I read in !emc-pstc that White, Ian <[email protected]> wrote (in <DE5AB3E5A2E9D6119B0F000802B2762630EB8D@UKCHEEX01>) about 'EMC retesting' on Wed, 4 Dec 2002: >Over the years l have read many articles on how to EMC test products but >none giving guidelines how often you should re-test a product once the >product has been in production for a number of years. Usually the problem >does not arise as design changes etc trigger a re-test programme. However on >some low volume products no design changes etc have occurred which in >themselves trigger a re-test. >We always try to follow a "due diligence rule" but without guidelines in the >form of case law and to my knowledge any EN standard etc, we are not sure >how to pursue this. > >Could we have your thoughts on the subject.
You are supposed to test either EVERY production unit OR enough samples, to meet the '80-80 rule' requirements. These tests need not be done according to the standards, and are usually done by comparison with a 'known good' unit that HAS been tested to the standards. The general principle of testing frequency is quite well established. You start by testing at an arbitrary frequency, such as once a week. If you find no problems, you test less often. If you find problems, you test more often. You carry on like this as a running procedure. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Interested in professional sound reinforcement and distribution? Then go to http://www.isce.org.uk PLEASE do NOT copy news posts to me by E-MAIL! ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
