All the test labs I have used have a qualifier that the results are only for
the specimen/s submitted.
As the manufacturer, I provide the rational to include in the test report for
the configuration/s submitted.
For about 4 decades, a minimum and a maximum configs have sufficed.
ps. If the marketing model number changes for various configs, that generally
gets a some degree of testing with notes added to test report to explain the
differences and commonalities, and the front page gets modified that the test
report covers these additional models.
On Friday, April 12, 2024, 2:59:06 PM EDT, Lauren Crane
<[email protected]> wrote:
I think one could postulate a worst case hardware/software combination, but it
would have to be well defended in text along the lines of “no other
configuration could be worst case because…” followed by a discussion of the
physical aspects of the other configurations and what they imply, based on
‘first principles’, regarding emissions and susceptibility. Even then, if there
are many configurations (e.g., more than 5?), it would be wise to test a one or
two for which your written hypothesis might be less certain.
The EMCD guidelines (19 Dec 2018) seem to me to be accepting of this idea…
- “The EMC assessment needs to take into account all normal intended
operating conditions of the apparatus. In cases where the apparatus can take
different configurations, the electromagnetic compatibility assessment must
confirm that the apparatus meets the essential requirements, “in all possible
configurations identified by the manufacturer as representative of its intended
use”[quoting Annex II.2]”.
- “Where apparatus can take different configurations, the EMC assessment
shall confirm that the apparatus meets the essential requirements in all of the
configurations foreseeable by the manufacturer as representative of normal use
in intended applications.The manufacturer is responsible for identifying the
possible configurations and the choice of the worst case(s). The use of the
worst case approach needs to be documented in the technical documentation”[35].
[35]=” Within the immunity and emission phenomena to be covered, different
worst case selections may occur (because of non-related phenomena). This may
increase the number of cases to be investigated “
Note particularly - the guide highlights the obligation of deciding worst case
is placed on the manufacturer. If you provide them some guidance but remind
them the decision of testing fewer or more of the configurations rests with
them, they may have a softer attitude towards more testing.
Best regards,
-Lauren
Confidential – Limited Access and Use
From: Bill Owsley <[email protected]>
Sent: Friday, April 12, 2024 1:19 PM
To: [email protected]
Subject: Re: [PSES] I would like to hear your thoughts please
|
|
External Email: Do NOT reply, click on links, or open attachmentsunless you
recognize the sender and know the content is safe. If you believe this email
may be unsafe, please click on the “Report Phishing” button on the top right of
Outlook.
|
The usual response is that it depends...
More 'light' reading ! To start !
https://www.fcc.gov/sites/default/files/32-KDB-996369-Modules-TCB_Oct_2023.pdf
On Wednesday, April 10, 2024, 5:22:12 PM EDT, Lfresearch
<[email protected]> wrote:
Sorry for the late reply, but I did feel the need to express strong
disagreement with some statements here.
Lets take there first one: how will you know which is worst case if you don’t
test. Seriously? I would answer this by saying that an EMC engineer with any
proficiency can make an educated decision as to what would be the worst case,
further, if one can’t do that you shouldn’t probably be in EMC Engineering. Is
the old saying from school days “ You should have an idea of the answer before
doing the problem “ no longer stressed in school!
The back reference to Boeing is utter BS, sorry Gert, but as someone who
contracts for Boeing I take a very strong exception to that ridiculous
statement. There is absolutely NO correlation between a poor quality
subcontractor and the EMC performance of an EUT. It may be true for airbus, but
leave my Boeing alone please.
Back to the problem at hand, and serious answers only please.
At what point(s) does one draw the line eliminating the need for testing
similar designs.
Thanks in advance,
Derek Walton.
On Apr 6, 2024, at 7:55 AM, Gert Gremmen F4LDP <[email protected]> wrote:
Dear All,
Within the framework of the EMCD, all configurations shall be conform, so if
you choose to actually test,
all configurations shall be part of the test. The subject of worse case is a
"miroir d'alouette"... how will you ever know which
is worst case without carrying out the test ? A pre-scan is informative but the
radiated emission test contains already a pre-scan (peak) for the final
QP-measurement. We already require a EMC risk analysis which is a kind of
pre-scan too. How many pre-pre-prescans will we need to be sure ?
"to repeat some (which?) test to make sure nothing was broken".... it's another
discipline, but that is how Boeing lost a door in flight. And that is not a
unregulated sector without thorough quality scans (understatement), and still
it happens. Imagine the costs and effort for Boeing to rebuild their reputation
? Didn't we all learned the exponential graph of EMC costs versus development
time ?
