LINK LOSS Complete link loss is likely from the collision-detect circuitry (EUT or AE); it interprets the induced RF + signal as a collision. Hubs typically 'partition' ports having high collision rates (remaining ports function normally if the noisy node is disconnected). Some hubs 'unpartition' a noisy port if it is quiet for several minutes. In my opinion, a partitioned port is a failure.
BIT ERROR Ethernet is designed for a 1E-10 to 1E-14 bit-error-rate environment. Higher rates clog the network with resent packets. See M. Shooman, "The Reliability of Error Correcting Code Implementations." Proc RAMS:1996. IEEE, p148,ff. IEC61000-4-6 acceptance criteria do not require theoretical bit-error rates during screening. Consider your customer: evaluate competitive product and set your goal at equal or better performance. TEST VALIDITY In light of the above, it is important that the immunity test configuration be close to real world. 1) Preserve the IEEE802.3 transmission line - avoid short cables (especially with F-E) and do not attach probes to the line (possible antenna) 2) Cat-5 is required for Ethernet/F-E; 10/100 should also be tested at 10Mb on Cat-3 3) 'band-aid' fixes for EN55022 can reduce immunity; ferrited RJ-45's increase back pressure causing cable-length sensitivites (very bad - customer complaints - no fault found). 4) Field strength is high near the RF input end of the EM clamp. Keep unrelated AE cables away from this area; >300mm clamp-EUT separationmay be required (which you should note on the data sheet). TECHNICAL A good starting point is Application Note 8.7 by T. Greene and P. Brandt on SMSC's website http://www.smsc.com David ----Original Message----- From: Chris Maxwell [mailto:chris.maxw...@nettest.com] Sent: Friday, April 19, 2002 1:35 PM To: emc-p...@majordomo.ieee.org Subject: RE: Suitable CDN for IEC61000-4-6 ethernet 10/100 Maybe there's the rub. We have usually tried to test a device to device link using a crossover cable. We haven't had to worry about small errors. I considered a link loss to be failure; and that's what I was seeing...a complete link loss. Perhaps using a bridge or other type of LAN driving device would make our Ethernet link seem more robust during the test. What do you mean by a "lxia" box? Chris > -----Original Message----- > From: Gary McInturff [SMTP:gary.mcintu...@worldwidepackets.com] > Sent: Friday, April 19, 2002 1:18 PM > To: Pommerenke, David; Chris Maxwell; emc-p...@majordomo.ieee.org > Subject: RE: Suitable CDN for IEC61000-4-6 ethernet 10/100 > > Yup, when we do immunity testing - we see the occassional crc > error or the ilk, but I've never seen a problem with the link. We use > an Ixia box to cram data down the lines. There are probably many other > traffic generators that will work just fine but none of them are > pocket change. > Gary > > -----Original Message----- > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
