Re: [CAD_CAM_EDM_DRO] Re: Shared Direction pins vs dedicated Direction pins

I tried to write a program for Art Axtein DRO to transfer readings to
another machine
over the network in real time. Unfortunately couldn't compile his program.
So I'm switching to Dan Mauch DRO program. It seems to be written in generic
C.
Basically I will connect 2 machines together - one getting readings, another
displaying
them. It seems to me a simplest way to do multiplexing since SBC are
available now
for as low as $112 US. Its 386 -40 with ISA bus. One can put lots of staff
there,
see book "Build your own universal computer interface" as an example.


Alex

----- Original Message -----
From: Tony Jeffree <tony@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, February 12, 2003 10:00 AM
Subject: Re: [CAD_CAM_EDM_DRO] Re: Shared Direction pins vs dedicated
Direction pins


> 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:
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> >
> >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.
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> >
> >http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
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> Regards,
> Tony
>
>
>
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>
> 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/
>