Searching around for a "dead" test lab (in the sense that
it seems every emission is lower) is safer to do than
simply lying that you have a test report verifying
compliance. At least, they do have a test report on file.
Didn't know were so aggressive in Europe.
Given the two processes starting at the same time, yes, I
think it is easier to design the product to meet compliance
than it is to "properly" design the product. After all, a
properly designed product will always meet or exceed spec,
even outside ranges of operation, is manufactured with junk
components, and lasts forever.
I remember how difficult aerospace design was. It's very
difficult to design flight control systems that continue to
meet spec when a single component fails *and* tells you
about it, and if another component fails it tells you that
also, then nulls out the control system so you don't fly
into the ground at 600 mph. Simply designing a product
that has satisfactory performance was not an option, we
used to call that "garage design".
Well, it is true in the larger scope of things I don't have
a lot of experience with compliance and testing, only been
involved with it since 1966. But it does help to have a
heavy analog design background, including low noise,
magnetics, high voltage, and microwave.
To me, anyway, it's that EMC is like a being critic, you
have something to work on. Product design, is like
creating from nothing.
Now doing "after the fact" EMC, THAT's ANOTHER STORY!
- Robert -
On Tue, 19 Jul 2005 06:40:45 +0100
John Woodgate <[email protected]> wrote:
> Robert A. Macy <[email protected]> wrote (in
> <[email protected]>) about 'EMC Ethics', on
> Mon, 18 Jul 2005:
>
> >One of my EX-Clients rather than fixing the problem
> would "shop" test labs. The client compared results from
> each lab and found a "dead" test lab and used it to get
> passing data.
>
> I doubt you could do that in UK or Germany; the
> surveillance from the accreditation services is far too
> aggressive.
> >
> >I've always told my clients that not passing with good
> margin merely points out that the design is "out of
> control".
>
> There are some situations where the test results are
> inherently wildly variable for well-understood reasons.
> An example is the mains harmonic emissions from
> single-phase rectifiers with capacitive filters.
>
> > Geesh! If you can't even control a smple thing like
> emissions and
> >susceptibility what's the warrantee costs and marginal
> performance
> >going to be like?
>
> I'm glad you think that emission and immunity control is
> simpler than ensuring satisfactory performance. I think
> much experience suggests the contrary, IF the
> design-for-performance process is itself under control -
> no 'cut-and-try'.
> --
> Regards, John Woodgate, OOO - Own Opinions Only.
> Deadlines are 90% of deadliness.
> http://www.jmwa.demon.co.uk Also see
> http://www.isce.org.uk
>
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