Re: PC based CNC system architecture

Jon Elson wrote:

>
>
> Wally K wrote:
>
> > 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:
> Sorry, I probably have put enough info out on this list to answer
> the question, but I didn't put it all there in the same place.
>
> So, the whole idea of what I'm doing is to make a mix and match
> system. You select cards with only what you need.
>
> The axis boards are 4 axes each. There is an encoder counter,
> and a 16-bit DAC. There will be a 4 axis stepper rate generator
> which connects to the encoder counter for open-loop operation.

Wally K. replys

would this list be correct for plug in cards.

1) 4 axis servo card.
2) 4-16 bit DAC's.
3) 4 axis stepper rate generator card.
4) 4 axis encoder counter card.
5) Digital I/O card. With 16 opto inputs and 8 solid state relay
outputs.

> Jon replys:
> The encoder counter counts the step pulses, so there is no
> possibility of the PC failing to count a step pulse.
> Of course, you can use the encoder counter to count a physical
> encoder for a closed-loop stepper system.

Wally K. replys

If you would use the encoder counter card to count encoder pulses are
there any special requirements for encoder resolution.

> Jon replys:
> The final board is a digital I/O module, which will have 16
> opto-isolated input channels and 8 solid state relay outputs.
> Everything will be on-card, so you don't need any expensive
> opto-22 boards or wire breakout modules.

Wally K. replys

With all the crying i have done about price i hesitate to ask for
something that will add cost. But on your solid state relay
outputs. Do you have a replaceable fuse not a solder type. Having
to unsolder them from opto-22 stuff i think it is worth it. Also i
can tell you that explaining to a customer on the phone what a pico
fuse looks like and how to unsolder and replace it, is an hour job.

> Jon replys:
> There is a
> backplane module which can have up to 8 connectors to
> accept up to 8 of these boards, in any combination you need.
> For a 4 axis system (either stepper or servo) with one
> digital I/O board, there would only need to be 3 boards in
> the backplane. The 5 boards needed for up to 8-axis systems
> would have 2 boards for each group of 4 axes, plus the digital
> I/O board. I guess this is for the hexapod guys.
>
> Jon

Wally K. replys:

So with a 8 slot motherboard. You could have up to 12 axis and 2 I/O
cards.