Performance criteria is one of the hardest things to handle when doing the generic immunity evaluations. The standard is extremely vague, and does open the manufacturer to essentially define his own criteria.
EN 50082-x does, however, put caveats on Category B, which causes the
most consternation. That is, "No change of operating state, or loss of
stored data is allowed.". That prevents the mfg. from saying that the
device is allowed to shut off and then restart (e.g.-in the case of a
PC). The primary consideration is what the ultimate customer expects.
If he doesn't care that his PC reboots every time it gets hit by ESD,
then there is no problem!
That is where documenting the criteria in the test report becomes
significant. Some reports simply plagiarize the text in EN 50082 to
define the performance criteria. The reports should contain enough
detail on the specific product performance to clarify acceptable
performance. Each criterion (A, B, C) should be specifically spelled
out in the report, so that it is clear what assumptions were made.
Defining these details before the testing is started makes the testing
process go much smoother as well. There is no question (or the
corresponding delays $$$$) while trying to 'weasel out' of a
potential non-compliance, if it is clear what is expected of the
product.
Bob Martin
Sr. Technical Manager
Intertek Testing Services
(978)263-2662
fax (978)263-7086
r...@itsqs.com
-----Original Message-----
From: plaw...@west.net [SMTP:plaw...@west.net]
Sent: Friday, September 04, 1998 12:16 PM
To: emc-p...@majordomo.ieee.org
Cc: Jim Hulbert
Subject: Re: Re[2]: Inconsistency of EN 50082-1 with 1000-4 series
On Fri, 04 Sep 98 09:18:30 -0500, you wrote:
>What bothers me about the criteria in EN 50082-1 is the provision for
the
>manufacturer to define the permissible loss of performance. This
opens the door
>for the manufacturer to simply relax the product specification to
"pass" the
>test. Luckily, our EMC group generally inputs the EMC requirements
into our
>product specifications so that we have the opportunity to define
reasonable
>performance criteria.
I thought that was a bit strange at first, too.
However, the Test Report should describe the test conditions, test
results, and
interpretation of the results. The IEC1000-4 testing standards have a
section
discussing the test report, and the subject is also discussed in BS
EN
50082-1:1992 'Performance Criteria':
"A functional description and a definition of performance criteria,
during or
as a consequence of the EMC testing, shall be provided by the
manufacturer and
noted in the test report, based on the following criteria:"
(performance criteria details follow)
In a similar manner, if a manufacturer claimed a product met a
specific safety
specification, I would want documentation that supported the claim.
The same
is true for EMC immunity.
<snip>
--
Patrick Lawler
plaw...@west.net
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