If you need proof (for authorities, or for yourself), nothing can replace the
actual test.
Gert Gremmen
On 6-4-2024 0:47, Lfresearch wrote:
Hi folks, I would like to advise a client at where to draw the line on what
needs testing. I would like to solicit opinions besides my own. Otherwise it’s
the fox urging the chicken coop… So a manufacturer that makes a product of
which there will be several variants. All use the same board, but have
different sections of circuits populated. This may require slightly different
code to run on the same uP in each case. So.. The burning question is can we
perform and analysis that postulates a worse case hardware/software combination
and test just one configuration? Or, do we have to do every combination? Or,
are there some guidelines about where we draw the line of what to test and what
can be claimed as similarity? Off list responses are welcome too. Thanks,
Derek Walton LFResearch/SSCLabs. -
---------------------------------------------------------------- This message
is from the IEEE Product Safety Engineering Society emc-pstc discussion list.
To post a message to the list, send your e-mail to [email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/ Website:
https://ewh.ieee.org/soc/pses/ Instructions:
https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List
rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to
the list administrators: Mike Sherman at: [email protected] Rick Linford
at: [email protected] For policy questions, send mail to: Jim Bacher:
<[email protected]> _________________________________________________ To
unsubscribe from the EMC-PSTC list, click the following link:
https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
-- Independent Expert on CE marking EMC Consultant Electrical Safety
Consultant
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail
[email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/
Website:https://ewh.ieee.org/soc/pses/
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to
unsubscribe)
List rules: https://ewh.ieee.org/soc/pses/listrules.html
For help, send mail to the list administrators:
Mike Sherman at: [email protected]
Rick Linford at: [email protected]
For policy questions, send mail to:
Jim Bacher at: [email protected]
To unsubscribe from the EMC-PSTC list, click the following
link:https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail
[email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/
Website:https://ewh.ieee.org/soc/pses/
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to
unsubscribe)
List rules: https://ewh.ieee.org/soc/pses/listrules.html
For help, send mail to the list administrators:
Mike Sherman at: [email protected]
Rick Linford at: [email protected]
For policy questions, send mail to:
Jim Bacher at: [email protected]
To unsubscribe from the EMC-PSTC list, click the following
link:https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail
[email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/
Website: https://ewh.ieee.org/soc/pses/
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to
unsubscribe)
List rules: https://ewh.ieee.org/soc/pses/listrules.html
For help, send mail to the list administrators:
Mike Sherman at: [email protected]
Rick Linford at: [email protected]
For policy questions, send mail to:
Jim Bacher at: [email protected]
To unsubscribe from the EMC-PSTC list, click the following link:
https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
LAM RESEARCH CONFIDENTIALITY NOTICE: This e-mail transmission, and any
documents, files, or previous e-mail messages attached to it, (collectively,
"E-mail Transmission") may be subject to one or more of the following based on
the associated sensitivity level: E-mail Transmission (i) contains confidential
information, (ii) is prohibited from distribution outside of Lam, and/or (iii)
is intended solely for and restricted to the specified recipient(s). If you are
not the intended recipient, or a person responsible for delivering it to the
intended recipient, you are hereby notified that any disclosure, copying,
distribution or use of any of the information contained in or attached to this
message is STRICTLY PROHIBITED. If you have received this transmission in
error, please immediately notify the sender and destroy the original
transmission and its attachments without reading them or saving them to disk.
Thank you.
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
[email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/
Website: https://ewh.ieee.org/soc/pses/
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to
unsubscribe)
List rules: https://ewh.ieee.org/soc/pses/listrules.html
For help, send mail to the list administrators:
Mike Sherman at: [email protected]
Rick Linford at: [email protected]
For policy questions, send mail to:
Jim Bacher at: [email protected]
To unsubscribe from the EMC-PSTC list, click the following link:
https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
-
----------------------------------------------------------------
This message is from the IEEE Product Safety Engineering Society emc-pstc
discussion list. To post a message to the list, send your e-mail to
[email protected]
All emc-pstc postings are archived and searchable on the web at:
https://www.mail-archive.com/[email protected]/
Website: https://ewh.ieee.org/soc/pses/
Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to
unsubscribe)
List rules: https://ewh.ieee.org/soc/pses/listrules.html
For help, send mail to the list administrators:
Mike Sherman at: [email protected]
Rick Linford at: [email protected]
For policy questions, send mail to:
Jim Bacher: <[email protected]>
_________________________________________________
To unsubscribe from the EMC-PSTC list, click the following link:
https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
