RE: An ESD question
Remember at time testing at a manufacturing location down south. Don't know if it was humidity but we were the first to know that a rain storm was headed our way. There was a dramatic change in the ESD discharge and response characteristics before and during the downpour. Same for a trip in Japan - which is very humid to start with. No attempt to explain - just presenting a couple of experiences. Wasn't really an obstacle, we were easily able to locate and resolve the problem regardless of the outside weather. PS neither of the locations had air conducting or humidity control so other than physical raindrops we had the same temperature and humidity as outdoors. I dawns on me, that to work out the variability in weather in Japan we moved into their sound chamber, that for some reason did have humidity control - not a clue why. Gary -Original Message- From: bogdan matoga [mailto:bogda...@pacbell.net] Sent: Wednesday, June 12, 2002 12:01 PM To: Gibling, Vic Cc: emc-p...@majordomo.ieee.org Subject: Re: An ESD question Vic: The ambient relative humidity should have no impact on the performance of the gut but only on the generation of static charges. So, to improve the performance in the field, I would suggest that you increase the R.H. at the customer site(s) to about 50% which would eliminate the generation of electrostatic charges and consequently the problems. This will give you time to work on the equipment to minimize ESD susceptibility. By the way, lower R.H. also occurs at low tamperatures. Please let me know how things work out. Bogdan. Gibling, Vic wrote: > Dear Group > > I tried to find David Pommerenke article's in the Journal of ESD on the Web > but alas no downloadable version was found, so may I ask the group a > question? > > We have an ESD field failure which is occurring in dry hot countries ( no > surprise )which can be recreated with an ESD of -800V. In an attempt to get > a high incidence of discharges we used a dehumidifier to create a dry > environment. The result was a reduction in discharges. > > Thinking the problem through -now- as a dry atmosphere will encourage the > production of high level ESD and a humid environment inhibits the charge to > a lesser level, presumably because it 'leaks' away. Then is it wrong for us > to attempt to 'dry' the local atmosphere in the hope of gaining consistent > ESD from an ESD gun, that is to say the more humid the environment the more > efficiently the discharge will transfer to the victim? > > Incidentally, to add to the thread regarding intermediate level testing for > ESD and EFT. This exercise has revealed different failure mechanisms at > different ESD levels. > > Your views would be appreciated. > > Vic Gibling > Compliance Engineer > Marconi Applied Technologies > > > > --- > 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" --- 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" --- 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 Bache
AW: An ESD question
Dear Group, In dry conditions, not only the charging processes are enhancec, but the severity (less risetime, higher peak current) is enhanced in general. For both reasons, it is not uncommen to see ESD problems move around the world with the local seasons. Still, I would always try to debug the problem in contact mode. The effect on humidity on the electromagnetic properties is in general very small. Aim of the debugging should be to identify the traces, nets of PINs that are effected. Locally injecting pulses via direct, capacitive, inductive or differential injection has prooved to be an effective tool for achieving this. David -Ursprüngliche Nachricht- Von:Gibling, Vic [mailto:vic.gibl...@marconi.com] Gesendet: Mi 12.06.2002 02:26 An: emc-p...@majordomo.ieee.org Cc: Betreff:An ESD question Dear Group I tried to find David Pommerenke article's in the Journal of ESD on the Web but alas no downloadable version was found, so may I ask the group a question? We have an ESD field failure which is occurring in dry hot countries ( no surprise )which can be recreated with an ESD of -800V. In an attempt to get a high incidence of discharges we used a dehumidifier to create a dry environment. The result was a reduction in discharges. Thinking the problem through -now- as a dry atmosphere will encourage the production of high level ESD and a humid environment inhibits the charge to a lesser level, presumably because it 'leaks' away. Then is it wrong for us to attempt to 'dry' the local atmosphere in the hope of gaining consistent ESD from an ESD gun, that is to say the more humid the environment the more efficiently the discharge will transfer to the victim? Incidentally, to add to the thread regarding intermediate level testing for ESD and EFT. This exercise has revealed different failure mechanisms at different ESD levels. Your views would be appreciated. Vic Gibling Compliance Engineer Marconi Applied Technologies --- 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" --- 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"
RE: An ESD question
