I have not heard of this exemption for the EU, but it may soon
loose it's abuse and "ignored" status in the USA.
The new self-declared FCC Class B process (effective August 1996)
was expected to allow the FCC to spend more time enforcing
compliance. That now seems to be true. The FCC recently
announced that they were sending out their people to personally
visit both retailers and manufacturers, taking along some simple
emission test equipment.
The FCC intends to perform simple RF sniffer probe measurements on
products on-site, and hand out info and possibly warnings about
the penalties and such. IMO any measurements they perform that
suggest high emissions could trigger a more rigorous FCC audit
(regardless if the product is exempted or not, remember the
"general conditions" of section 15.5 still apply). EMC-PSTC
readers may want to read the text of the FCC announcement
(somewhere) on their web page at "www.fcc.gov".
Back to the EU; CENELEC will soon be publishing EN 61326-1 (from
IEC 1326) which specifically addresses electrical equipment for
laboratory, measurement, and control. This is a total EMC
standard (features emission & immunity requirements in one handy
package) which effectively replaces the largely ignored EN 61131.
From what I've read, EN 61131 is considered an old and inadequate
EMC standard by the CBs, so the generic standards have been
substituted in practice.
Immunity standards for industrial control equipment are generally
tougher than the ITE and generic standards. This is reflected in
the forthcoming additions to EN 61326 (-10, -20...) which increase
the immunity severity levels - especially if the device is used
for industrial control. My impression is that, to date, CENELEC
considers the potential safety hazards of EMC-sensitive industrial
controllers to be an important issue.
There are some fundamental differences between how the FCC and
CENELEC view immunity issues, and sometimes even emission too. It
sounds like someone got this mixed up; I encounter this error
frequently from engineers that know just enough to be dangerous.
Regards,
Eric Lifsey
National Instruments
_______________________________________________________________________________
Subject: exemptions for industrial control equipment
From: "Jonathan Malton" <[email protected]> at Internet
List-Post: [email protected]
Date: 3/11/97 11:29 AM
Hello all.
For products destined for the US market, industrial control equipment
manufacturers can sometimes take advantage of the exemption clause of
section 15.103 of the Part 15 rules, which states that "The following
devices are subject only to the general conditions of operation ... and are
exempt from the specific technical standards ... (b) A digital device used
exclusively as an electronic control or power system utilised by a public
utility or in an industrial plant." There are other exemptions, which
might have changed since my copy of the requirements was printed.
(Someone at the FCC told me that manufacturers have taken this exemption
more often than they should, and for equipment that does not really
qualify, but that The Commission has insufficient resources to police it
closely, and that the impact of a crack-down on industrial equipment
claiming exemption but which should not really be exempt would be too
unpopular to be considered!)
I have heard a rumour that a similar exemption is permitted in the European
marketplace, with a newly-introduced exemption for dedicated industrial
control equipment. Is this part of EN61131, the programmable controller
standard? Or is it something else? Or is it just wishful thinking on my
part?
Jonathan Malton
S-S Technologies, Inc., Kitchener, Ontario.
(... but my opinions are my own, not those of my employer!)
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Subject: exemptions for industrial control equipment
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Date: Tue, 11 Mar 1997 11:29:48 -0500
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