>From another manufacturer: There is currently a corrigendum circulating to clarify this issue, but the way it's currently written, it probably won't survive.....
Most agree the calibration should be done at the output terminals where the EFT is to be applied: direct output or through a CDN..... In either case, most also agree that the calibration should be done for each line output of the CDN, independently (one at a time) with a 50 ohm load. Otherwise you can't insure that each output is operating correctly...... When all lines are tied together, this DO change.. An alternative might be to verify that each line by itself is correct, AND that when tied together in common mode, the output is still the same, but it won't be..... Hope this helps... Michael Hopkins Manager, Customer Technical Center Process Instruments Division Thermo Fisher Scientific One Lowell Research Center Lowell, MA 01852 Tel: +1 978 275 0800 ext. 334 Fax: +1 978 275 0850 [email protected] From: [email protected] [mailto:[email protected]] On Behalf Of T.Sato Sent: Tuesday, February 06, 2007 9:17 AM To: [email protected] Subject: IEC 61000-4-4 ed.2, verification of CDNs Hello, Now, I have a question about interpretation of IEC 61000-4-4 ed.2 clause 6.2.2 about verification of CDNs. I believed that waveform at output of the CDNs must be verified for the requirements in clause 6.2.2 of the standard, by applying the pulse to all the lines simultaneously (e.g., L+N+PE), because IEC 61000-4-4 ed.2 clause 6.2.2 says The waveform shall be verified at the ***common mode output*** of the coupling/decoupling network with a single 50 ohm terminator. ... The functionality verification of each single coupling/decoupling path is recommended. and it is also the injection mode to be used for tests. However, a test equipment manufacturer told us that they verify their test generators / CDNs by applying the pulse to each of the lines one by one (i.e., L only, N only, ...) and output voltage at output of their CDNs may dropped significantly when pulse is applied to multiple lines simultaneously, and the generators / CDNs are IEC 61000-4-4 ed.2 compliant, even if the voltage at output of the CDNs are out of tolerance when applied to multiple lines. My question is, is the manufacturer's interpretation correct? Does anyone here have information related to this issue? Regards, Tom Tomonori Sato <[email protected]> URL: http://homepage3.nifty.com/tsato/ - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