Fred, et al Vic's original question asked about test conditions; and that is what the responses dealt with. As a matter of fact, the responses were very focused on the question that was asked. In the original question, I saw no discussion of the desired compliance level. For all I know, Vic could be testing a bare chip or integrated circuit for which a compliance level of 1000V could be sufficient.The come-back which I received, below, assumes that Vic needs the 4KV, 8KV or higher compliance levels typical of most complete products. That may be true; and I think that you bring up an important point that engineers need to focus on proper ESD design as well as ESD testing. So, I consider your message to be worthwhile; even while I consider the criticism in its first sentence to be off target. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | > -Original Message- > From: Fred Townsend [SMTP:f...@poasana.com] > Sent: Wednesday, June 12, 2002 12:27 PM > To: Chris Maxwell > Cc: Gibling, Vic; emc-p...@majordomo.ieee.org > Subject: Re: An ESD question > > > It is interesting to see how easy it is to lose focus. The problem is not > the humidity, approach speed, etc. as Richard has suggested. Yes, they are > factors but not the problem. The problem is a massive design flaw. 800 volts > is way too low. The fact there are multiple failure modes supports the > conclusion something major is wrong. The designers needs to review their ESD > suppression and grounding of this product. You may need to call in an ESD or > SI expert. This product is not ready for prime time. > > This discussion would be relevant if we were trying to sneak through a > product that passed at 4 KV but failed at 5 KV but not at 0.8KV. > > Fred Townsend > --- 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"
Re: An ESD question
Vic: The ambient relative humidity should have no impact on the performance of the gut but only on the generation of static charges. So, to improve the performance in the field, I would suggest that you increase the R.H. at the customer site(s) to about 50% which would eliminate the generation of electrostatic charges and consequently the problems. This will give you time to work on the equipment to minimize ESD susceptibility. By the way, lower R.H. also occurs at low tamperatures. Please let me know how things work out. Bogdan. Gibling, Vic wrote: > Dear Group > > I tried to find David Pommerenke article's in the Journal of ESD on the Web > but alas no downloadable version was found, so may I ask the group a > question? > > We have an ESD field failure which is occurring in dry hot countries ( no > surprise )which can be recreated with an ESD of -800V. In an attempt to get > a high incidence of discharges we used a dehumidifier to create a dry > environment. The result was a reduction in discharges. > > Thinking the problem through -now- as a dry atmosphere will encourage the > production of high level ESD and a humid environment inhibits the charge to > a lesser level, presumably because it 'leaks' away. Then is it wrong for us > to attempt to 'dry' the local atmosphere in the hope of gaining consistent > ESD from an ESD gun, that is to say the more humid the environment the more > efficiently the discharge will transfer to the victim? > > Incidentally, to add to the thread regarding intermediate level testing for > ESD and EFT. This exercise has revealed different failure mechanisms at > different ESD levels. > > Your views would be appreciated. > > Vic Gibling > Compliance Engineer > Marconi Applied Technologies > > > > --- > 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" --- 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"
Re: An ESD question
It is interesting to see how easy it is to lose focus. The problem is not the humidity, approach speed, etc. as Richard has suggested. Yes, they are factors but not the problem. The problem is a massive design flaw. 800 volts is way too low. The fact there are multiple failure modes supports the conclusion something major is wrong. The designers needs to review their ESD suppression and grounding of this product. You may need to call in an ESD or SI expert. This product is not ready for prime time. This discussion would be relevant if we were trying to sneak through a product that passed at 4 KV but failed at 5 KV but not at 0.8KV. Fred Townsend Chris Maxwell wrote: > Vic, > > I agree, your product is probably seeing field failures because of the dry > conditions. These dry conditions make the probability of an ESD event > higher. This is due to the fact that, as personnel walk across carpets or > rub their clothing on chairs, there is no humidity in the air to help bleed > and equalize charge. So, they have a higher probability of charging up and a > higher probability of discharging to your equipment. (You probably already > know this.) > > Of course, your problems may not be due to people discharging to your > equipment. It could be due to some other source of ESD. It could be a > discharge from a nearby object. However, the same argument holds. The dry > atmosphere increases the probability. (Hence the static cling present in > clothes that come out of a dryer.) > > So, in both cases, you are probably seeing more failures in a dry atmosphere > because the probability of an ESD event is higher. Higher failure rates in > dry atmospheres are due to this probability increase. The higher failure > rate is probably not due to a dry atmosphere ESD event being different from a > humid atmosphere ESD event. > > For testing, you are already generating the ESD event with a simulator. The > ESD generator takes probability out of the equation. You can generate a > discharge whenever you want. So, in my humble opinion you don't need to > simulate the dry conditions. I would simply follow IEC 1000-4-2, which > recommends test conditions with a humidity level between 30% and 60%. With > this combination of ESD generator and humidity, you should get a discharge > whenever you want; and it should couple to the victim in proper fashion. > > I agree that you will see different performance at different levels. I have > seen failures at 4KV air discharge that are not repeatable with 8KV air > discharge. So it is worth the time to test at lower levels until you get up > to the compliance level that you are shooting for. > > Chris Maxwell | Design Engineer - Optical Division > email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 > > NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA > web www.nettest.com | tel +1 315 797 4449 | > > > -Original Message- > > From: Gibling, Vic [SMTP:vic.gibl...