Message #23413 Re:DeskNC - CNC Pro 3x as fast as EMC???

Larry,
What added cost is there to program the PIC? It
is obvious you have mastered PICs! A person going with
your suggestion now has to add more to his plate.
I say build a simple controller capable of 6amps at
60 volts per phase. The circuit has been around for 30 years!
It uses cheap chips and almost all Radio Shack parts. Where can
you find such a diagram, you ask? Well look I have a website TOO!

http://www.geocities.com/crankorgan/

(now I feel unpure!)


I think PICs are cool! but to say they are cheaper than
other chips is not true. Cost is relative. Debugging a circuit
is tough enough for a beginner without adding more hurdles. Time
is money.

John

--- In CAD_CAM_EDM_DRO@y..., "Larry Edington" <ledington@c...> wrote:
> To: kleinbauer@j...
>
> Let me try to clarify what I said in #23413. Also be aware, I've
never tried
> to sell anything in this list. I have recommended products that I
have
> purchased and use.
>
> First, a little bit about what I do. I'm an electronics engineer /
> programmer that worked for a fortune 100 company up until 3.5 years
ago when
> I got fed up with the big city and moved to the Ozarks to work for
myself. I
> design electronics and write software for a living. I do CNC for a
hobby.
> It's likely that several people on this list have computer products
that
> have the results of my work inside them.
>
> Building a stepper motor controller is not a difficult task when
dealing
> with a low current and low voltage standard bipolar drive. Unipolar
is even
> easier but I prefer bipolar.
>
> Buying an L297 qty 1 from Mouser is $5.41
> Buying a PIC16F870 qty 1 from Digikey is $4.63
>
> Since the PIC microcontroller can replace the L297 easily, and add
new
> features to the controller, it seems to be very logical to me. The
L297 is
> the 'logic' device in the circuit. Anytime you can replace a hard
coded
> device with a more flexible, reprogrammable, cheaper device it is
logical.
> Once you have the standard stepper drive working, you can then add
new
> features like microstepping by just changing the software in the
device. You
> can also add encoder feedback to the microcontroller circuit by
simply
> adding 2 resistors, the encoder and some code. Let's see you do
that with an
> L297. Add an L298 for $3.20 and you have a 2 amp 40 or so volt
controller.
> Want higher voltage or current? Just use Mosfets intead of the
transistor
> based L298.
>
> But, the time spent building such a controller usually isn't logical
> economically. Unless you plan on selling it to others as a
commercial
> product. It would cost more in time for me to build one than it
would to buy
> a Gecko or other low cost unit.
>
> For someone that wants to learn something, then the value of the
education
> is worth far more than the difference in cost. I certainly wouldn't
want to
> discourage experimentation for the pursuit of knowlege.
> But sometimes it is just more logical to buy something that works
out of the
> box than to spend time building it.
>
> later,
> Larry E.
>
>
>
>
>
>
>
>
>
> ----- Original Message -----
> From: <kleinbauer@j...>
> To: <CAD_CAM_EDM_DRO@y...>
> Sent: Thursday, April 19, 2001 8:22 AM
> Subject: [CAD_CAM_EDM_DRO] Re: DeskNC - CNC Pro 3x as fast as EMC???
>
>
> > Hi,
> > I am only putting forth some obsevations. I also have a problem
> > with people constantly hawking there wears VIA this conference.
They
> > tell people certain ideas are a waste of time, only to have a buy
> > this solution. I am sure the man who designed Gecko products
started
> > out using simpler designs. If building it yourself is a waste of
> > time, then I say forget retro fitting and buy a new machine!
> > Message 23413 is what I am talking about. You don't want to
build
> > a controller use a PIC instead. What logic!
> >
> > John