the motherbord.
>
> Yes, 8 cards for a total of 32 motors. Quite an impressive machine,
> difficult to program too..
>
> > Also on the proposed stepper card why does this ignore the digital
> > I/O issue all together.
>
> Because there aren't any I/O bits to turn the spindle on or read the
> home switches, etc. That would involves a different card.
>
> > First, header connectors do not pull apart that easily. But it
would
> > depend on board size. Second, how in the world would anything
unplug
> > inside of a control cabinet.
>
> OK, maybe you're right about that...
>
> > There is no reason to put connectors that unplug on the axis
cards.
> > Once the cards are in place why would you want to unwire them.
> >
> > Connectors that are external to the box can be of use but not
inside.
>
> Well, everything I've ever built, I've had to take apart sooner or
> later. Suppose something goes wrong with a board out in the field,
> someone will have to pull it out and replace it and they may want to
> swap boards around to isolate their problems. I've worked on a lot
of
> cnc machines (doing repairs) and most are really difficult to work
on. A
> common example would be replacing the bridge rectifier modules on an
> older Bridgeport mill. You have to take a bunch of stuff loose
before
> you can even SEE them!
>
> > My point is, depending on card size and layout you do not need
> > expensive backplane connectors and removable external connectors
or a
> > card cage.
>
> The daughter card size is about 4" x 6".
>
> > By the way. Is your layout etched in stone and are you getting
> > boards made yet.
>
> Some boards are made already, although once things are proven out,
> repackaging the basic technology to fit particular applications
would be
> possible. For example, a single board configuration with a fixed
set of
> features adequate for most 4 axis or less machines might be an
> arrangement that better suited the folks participating in this
> discussion.
>
> > I would like to say with the cost and miscellaneous construction
> > issues aside that it sounds like you are making a very nice
control.
>
> It will be especially nice if I can sell some of them!
>
> Matt