RE: Parallel port isolation

Hans;

I wrote Doug Yeager with some questions about his software. He responded
quickly and seems to be interested in his customer's needs. The price is
certainly reasonable - probably worth the money just to evaluate it. Isn't
feed hold available from a pinout on the parallel port? I recall reading
something to this effect in the demo notes.

Is ramping supported in feed hold? I forgot to ask him this one.

Doug

> -----Original Message-----
> From: hansw [SMTP:hansw@...]
> Sent: Monday, November 22, 1999 8:50 PM
> To: CAD_CAM_EDM_DRO@onelist.com
> Subject: Re: [CAD_CAM_EDM_DRO] Parallel port isolation
>
> From: hansw <hansw@...>
>
> Doug,
> Yes I have a few ot them, if you are referring to the 5Vin to 9Vout...
> they work just fine, but there is really no need to use them as a simple
> transformer isolated PSU achieves the same thing. Remember isolation is
> limited to the signal side, because there will be a common ground
> through the 115V AC outlet.
>
> I did a design for NMEA ( the boat lot not nema) that requires complete
> isolation on certain lines, and then I used the DC-DC converters to that
> end...
>
> It is also a requirement in medical electronics, but for a mill, what
> you are trying to archieve will be done by a good quality transformer
> based PSU..
>
> CNCPRO.EXE I have it and like it, because the interface is simple and
> easy to use. You name sake Doug does a good job of supporting it.
>
> I am unclear what you mean by feed rate override..
>
> You can increase and decrease the feed rate while a cut is being done.
> The amount you increase the F/R by is set in the setup. I have mine so
> that I can increment/.decrement F/R by 0.1ipm This is done by pressing
> the "F" for increase and "f" for decrease.
> Stop is done by pressing the space bar, and all feed's stop. You then
> have the option to continue or over ride by doing manual jog...
>
> Is that what you meant ?
>
> regards
> Hans Wedemeyer
>
>
>
>
> "Harrison, Doug" wrote:
>
> > Hans;
> >
> > Optoisolation of the output (or is it the input - can't remember)
> > requires
> > an external power supply. Jameco sells a DC-DC converter for about $6
> > that
> > will do this. I used one on a servo system for the limit switches.
> > The
> > opto chips and converter could all be put on a breakout board with all
> > necessary screw terminals for connection to the machine, limits,
> > etc.
> >
> > Plans at this time are to stick with DOS. I am mulling over Doug
> > Yeager's
> > CNCPro right now. The price is right, but I can't determine from the
> > demo
> > if the software performs to my level of expectation. The lack of a
> > feed
> > rate override knob troubles me too. Bridgeport used keyboard FRO on
> > the
> > newer CNC's and I don't like it at all. Microkinetics uses keyboard
> > feed
> > hold and I know from experience this is not safe. One tap stops the
> > feed.
> > Tap it two times (in a panic) and it keeps going.
> >
> > Doug
> >
> >
> >
> > > -----Original Message-----
> > > From: hansw [SMTP:hansw@...]
> > > Sent: Monday, November 22, 1999 6:19 PM
> > > To: CAD_CAM_EDM_DRO@onelist.com
> > > Subject: Re: [CAD_CAM_EDM_DRO] Parallel port isolation
> > >
> > > From: hansw <hansw@...>
> > >
> > > Doug,
> > > Depends on the type of opto coupler device. The H11L1 is cheap and
> > will
> > > have no problem doing 30KHz, I think it's rated in the low
> > > megabits/second range.
> > > The parallel port can handle 30K bytes second, it's more a question
> > what
> > > can the program do and the OS it's running under.
> > >
> > > I think the big mess with optoisolation is the number of couplers
> > needed
> > > for a parallel port, which would be 17 as I see it. and then there's
> > the
> > > question of if you want bi-directional abaility it's even more
> > > complicated...
> > >
> > > Hans Wedemeyer
> > >
> > >
> > >
> > > "Harrison, Doug" wrote:
> > >
> > > > Hans;
> > > >
> > > > I have also considered the optoisolation approach but was
> > concerned
> > > > that
> > > > 30Khz might be too much for opto devices. (I am using
> > > > microstepping.) Are
> > > > the inexpensive opto chips capable of this speed? Is the parallel
> > port
> > > > reliably capable of this speed?
> > > >
> > > > Doug
> > > >
> > > > > -----Original Message-----
> > > > > From: hansw [SMTP:hansw@...]
> > > > > Sent: Monday, November 22, 1999 4:20 PM
> > > > > To: CAD_CAM_EDM_DRO@onelist.com
> > > > > Subject: Re: [CAD_CAM_EDM_DRO] Parallel port isolation
> > > > >
> > > > > From: hansw <hansw@...>
> > > > >
> > > > > Doug,
> > > > > It would be wrong to say it can't happen, however I think if the
> > > > circuit
> > > > > is correctly designed and a good circuit board is used, the
