RE: my request of a couple of weeks ago for EMC compliance horror stories:
Thanks to all who shared humorous and real horror stories. I have shared most of them with my management. While the stories of good intentioned designs gone bad were helpful, I just wish I had more accounts of manufacturers/integrators getting into legal difficulties over non-compliance with EMC rules. Jim Knighten ------------------------------------------------------------------------ --------------------------- Dr. Jim Knighten NCR 17095 Via del Campo San Diego, CA 92127 Telephone: 619-485-2537 Fax: 619-485-3788 e-mail: [email protected] ---------- From: [email protected] [SMTP:[email protected]] Sent: Wednesday, July 15, 1998 4:37 PM To: 'emc-pstc list server' Subject: RE: Looking for Horror Stories ------------------------ From: "Grasso, Charles (Chaz)" <[email protected]> Subject: RE: Looking for Horror Stories Date: Wed, 15 Jul 1998 12:54:13 -0600 To: 'emc-pstc list server' <[email protected]>, "'Knighten, Jim'" <[email protected]>, "'WOODS, RICHARD'" <[email protected]> Cc: "'[email protected]'" <[email protected]> > You will have to go back a number of years to find the first > non-EMEmissions standard. As I recall, the first EME standard was > actually VDE 0871 and the German government was concerned > primarily with emissions interfering with legitimate communication. > Largely as a result of that CBEMA released a document that finally > became > FCC CFR47 Part 15. And so an industry was born. > > > Thank you > Charles Grasso > EMC Engineer > StorageTek It would be interesting to know when the first VDE commercial emission standard was published. However, I know that the FCC Part 15 and Part 18 emission requirements were in place as early as 1968. I started out doing field measurements for Part 18 industrial stuff (like RF welding and RF industrial process equipment). I still have very vivid memories of measuring "field strength at a 1000 foot radius on each of 18 radials" and "at 1 mile on the strongest radial", whether in the middle of a cornfield or the edge of a river. I also did Part 15 CE and RE testing, and sometimes a manufacturer used the same FCC data and compared it to the existing VDE spec limits. It was my understanding that the FCC and VDE conducted emission protocol was based on the Military Mil-I-6181 spec (in which there was a design note on the construction of a 5 uH LISN). The use of an LISN traces back to a US Army Air Force WWII study on a medium bomber power bus interference. I don't have much factual basis, but my guess is that German regulatory activities suffered a bit of a discontinuity circa 1945, and that, by the time VDE got its first new issue of pencils, they decided to use the existing FCC and US Mil precedents. If I've been around since before the industry was born, does that place me among the undead? But, having been certified that I'm not a competent body, whadda I know? Ed -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 Date: 07/15/1998 Time: 15:36:45 --------------------------
