Re: [CAD_CAM_EDM_DRO] Re: Windows and black boxes

Marris:

I agree on all points. If the price is the same as a black box pulser,
then why not! . If I am to code a program for a solution of a black box, I
would certainly prefer this option. I hope the constant velocity works out,
I will be looking forward to giving it a test drive. The spectral purity is
definitely something that will be a godsend to us windows guys. While I can
fool the system to get good granularity, the purity always suffers due top
other constraints, it is my biggest worry on my 50,000PPI engine.

Art
Master5 Software
http://users.andara.com/~fenerty/master.htm

----- Original Message -----
From: "mariss92705" <mariss92705@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Friday, January 25, 2002 9:58 PM
Subject: [CAD_CAM_EDM_DRO] Re: Windows and black boxes


> Hello Art and others,
>
> Indeed the "devil is in the details". The details in this instance is
> a balance scale where a "black box" is on side and a PC is on the
> other side. The ideal is where a balance is struck. Here's how I am
> looking at it:
>
>
> (1) No Black Box:
>
> Pros:
>
> No hardware is always cheaper.
> Maximum flexibility; no hardware constraints and formats.
> Upgrades, improvements, etc. Can be done via download.
> Complete internal control of product, not externally dependent.
> No hardware related support necessary.
>
> Cons:
>
> Low step pulse frequency.
> Non-linear and poor step pulse granularity.
> Step pulse "jitter", i.e. poor spectral purity.
> Step pulse timing "donkey work" burden placed on the PC.
> Adding more axies makes the above even worse.
>
>
> (2) Dumb Black Box generates Step pulses only:
>
> Pros:
>
> Even and very fine step pulse frequency resolution.
> No granularity or jitter problems.
> Reduced burden on the PC.
> High step pulse frequencies easily available.
> Additional axies are less of a burden.
> Maximum flexibility because PC generates all motion routines.
>
> Cons:
>
> Hardware costs more than $0.
> Though less, the PC burden is still significant.
> Still have to handle the nuts and bolts of motion routines.
> High communications bandwidth. Parallel port necessary.
>
>
> (3) Smart Black Box takes care of motion routines:
>
> Pros:
>
> Need to only supply coordinates, lin or circ data, etc.
> Much less real-time computational burden on PC.
> Low bandwidth serial ASCII string communications.
> Costs the same as the "Dumb Black Box"
>
> Cons:
>
> Inflexible "canned" motion control routines.
>
>
> (4) Genius Black Box does everything! No PC needed!
>
> Pros:/Cons:
>
> This gets back to and becomes option (1) in a curiously circular way.
> It is only meant only to point out there is a very tricky balance
> between (3) and (4). That is where the "detail devil" is.
>
> Seriously, in my opinion option (1) will forever have a problem with
> the "Cons:" mentioned above. There is no hardware mechanism in a PC
> to generate evenly distributed granularity for step pulses. This
> requires external hardware to do it natively.
>
> By offering to make the whole thing open with software and hardware,
> I feel there will be people who use their ingenuity to find where the
> proper balance is.
>
> I will build the hardware cheaper than anyone else, which is what I
> expect to get out of this, should it fly.
>
> Mariss
>
>
>
>
> --- In CAD_CAM_EDM_DRO@y..., "Art Fenerty" <fenerty@h...> wrote:
> > Hi All:
> >
> > I just got back from vacation and have followed this thread with
> great
> > interest. The "black box" threads have been running for the last
> year or
> > more, but I notice the discussion getting more and more detail
> oriented as
> > it evolves over time. As the saying goes "the devil is in the
> details"
>
> > Art
> > Master5 Software
> > http://users.andara.com/~fenerty/master.htm
>
>
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