Re: Shared Direction pins vs dedicated Direction pins

Tony,

Mariss had ethernet in the orig. G2002 but killed it (wisely, IMO) in
favor of USB...

Ballendo

P.S. I'm surprised we don't see more firewire...

--- In CAD_CAM_EDM_DRO@yahoogroups.com, Tony Jeffree <tony@j...>
wrote:

> I'm amazed that there aren't solutions readily available that use

Ethernet

> connections rather than the parallel port.
>
> Regards,
> Tony
>
> At 14:52 12/02/2003 +0000, you wrote:
> >Bernard,
> >
> >Ditto.
> >
> >And even though the p-port is disappearing,(but will not "really"

be

> >gone for awhile) the current crop of pc-based cnc controllers is
> >including support for additional i/o with the use of another p-

port,

> >or support of generic i/o cards, or usb, game port or otherwise...
> >
> >In other words, it's a solution in search of a problem, IMO.
> >
> >Ballendo
> >
> >P.S. But a neat idea!
> >
> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Bernard R
> ><bwjarandall@c...>" <bwjarandall@c...> wrote:
> > > --- In CAD_CAM_EDM_DRO@yahoogroups.com, Doug Fortune

<pentam@c...>

> > > wrote:
> > >
> > > Doug,
> > >
> > > While there is no technical difficulty doing time division
> >multiplex
> > > with muliple controllers, I don't really see the need. The

current

> > > limitaion is using a single parallel port as the computer
> >interface.
> > > From what little I've seen the G2002 project is well in hand so

the

> > > limited output pins should soon be history.
> > >
> > > From the practical side I could see a lot of people having

problems

> > > with the concept and trouble shooting such a system would be a
> > > nightmare for the average hobbyist with limited technical

knowledge

> > > and virtually no test equipment.
> > >
> > > Bernard
> > >
> > > > re: dedicated Direction & Step pins need 2*N output lines
> > > > vs shared Direction & dedicated Step pins need N+1 output

lines

> > > > (N is number of axes), thus saving output pins which are

limited

> > > > in number on a parallel port, and hence often a constraint.
> > > >
> > > > Chris L wrote:
> > > >
> > > > > >>It would appear to be for some type of "single axis at a

time

> > > positioning"
> > > >
> > > > Doug wrote:
> > > > > >Absolutely not!
> > > > > >This is a general scheme for lathes, mills, routers and
> >hexapods
> > > >
> > > > > Maybe by a "hand cranker".... but, On a CNC mill or

Router ??

> > > Now I am
> > > > > lost..... Even on my simple 3 axis router, I assure you I

can

> >and
> > > do
> > > > > have more than one motor turning, and in opposite

directions at

> > > any
> > > > > given time, even for simple 2d profiles.
> > > >
> > > >
> > > > Hi Chris:
> > > >
> > > > Yup, lots of motors turning simultaneously at different

speeds,

> > > > accelerations and directions, thats how S&D motor drivers work
> > > > (as you well know!).
> > > >
> > > > Yes, I think you are missing something obvious.... the Step
> > > > signals to the motor drivers are of the order of 1 uS (1
> >millionth
> > > > of a second). Apparent smooth motor motion results from

emitting

> > > > one of these pulses (say 20,000 times/sec or once every 50
> > > millionths).
> > > >
> > > > In other words, you could have many (50 channels in this

example)

> > > > sharing a common direction pin, and neither the motors nor the
> > > human
> > > > would be able to detect any measurable difference. However

the

> > > Geckos
> > > > (much as I like them) have a hold-time constraint on the
> >Direction
> > > line
> > > > which precludes their use in a "shared-direction" scheme.
> > > >
> > > > <more written offline to Chris>....
> > > >
> > > > Doug Fortune
> > > > http://www.cncKITS.com
> >
> >
> >Addresses:
> >FAQ: http://www.ktmarketing.com/faq.html
> >FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> >Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
> >
> >Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> >Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> >List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com,

wanliker@a...,

> >timg@k...
> >Moderator: pentam@c... indigo_red@q... [Moderators]
> >URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> >
> >OFF Topic POSTS: General Machining
> >If you wish to post on unlimited OT subjects
> >goto: aol://5863:126/rec.crafts.metalworking or go thru

Google.com to

> >reach it if you have trouble.
> >http://www.metalworking.com/news_servers.html
> >
> >http://groups.yahoo.com/group/jobshophomeshop I consider this to

be a

> >sister site to the CCED group, as many of the same members are

there, for

> >OT subjects, that are not allowed on the CCED list.
> >
> >NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING
> >THEM. DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO

EXCEPTIONS........

> >bill
> >List Mom
> >List Owner
> >
> >
> >
> >Your use of Yahoo! Groups is subject to

http://docs.yahoo.com/info/terms/

>
> Regards,
> Tony