Georg,
I'm curious what the EN version of the standard looks like. I have the
IEC 61326-1 and the amendment (A1) which is dated November 14, 1997.
The amendment appears to pull 3 different environments into one
standard, whereas IEC 61326-1 appeared to be only part one of three
parts. The amendment specifically addresses three environments:
1) Industrial Locations
2) Laboratory or test equipment
3) Controlled EM environment
Each one of these environments calls out a slightly different set of
tests. For the industrial environment, which is the closest comparison
to EN 50082-2, the tests look like this (a little different than what
you wrote):
ESD:
EN61326-1 : 4kV/8kV
EM fields
EN61326-1 : 10V/m
HF conducted:
EN61326-1 : 3V
burst on AC supply (surge)
EN61326-1 : 1kV differential, 2kV common mode
EFT (all I/O):
EN61326-1 : 2kV
IEC 61326 will become EN 61326 which I believe is a product family
standard that will take precedence over the generic standard (EN 50082),
if applicable.
Now that I've confused the issue, your question was how to build
equipment to meet a standard that is more severe than the components in
it meet. I'm not sure what kind of help you need, but here are some
thoughts. I am going by the book on this one, but in Europe you have
basically two choices:
1) Do the testing and the engineering on the entire system to meet the
standards and self-declare - this may lead to I/O filters or other less
pleasant fixes.
2) TCF through a competent body - this may be a fairly reasonable
approach if the system is close to meeting the standards and you can
prove that it will work in its actual environment.
>From a pure technical standpoint, we have had some success working with
vendors getting them to make simple changes on their products to meet
higher levels of immunity. Often they are more than happy to help, but
don't know what to do. Other times they just say no. Another thing
that can be done is to approach the EMC performance from a containment
point of view. This may be your only option when you can't control the
performance of the subsystems. Look at adding shielded wires (being
careful about where and how they are terminated). Maybe you can create
some I/O terminal blocks or simple PC boards at the I/O points and place
EMC protection there. Cabinets can help a little, but at higher
frequencies seam dimension limit their effectiveness. An EMC cabinet is
an option if you're desperate, but expensive.
Hope this helps a little and good luck.....
Dave Ried
EMC engineer and punching bag
Woodward Governor Company
[email protected]
----------
From: Georg M. Dancau
To: emc-pstc discussion group
Subject: EN61326-1 vs EN50082-2
List-Post: [email protected]
Date: Wednesday, April 01, 1998 7:05PM
Dear compliance colleagues,
I just received the (german translation of) EN61326-1.
This standard applies to various classes of apparata, but also to
IPMC,i.e. industrial-process measurement and control apparata, such as
PLCs, displays, etc.
This new standard applies to apparata for INDUSTRIAL ENVIRONMENT
but requires an immunity which corresponds to EN50082-1 (domestic
environment). The requirements of the generic standard for industrial
environment, EN50082-2, are much higher.
Examples:
ESD:
EN50082-2 : 6kV/8kV
EN61326-1 : 4kV/4kV
EM fields
EN50082-2 : 10V/m
EN61326-1 : 3V/m
HF conducted:
EN50082-2 : 10V
EN61326-1 : 3V
burst on AC supply
EN50082-2 : 2kV
EN61326-1 : 1kV
The question which arises is, how to build an equipment which has to
comply with EN50082-2 using display, PLCs etc. which comply only with
these lower immunity requirements.
Even if it could be assumed that cabinets provide some attenuation for
EM fields and conducted disturbances (e.g. using filters ), displays
should
have an immunity of 6kV against ESD since they can be accessed
from "outside".
Any comments welcome.
Greetings
Georg Dancau
--
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