I have only peripherally been aware of this thread, but reading these last two posts makes me wonder why you don¹t have some sheet metal you can punch to your heart¹s content, but the sheet metal always connects to the floor beneath it the exact same away. Same concept as a bulkhead plate that can be punched out uniquely for each individual test set of connectors, but the bulkhead plate connection to the chamber is the same set of holes and fasteners.
Ken Javor Phone: (256) 650-5261 From: John Woodgate <j...@woodjohn.uk> Reply-To: John Woodgate <j...@woodjohn.uk> Date: Sat, 10 Aug 2019 12:18:51 +0100 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Conducted emissions AMN/AAN layout I endorse paragraph 2 below. We in GB are lucky that participation in standards work in BSI is free. (But it doesn't stop us complaining about the cost of BSI standards - a doozy I found yesterday is £200 for six pages, of which three are the actual text.) Standards work is to a significant extent supported by people who, for whatever reason, have more than normal time to devote to it. Quite a large proportion are formally retired, and for them, continued participation is not only 'making a difference' but also essential intellectual exercise. Makers of AMNs and the like might address this issue by devising other ways of attaching the boxes to the ground plane without using holes. For example, if there is a sheet of steel under the ground plane. magnets on the boxes would work. Best wishes John Woodgate OOO-Own Opinions Only J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> Rayleigh, Essex UK On 2019-08-10 10:37, Gert Gremmen wrote: > > > Drilling holes in (new) chamber is like drilling holes in your new cars roof > for an antenna. I can imagine your hesitation. However there is (as long as > the holes are not to big and correctly made) nothing against it. If it allows > you to reliably position your AMN devices you need, a swiss cheese will be > the best solution. > > > Regarding the standards... standards are written by guys like you and me. > Experts in the WG and national committees are not paid for their knowledge > (which actually is one of the finest on the planet !) , and many of them will > confirm that they (or their employer) actually need to pay to transfer their > expertise to IEC. Many members will lack motivation (or are not allowed ) to > really spend time in correcting, drafting and searching for problems in > standards texts. Participating in standards work is a kind of charity, but for > those who are nominated to defend their employers interests. So small errors > are easily overlooked, and it seems that you found a few of them. > > > Please do not worry and find your own (defendable) solutions, experiment and > verify if measurement differences occur. There will be. EMC testing is not an > exact science and standards are should be read as a generic guideline. No-one > will notice the differences in set-up and no-one will challenge them as their > own experience will be similar. If your are to be audited, referring to the > open issues in the standard might help. > > > > Cable lay-out is the most difficult part of emission testing, and small > difference will make sometimes 10's of dB of differences. Where the equipment > set up and the room calibration will give you a measurement uncertainty (MU) > of about 5 dB (if all done right) the EUT setup will easily add 15-20 dB to > that. > > > > Oh and if you are interested into a better test set-up than CISPR32 (former > 22), look into the CISPR 16 series,especially the chapters om measurement > volumes. > > > > > > > > Gert Gremmen > > > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
