Re: [CAD_CAM_EDM_DRO] Re: G320s, New and Improved!

mariss92705@... wrote:

> Jon,
>
> Good afternoon! The only way illegal transitions can occur are if (1)
> the channel A and B lines are shorted together or (2) a non-
> quadrature encoder is used such as using the least 2 bits of an
> absolute encoder. In either case the error will be caught due to the
> ensuing consequences.

Well, I was talking about momentary transitions due to large noise
pulses. I suspect this is what was happening with the installation
troubles in the plasma cutter systems. I noted in my research on
the topic when I started down this path some years ago that EVERY
major encoder counter chip makes a big fuss over the quality of
THEIR proprietary digital filtering of the encoder signals. I took this
to be a sign that illegal transitions and other bad encoder signals are
quite a problem, and the customers must be demanding it. Plain
RC filtering may well be good enough, one would have to record
some of the nasty transients to know for sure.

<embarrasing buttering-up deleted>

> My first point is experience has shown the last 10% of performance
> consumes 90% of the final cost. My second point is a cost-beneft
> ratio exists for almost anything one undertakes.

This is true!

> The second point implies the existance of a "sweet point" or value
> where performance divided by cost is at a maximum. It takes effort to
> find this optimal mix and it is the cause of satisfaction if one
> comes close.
>
> Compared to the G320, clearly your servodrive has more features, not
> the least of which is tacho feedback. However it would cost between
> $500 to $1,000 to the end user when all is said and done. Witness the
> price of any mainline industrial servodrive.

Well, there are a couple of Copley amps in this class (90 V, 10 A) with
tach feedback in the $200 range. Supposedly that is quantity 1!
This is why I stopped further efforts to sell these as complete units.

> There are Volkswagens and there are Ferraris and both are cars. Both
> will get you from here to there and both beat walking. My design
> efforts have focused on the utilitarian end. Your design is a high
> end one and obviously works. With that said I would warmly encourage
> you to produce it for sale, there is room for both. It would place me
> on a more even footing as well since then I would be able to offer
> helpful suggestions on how to improve it:)

No, given that Copley is not the only outfit with low-cost servo amps,
I just can't see any reason to try to get into this market. As for the
higher end, there are a BUNCH of companies with very well-known names
in the business, Servo Dynamics, Kollmorgen, Pacific Scientific, etc.
And it would be almost impossible to penetrate much of that business.
I'm going to concentrate on areas where I am making something that
is pretty much unique.

If eBay had been operating in 1997 like it does today, I would not have
made these servo amps, either. I would have just bought some nice
ones on eBay and slapped them into my machine.

Jon