Re: [CAD_CAM_EDM_DRO] Re:Smart Box / Dumb Box

Greg Nuspel wrote:

> I like what I see being developed here. It looks like there will be systems
> that you can set up with a dumb board and steppers. When your budget allows,
> you can expand it to servos with a smart board. I know from personal
> experience that it can be expensive to design electronic hardware when your
> not an expert.

Well, it also costs a LOT to develop hardware, even if you ARE an
expert! Chips don't work the way the data sheet says the do, and you
have to call the guy who DESIGNED the chip, or the guy who built the
test rig that tests them at the factory, to get the real story. I did a
1 KW power factor corrector/inverter for a failed project. We couldn't,
at that time, get the cost in reason. But, I also had about a year of making
huge explosions in the basement, to the point that I crawled under the bench,
put on ear protectors, and plugged the thing in. If there was no concussive
detonation, with fragments pinging off the walls, then I got back up and
started probing things with a scope. (I'm not joking at all about this, I
got real gun-shy of that project when two large power transistors shot
inches past my head on either side, glowing bright yellow and leaving
smoke trails!)

> I have made mistakes and they have cost me more to fix that
> it would have cost to originally buy the pre-made boards. The worst thing
> about rolling your own some times is that you end up smoking them :-) I
> know from my abilities it is better for me to buy the electronics from an
> expert.

Any time you work with power electronics, you WILL smoke a few
parts, even if you are an expert. The experts are good enough to learn
what went wrong on the 2nd detonation, and fix it so there isn't a 3rd.
(The first one is a surprise, the 2nd has instruments placed to locate
the trouble.)


I think the fact that I've never smoked one of my 2nd generation PWM
servo amps is largely due to the huge amount of smoke produced by
the first generation! It took much more than the 2nd one to find what
was causing the problem, and I had to swap out the main chip for a
bunch of separate chips to properly solve it.

Jon