Re: [CAD_CAM_EDM_DRO] black box specs was Re: interpolation and algorithms of multiple axes

Jeff Barlow wrote:

> Jon,
>
> Congratulations on being the first flaming arrow archer.
>
> I've been designing PC interfaces for years and I'm not convinced any of
> them are all that deterministic.

The PC parallel port is pretty deterministic. The machines I've worked with
lately get about 1 uS of jitter on the transactions in EPP handshaking mode.
That's pretty good, as far as I can tell.

This, of course, requires that the OS be tamed, but that isn't the fault of
the parallel port.

> I am thinking in terms of only the control PC and the motion box on the
> "network". Also there would be no real reason to run a full TCP/IP stack
> on this so a lot of the other noise could go away.

Ahh, yse, that makes it work a lot better. Then, the pseudo-ethernet is
just a fast serial interface.

Jon