@marconi.com] > > Sent: Wednesday, June 12, 2002 3:26 AM > > To: emc-p...@majordomo.ieee.org > > Subject: An ESD question > > > > > > > > Dear Group > > > > I tried to find David Pommerenke article's in the Journal of ESD on the Web > > but alas no downloadable version was found, so may I ask the group a > > question? > > > > We have an ESD field failure which is occurring in dry hot countries ( no > > surprise )which can be recreated with an ESD of -800V. In an attempt to get > > a high incidence of discharges we used a dehumidifier to create a dry > > environment. The result was a reduction in discharges. > > > > Thinking the problem through -now- as a dry atmosphere will encourage the > > production of high level ESD and a humid environment inhibits the charge to > > a lesser level, presumably because it 'leaks' away. Then is it wrong for us > > to attempt to 'dry' the local atmosphere in the hope of gaining consistent > > ESD from an ESD gun, that is to say the more humid the environment the more > > efficiently the discharge will transfer to the victim? > > > > Incidentally, to add to the thread regarding intermediate level testing for > > ESD and EFT. This exercise has revealed different failure mechanisms at > > different ESD levels. > > > > Your views would be appreciated. > > > > Vic Gibling > > Compliance Engineer > > Marconi Applied Technologies > > > > > > > > --- > > 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: > >
Re: An ESD question
As has been pointed out by Mr. Woods, humidity is only one of many parameters involved with ESD. And simulating a dry environment in a chamber that's completely lined with metal surfaces might not be sufficient for simulating a dry customer environment. ESD failures at differing levels of voltage is an interesting problem since I've had at least two different types of failures each with entirely different casues. 1. A unacceptable hard ESD failure at a level of say 'x KV' and any level higher is most likely a grounding problem. To lower level 'x KV', look at the grounding setup. 2. A unacceptable hard ESD failure at a level of say 'x KV' but possibly no failure above this until a higher level is reached is more a decoupling problem in combination with a grounding problem. For instance, by a "grounding problem" I mean ground wire too short, improperly placed, ground wire too small, maybe braid should be used, maybe a strip of copper should be used, and if a braid or strip of copper are being used then maybe they're not wide enough, etc etc ... By a "decoupling problem" in combination with a grounding problem, I mean the ground problem described above in concert with incorrectly sized decoupling caps, the decoupling caps are improperly placed, leads too long on the caps, wrong sized ferrites if used, improperly placed ferrites, etc etc etc ... Regards, Doug McKean --- 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"
RE: IEC 61000-4-2 ESD & 61000-4-5 Surge lower levels
David, I would add my voice to the notes below. In particular it was for keyboards, and we tested at discrete steps. 2, 4, 6, 8, and then jumped in 4K increments to 12, and 16 - occasionally to 20K for a specific customer requirement. HP for example. We too noted failures at lower levels that did not repeat at higher levels. Principally in the 2 to 8K range, because at the higher levels we changed the acceptance level from not sending out false codes to just not locking up the processor. These were principally in the air discharge mode - but repeatable within the 20 discharges at each test point. By the way I enjoyed the article you sent me on the arc length testing - it at least gives me insight on why the method is presumed to simulate how an actual human/metal ESD event occurs - through air. The data was presented for 5 Kv, but I couldn't tell whether it could also be used for different levels. Sorry, I know from an empirical standpoint you need the data in your hands not just recollection of events, but those tests were done for a different company - but enough voices saying the same thing provide a strong argument for confirming or denying the presumption scientifically. That sounds like its right up your professorial ally and lord knows you have to have some unwitting undergrads you could trick into the process. Certainly would be ideal if it did, or that some adjustment mechanism could be applied to a simulator for each voltage. That would allow for much more automated testing. Gary -Original Message- From: Scott Douglas [mailto:dougl...@naradnetworks.com] Sent: Wednesday, June 12, 2002 5:01 AM To: Pommerenke, David Cc: EMC-PSTC Subject: RE: IEC 61000-4-2 ESD & 61000-4-5 Surge lower levels David, Have been (still am) out of the office testing this week. I am sorry to say that I cannot provide hard data to support my comments. That experience was two lifetimes ago at a different employer. It happened on more than one product model and on more than one of each model. I do know that we would make 50 discharges at each test point. And, there were more than ten test points on each model. Not every test point would exhibit the problem, but those that did were consistent, something like 60% of discharges would cause the system display to scramble. The peak failure voltage was around 1.8 kV, with only a very few failures at 4 kV and none at 8 or 15 kV. All were in contact mode. This was all engineering work prior to official test house testing. We identified the problems and made changes and re-tested. Once we got all tests to pass, we would go for the official test. We had several of these type of problems. Once was the scrambled (actually