I also find this to be a constant irritant in standards. From my old (very old) days in machining, I’ve used the definition of plus or minus one half the least significant digit of the measurement. Bummer for “3 meter” radiated emissions measurements!
Brent DeWitt Westborough, MA From: Price, Edward [mailto:ed.pr...@cubic.com] Sent: Tuesday, March 31, 2009 4:35 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] 10cm above GRP requirement for 61000-4-6 ________________________________ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Bob Richards Sent: Tuesday, March 31, 2009 1:10 PM To: emc-p...@ieee.org Subject: 10cm above GRP requirement for 61000-4-6 Fellow EMCers, 61000-4-6 says that the EUT must be 10cm above the GRP. There is no tolerance. However, anyone that has worked in a machine shop or in metrology knows that there is no such thing as "no tolerance". What would be considered an acceptable tolerance for the 10cm requirement? If an auditor says that the support for the EUT has to be exactly 10cm, "no tolerance", how can one argue with them that 1mm is not going to affect the test? The EFT standard, 61000-4-4, says 10cm +/- 1cm. Could this be used as a basis for an argument? Bob Richards, NCT Bob: FWIW, MIL-STD-461, which has been around longer than 61000 (and thus was probably the inspiration for "10 cm"), says, in Paragraph 4.3.1., "Unless otherwise stated...tolerance shall be... Distance: +/- 5%" Ed Price ed.pr...@cubic.com <blocked::mailto:ed.pr...@cubic.com> WB6WSN NARTE Certified EMC Engineer Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 Military & Avionics EMC Is Our Specialty - 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 <emc-p...@ieee.org> 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 <emcp...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com> - 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 <emc-p...@ieee.org> 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 <emcp...@ptcnh.net> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
