Re: STG and Parallel Port

["Les Watts" <leswatts-at-alltel.net>]

I did try using the s word along with an M3.... program execution stops.

I think the problem might be that I am using bridgeporttask as the task
controller
and minimillio as the io controller.

I will just have to play around with it and see what I can get on a parallel
port.

If the latest cvs handbook has something about this I can't see it just yet.
I don't see anything about it on the html handbook on the site.
I am on a windows box here in the office and would have to play around a bit
to be able to download cvs. If this stuff is not documented well I will take
notes,
write up what I find, and post it.

I would expect a spindle control to check for actual spindle rotation rather
than just a blind command. I can put an inductive sensor or hall effect
device
(magnetically biased) near the hex collet nut on the spindle to create a
quick and
dirty tach. I can clean this signal up and convert to a digital pulse rate
or analog
voltage porportional to rpm with a few spare components from the electronics
parts bins. At minimum I just want a digital signal to indicate that the
spindle
is in fact turning when activated, although a speed feedback signal is
almost
as easy if EMC can now handle it. It would be nice to have this come out
on spare STG i/o but it is not really necessary. Remember the spindle
motor is effectively an integrator- so in other words a control system need
only have a bandwidth of a fraction of a Hz. I think it easily can be
handled as a non real time task.

Les

Leslie Watts
L M Watts Furniture
Tiger, Georgia USA
http://www.alltel.net/~leswatts/wattsfurniturewp.html
engineering page:
http://www.alltel.net/~leswatts/shop.html
Surplus cnc for sale:
http://www.alltel.net/~leswatts/forsale.html
----- Original Message -----
From: "Paul" <paul.corner-at-tesco.net>
To: "Multiple recipients of list" <emc-at-nist.gov>
Sent: Tuesday, November 19, 2002 3:53 PM
Subject: Re: STG and Parallel Port


>
>
> Hi Jon
>
> For a conventional three axis mill, the number of IO used on an STG card
is,
> at most, 15 pins. Amp enable & fault, + & - limit, and home switches. This
> leaves plenty of IO for spindle control IF it could be utilised.
> Whist it is possible to run a (slightly) hacked bridgeportio to make use
of
> the spare IO pins, there is a danger of stgmod and bridgeportio fighting
over
> the same pin..
> As you have found out, the easiest way to avoid race conditions is to pass
> all IO read/writes through the realtime interface. This has the advantage
> that just one parallel port could be used for all the basics of control. I
> have been running some simulations this afternoon with steppermod and once
> I've done some further tests, will check the changes in to Sourceforge.
>
> Regards, Paul.
>
>
> On Tuesday 19 Nov 2002 4:43 am, Jon Elson wrote:
> > The STG I/O is all taken up with limit and home switches, amp faulta and
> > amp enables, etc.
> > So, yes, you need to use another parallel port for the auxilliary
control.
>