[CAD_CAM_EDM_DRO] Serail port CNC (was RE: Why not Nintendo CNC? (was Re: Palm CNC))

The biggest problem you may find with using a serial port -> parallel port
converter for CNC may be the parallel port update rates.

An IBM PC compatible serial port runs at a maximum rate of 115K bits per
second. This means that the parallel port output state can only be changed
11,500 times per second. A modern parallel port can be changed between
2,000,000 and 8,000,000 times per second. The update rate on the parallel
port is one factor (after CPU speed) in determining how fast
step-and-direction pulses can be sent. A serial-to-parallel converter could
limit the step rate to a four-hundredth of what you could get with a direct
parallel port.

For my next CNC machine, am using serial port interfaced stepper
drivers. I had a PC board made to drive two motors from a single, daisy
chained, serial port. To handle the speed problem, I have done two things:

1) I transmit motor phase information, not step-and-direction.
2) I allow enhanced serial ports, and support speeds 4 times
faster than the PC standard.

This is not, however, compatible with step-and-direction CNC software. I
don't know if EMC supports a direct-phase output module.

-- Carl


At 09:05 AM 1/3/2003 -0500, you wrote:

>I'm still feeling my way around this CNC stuff so this suggestion may be
>full of fault and unsuitable. There are comparatively inexpensive devices
>which used to be used with printers (back when serial printers were the
>norm, but PC's used parallel ports) which will do serial to parallel
>conversion. This may be a way out for people who only have serial ports on
>their pocket PC's, but need a parallel input to their controllers.
>
>
>
>Jeffrey Goldberg, President
>
>Washington Computer Services
>140 58th Street - Suite 8F
>Brooklyn, N.Y. 11220
>
>Tel: (718) 491-6100
>Fax: (718) 765-1973
>email: jeff@...
>
>If you can describe what you want your network to do,
>We can design it, install it, and get it working
>Always with an eye to exceeding your expectations
>
>
>-----Original Message-----
>From: abbylynx <abbylynx@...> [mailto:abbylynx@...]
>Sent: Friday, January 03, 2003 8:45 AM
>To: CAD_CAM_EDM_DRO@yahoogroups.com
>Subject: [CAD_CAM_EDM_DRO] Why not Nintendo CNC? (was Re: Palm CNC)
>
>
>I've been considering reccyling my old pocket PC into a CNC
>controller, actually. It's a little old Casio E-105, - nice spec
>machine with a colour 16-bit touch screen display and 133Mhz
>processor. You'd just slot the G-code files in on a compact-flash
>memory card, or get the wirelessly through a Wifi network.
>
>The only thing with all of these designs (PocketPC, Palm, GameBoy
>etc.) is that all these small devices are only ever equipped with a
>SERIAL connection, which means in addition to everything else you'll
>need some kind of small dedicated Microcontroller to take serial
>commands and direct the mill/lathe/spine-drilling robot/etc to do
>something meaningful with the command. However, if you have a nice
>(expensive) Roland Mill that already has a serial connection on it,
>then you don't need much more than a simple terminal program that
>streams commands and waits for a response before sending the next.
>
>Otherwise you've got to do some work with a uController like the PIC.
>
> > At 21:54 02/01/2003 +0000, you wrote:
> > >Funny you should mention the Nintendo Game Boy for CNC, Singer has
>a silly
> > >looking little sewing machine that does embroidery that is
>controlled by a
> > >game boy. Check out http://www.sewandserge.com/s-izek.htm to see
>this
> > >little guy.
> > >
> > >John Guenther
> > >'Ye Olde Pen Maker'
> > >Sterling, Virginia
> > >
> > > > -----Original Message-----
> > > > From: Tony Jeffree [mailto:tony@j...]
> > > > Sent: Thursday, January 02, 2003 14:10 PM
> > > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > > Subject: [CAD_CAM_EDM_DRO] Why not Nintendo CNC? (was Re: Palm
>CNC)
> > > >
> > > >
> > > > At 18:51 02/01/2003 +0000, you wrote:
> > > > >Thanks fella's.....
> > > > >
> > > > >keep your Ears "peeled". If you find something interesting, or
>more that
> > > > >is CNC palm related, please mention it. If the robotics guys
>are so
> > > > >heavy into it, It'll make it to the CNC arena as soon as a
>programmer
> > > > >type spends some time with it.
> > > > >
> > > > >I too saw some of the development proggys...... Very much like
>VB. I
> > > > >have only fiddled with VB mostly in Access, but understand its
>methods
> > > > >in a very limited way.
> > > >
> > > > Looking at the Nintendo "Game Boy"s that we finally gave in &
>bought for
> > > > our kids this Xmas, it struck me that one of those could form
>the
> > > > basis of
> > > > an interesting controller, pendant, display unit or similar.
>$100
> > > > gets you
> > > > a colour screen, a bunch of push buttons, a processor, plug-in
>memory
> > > > modules, and an external I/O port (used for multi-player games,
>but no
> > > > doubt could be used as a means of interfacing to the driver
>stage
> > > > of a CNC
> > > > control).
> > > >
> > > > Has the added advantage that when you're done making swarf, you
> > > > could plug in the latest "shoot-em-up" game too...
> > > >
> > > >
> > > > Regards,
> > > > Tony
> >
> > Regards,
> > Tony
>
>
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>OFF Topic POSTS: General Machining
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>http://groups.yahoo.com/group/jobshophomeshop I consider this to be a
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Carl Mikkelsen
Oasis Semiconductor, Inc.
201 Jones Road
Waltham, MA 02451
(781) 647 8775