What we call, Production Audit testing, should be done at intervals necessary to insure compliance. This interval is dependent on the product, and the likelihood of variations in the production process and how likely those variations can affect compliance.
Our products are very low volume (maybe 50-200 per year per product family) and are built to order. They are not built on an assembly line where thousands of identical products are built per run. To insure compliance, we audit each family of products at least once a year. Other companies run tens of thousands of products on automated assembly lines where the first product in a run is identical to the last. These runs can be assembled over a few days to a few years without production audit. Personally, I would like to see more details called out somewhere for mandatory re-sampling/retesting/audits of production products. Currently it seems every company does it different. Recently we had several Surge Immunity failures with a specific model of power supply. We requested the latest test data from the manufacturer and they sent us a test report from 1996. They said their policy is never to audit or retest for compliance unless the product goes through a major redesign. Though very sad, many component manufacturers follow this same practice. Because of this, we (system manufacturer) have to increase our retesting/audit practices. You would think with all the Test Lab representatives who sit on Standards Writing Committees there would be an audit standard or at least some mention of it is every test standard. The 80/80 rule in Emissions standards is almost never followed to the letter or to its intent. Most companies get their Golden Unit to pass and production units are never verified. Very sad. For those of you who do a good job of testing and auditing your production products, I tip my hat to you. I want to buy products from companies like yours. Hope this was helpful. The Other Brian ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Pickard, Ron Sent: Friday, April 10, 2009 10:37 AM To: [email protected] Subject: RE: Equipment in series, now time to time And, while we're on the subject of CISPR 22:2006 Section 7, in 7.2.1.2 regarding ransom sampling/retesting, what is meant by "...from time to time..."? As this is so nebulous, how can it be quantified, or can it? I look forward to your reply. Best regards, Ron Pickard [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of John Woodgate Sent: Friday, April 10, 2009 9:06 AM To: [email protected] Subject: Re: Equipment in series In message <of8042504d.0de90ed8-on86257594.0048b0bc-86257594.0048d...@mmm.com>, dated Fri, 10 Apr 2009, [email protected] writes: >Thanks.............what does S represent in the formulas in 7.2.3 of EN >55022:2006? It's S_n, and it's the 'sample standard deviation', as opposed to the 'population standard deviation', which has 1/n instead of 1/(n-1) in the second equation in 7.2.3. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html 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]> _________________________ LECO Corporation Notice: This communication may contain confidential information intended for the named recipient(s) only. If you received this by mistake, please destroy it and notify us of the error. 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 http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html 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]> - 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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html 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]>
