Hi Doug, Assuming both labs are qualified as you say, you also make the assumption that the 2nd lab has full knowledge about the setup of the EUT. And that's exactly the problem. That 2nd lab doesn't know and thus results may be different, even fail, due to the relative positions of the EUT and all its cabling, sending other kind of traffic, etc.... If the 2nd lab has the report of the first, then results would be more or less the same.
Best regards, Kris Carpentier From: Doug Powell [mailto:[email protected]] Sent: vrijdag 5 september 2014 17:26 To: [email protected] Subject: Re: [PSES] Failure of Radiated emission Kris, The test standards describe a standardized setup of the environmental conditions, the test equipment, the field calibrations and the UUT, all described in enough detail to be able to duplicate the setup at a later time. This is supposed to ensure that testing at another qualified lab, following the same rules, gets similar results. I have had customers attempt ad hoc setups in an uncontrolled factory environment, which failed miserably (often poor grounding). Usually an explanation about the level of rigor involved is enough. If not, it should be explained that for customers performing in situ evaluations they should be concerned about non-interference rather than getting below a certain limit. Opinions only, ~ Doug On Fri, Sep 5, 2014 at 9:09 AM, Macy <[email protected]<mailto:[email protected]>> wrote: It is my understanding that what you say is correct. From memory, PROVING something complies is different than VERIFYING something complies. For example, as a customer, or a monitoring entity, when 'verifying'; you are allowed a single tone over the limit, because statistically that can just happen. BUT if you are PROVING compliance and using a single unit, you should have at least 2.6dB margin to the limit. And testing 3 units, be less than the limit. Isn't that from the VDE standards years ago? --- [email protected]<mailto:[email protected]> wrote: From: Carpentier Kristiaan <[email protected]<mailto:[email protected]>> To: [email protected]<mailto:[email protected]> Subject: [PSES] Failure of Radiated emission Date: Fri, 5 Sep 2014 14:35:44 +0000 Hi group, A ITE product is tested to EN55022 Radiated emission with a well defined setup (cables, traffic, etc...) trying to find the worst case emissions and it passes. I think finding the real worst case emission for all frequencies with one and the same set-up is in practice not possible in practice. That same product is retested by a customer or in case of market surveillance campaigns, then it is most likely not tested with the same set-up and results may fail. Would this be an issue or is it acceptable that it is retested with the same set-up as the initial testing? I refer to CISPR22, clause 8.4 that states that the operational conditions of the EUT shall be determined acc. to typical use.....The operat mode and rationale shall be stated in the report. So to me it looks sufficient to test a typical set-up, do your best to not make it best case and describe everything in the report. Any other thoughts? Best regards, Kris Carpentier - ---------------------------------------------------------------- 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]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher: <[email protected]<mailto:[email protected]>> David Heald: <[email protected]<mailto:[email protected]>> -- Douglas E Powell [email protected]<mailto:[email protected]> Skype: doug.powell52 http://www.linkedin.com/in/dougp01 - ---------------------------------------------------------------- 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]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- 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: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