> > problem
> > > > is
> > > > > no greater than when a printer is connected.
> > > > >
> > > > > Remember printers use stepper motors, and some of the heavy duty
> > > > page
> > > > > and line printers use very large stepper motors and no
> > isolation,
> > > > and
> > > > > some of the older version pen plotters also used large stepper
> > > > motors...
> > > > >
> > > > > Stepper drivers are relatively slow devices, and putting an opto
> > > > > isolator in each signal line is not problem except expense and
> > board
> > > > > size.
> > > > >
> > > > > regards
> > > > > Hans Wedemeyer
> > > > > http://home.swbell.net/hans_w
> > > > >
> > > > >
> > > > > "Harrison, Doug" wrote:
> > > > >
> > > > > > The notion of using the Parallel port to control machinery has
> > > > > > fascinated me
> > > > > > for 15 years. However, as one who obeys speed limits and
> > never
> > > > uses
> > > > > > stairs
> > > > > > without holding on to the rail, I am naturally concerned about
> > > > hooking
> > > > > > my
> > > > > > non-isolated parallel port I/O to an 80 volt amplifier
> > controlling
> > > > > > inductive
> > > > > > devices.
> > > > > >
> > > > > > Has anyone experienced fried computer syndrome from stray
> > currents
> > > > in
> > > > > > large
> > > > > > stepper systems? I know this can be a problem with servo
> > systems,
> > > > > > usually
> > > > > > from ground loops.
> > > > > >
> > > > > > Doug Harrison
> > > > > >
> > > > > >
> > > >
> > ------------------------------------------------------------------------
> > > > > > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for
> > the
> > > > > > discussion of shop built systems in the above catagories.
> > > > > > To Unsubscribe, read archives, change to or from digest.
> > > > > > Go to: http://www.onelist.com/isregistered.cgi
> > > > > > Log on, and you will go to Member Center, and you can make
> > changes
> > > > > > there.
> > > > > > For the FAQ, go to http://www.ktmarketing.com/faq.html
> > > > > > bill,
> > > > > > List Manager
> > > > > >
> > > > > >
> > > > ----------------------------------------------------------------
> > > > > > [Image]
> > > > > > Click Here
> > > > > >
> > > > >
> > > > > > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for
> > the
> > > > > discussion of shop built systems in the above catagories.
> > > > > To Unsubscribe, read archives, change to or from digest.
> > > > > Go to: http://www.onelist.com/isregistered.cgi
> > > > > Log on, and you will go to Member Center, and you can make
> > changes
> > > > there.
> > > > > For the FAQ, go to http://www.ktmarketing.com/faq.html
> > > > > bill,
> > > > > List Manager
> > > >
> > > >
> > ------------------------------------------------------------------------
> > > > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> > > > discussion of shop built systems in the above catagories.
> > > > To Unsubscribe, read archives, change to or from digest.
> > > > Go to: http://www.onelist.com/isregistered.cgi
> > > > Log on, and you will go to Member Center, and you can make changes
> > > > there.
> > > > For the FAQ, go to http://www.ktmarketing.com/faq.html
> > > > bill,
> > > > List Manager
> > > >
> > > >
> > ----------------------------------------------------------------
> > > > [Image]
> > > > Click Here
> > > >
> > >
> > > > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> > > discussion of shop built systems in the above catagories.
> > > To Unsubscribe, read archives, change to or from digest.
> > > Go to: http://www.onelist.com/isregistered.cgi
> > > Log on, and you will go to Member Center, and you can make changes
> > there.
> > > For the FAQ, go to http://www.ktmarketing.com/faq.html
> > > bill,
> > > List Manager
> >
> > ------------------------------------------------------------------------
> > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> > discussion of shop built systems in the above catagories.
> > To Unsubscribe, read archives, change to or from digest.
> > Go to: http://www.onelist.com/isregistered.cgi
> > Log on, and you will go to Member Center, and you can make changes
> > there.
> > For the FAQ, go to http://www.ktmarketing.com/faq.html
> > bill,
> > List Manager
> >
> > ----------------------------------------------------------------
> > [Image]
> > Click Here
> >
>
> > Welcome to CAD_CAM_EDM_DRO@...,an unmoderated list for the
> discussion of shop built systems in the above catagories.
> To Unsubscribe, read archives, change to or from digest.
> Go to: http://www.onelist.com/isregistered.cgi
> Log on, and you will go to Member Center, and you can make changes there.
> For the FAQ, go to http://www.ktmarketing.com/faq.html
> bill,
> List Manager