Re: How to get a signal to controll spindle speed?

["Ian W. Wright" <ian-at-iw63.freeserve.co.uk>]

Hi John,

I'd be interested in the PIC stuff, I'm trying to get to grips with PICs at
the moment and it would be good to do something useful instead of just
flashing LEDs!!

Best wishes,
Ian
--

Ian W. Wright
Sheffield, UK
----- Original Message -----
From: "John Sheahan" <jrsheahan-at-optushome.com.au>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Sunday, May 19, 2002 12:59 AM
Subject: Re: How to get a signal to controll spindle speed?


>
> Hi Ray
> most obvious solution would be a serial adc like maxim's
> max1232. needs 3 wires out the parallel port.
>
> hovever this is proving that its possible to extend
> ancient tech like the parallel port to ridiculous extents.
>
> Is there any obvious reason why USB could not be used
> instead? much more flexible.
>
> A more reasonable solution would be to stuff a small
> opto interruptor or hall effect onto the shaft, connect that
> to a single chip PIC,  and get serial speed messages from that.
> Serial could then go into  standard serial ports, or usb serial,
> or a multiport serial card
> for the wealthy ones. usb devices on cypress stuff is pretty
> easy to add.
> I can post code and circuits, even a couple of proto boards and
> programmers  for the PIC if people are interested.
>
> What kind of feedback comes from the laser as to power?
> And I thought the thread started with a PWM request. where did analog
> come in? must have missed something key.
>
> John
>
>
> On Sat, May 18, 2002 at 09:31:55AM -0400, Ray Henry wrote:
> >
> >
> > List
> >
> > I've got to say that I find this thread fascinating.  Nice creative
solutions
> > to getting some kind of analog signal out of a parport.  How would we
close
> > the loop by getting spindle or laser intensity back into the emc without
> > using a full servo board solution?
> >
> > Ray
> >
> > On Saturday 18 May 2002 06:25, you wrote:
> > > On Friday 17 May 2002 15:36, you wrote:
> > > > Hi list,
> > > > Can anyone tell me how typically a mill with
> > > > controllable spindle speed out the emc is being set
> > > > up? I want somehow a possibility to controll
> > > > laserpower by the emc software. I think I could use
> > > > the "spindle speed" command for this purpose.
> > >
> > > you could use a simple  555 timer with an electronic variable resistor
> > > these usually have up/down logic inputs which 'move' the wiper tap
> > > and are very cheap & cheerful ,
>
>