went black) LCD display. Solved by shielding the cable to the display and termination resistors on the display PCB. Another time was black lines in the recorded output (film recorder products). This was corrected by proper grounding of the I/O connector shell. Third time was system hang-up. If I recall this one correctly, we added decoupling caps to chassis ground at the I/O connector on the mother board. In all cases, the problems were at mid level tests, usually 2 or 4 kV, rarely at 8 kV, and never at 15 kV. Scott At 08:33 PM 6/10/02 -0500, you wrote: >Dear Scott, > >(1) >I have looked at quite a bit of literature that plots > >Failure propatibility vs. Stress level in contact mode like testing > >and have seen very few none-monotonic EUTs that show the none-monotonic >behavior over a larger voltage range. > >(2) >In my five year test practise at HP, I have only seen one EUT that failed >at lower levels and passed at higher levels in contact mode. > > >If you have data that shows"As others have said, I have seen numerous >failures at less than the maximum required test voltage while the same >system passes at the max required voltage." please share that data with me >if it is in contact mode and if the number of discharges at each level is >large enough to obtain an acceptable confidence level. > >Regards > >David Pommerenke > --- 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" ---
Shock and Vibration
Hi All, Does anyone know what "IEC 48D (Secretariat) 76" would be? It is called out in the IEEE 1386:2001 standard for CMC cards as shock and vibration requirements. I assumed that IEC 48D was a standard but apparently that is not the case. SC 48D is a Subcommittee dealing with Mechanical Structures for Electronic Equipment; so I'm thinking that IEC 48D (Secretariat) 76 is the proceedings from one of their meetings but I have had no luck in locating any information about it. My Marketing gurus are asking me if we meet these requirements but I don't know what the requirements are; so its kind of hard to give them an answer. :-) Thanks for your help. Bill ***Artesyn Communication Products, LLC** Bill Fleury Email: bi...@artesyncp.com Compliance Engineer Phone: 608-826-8375 8310 Excelsior DriveFax: 608-831-8844 Madison, WI 53717 "Friends are those people who know the words to the song in your heart and sing them back to you when you have forgotten the words." (unattributed) *** Visit us at www.artesyn.com/cp ** <> <>
CISPR 17
All I have a number of questions concerning specification of mains filters: The first is can somebody explain what CISPR 17 is and how it is used to produce response curves for filters? Secondly, manufacturers data for filter response curves refer to 50ohm - 50ohm measurements and unbalanced 100ohm - 0.1ohm curves. Can anyone tell me how these different impedances are introduced to the system? are they in series or parallel with the filter input? Finally, has anybody been able to simulate a common mode emc filter and reproduce the curves given in manufacturers data? Thanks Ian Gordon _ This message has been checked for all known viruses by UUNET delivered through the MessageLabs Virus Control Centre. For further information visit http://www.uk.uu.net/products/security/virus/ --- 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"
Laser Declaration for Canada
Dear All, A company wishes to hand carry a Class IIIb laser device from overseas into Canada. The laser device will be installed in a machine manufactured by same company for measurement purposes (machine is Class I after laser installation). After measurements, the laser device will be hand carried back to its origin country. Is there an exemption similar to the FDA Form 2877 used in the US? If so what is the Canadian Form to be submitted to Canadian Customs amd where can I get a copy? This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 http://www.itl.co.il http://www.i-spec.com --- 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"
RE: An ESD question
Vic, I agree, your product is probably seeing field failures because of the dry conditions. These dry conditions make the probability of an ESD event higher. This is due to the fact that, as personnel walk across carpets or rub their clothing on chairs, there is no humidity in the air to help bleed and equalize charge. So, they have a higher probability of charging up and a higher probability of discharging to your equipment. (You probably already know this.) Of course, your problems may not be due to people discharging to your equipment. It could be due to some other source of ESD. It could be a discharge from a nearby object. However, the same argument holds. The dry atmosphere increases the probability. (Hence the static cling present in clothes that come out of a dryer.) So, in both cases, you are probably seeing more failures in a dry atmosphere because the probability of an ESD event is higher. Higher failure rates in dry atmospheres are due to this probability increase. The higher failure rate is probably not due to a dry atmosphere ESD event being different from a humid atmosphere ESD event. For testing, you are already generating the ESD event with a simulator. The ESD generator takes probability out of the equation. You can generate a discharge whenever you want. So, in my humble opinion you don't need to simulate the dry conditions. I would simply follow IEC 1000-4-2, which recommends test conditions with a humidity level between 30% and 60%. With this combination of ESD generator and humidity, you should get a discharge whenever you want; and it should couple to the victim in proper fashion. I agree that you will see different performance at different levels. I have seen failures at 4KV air discharge that are not repeatable with 8KV air discharge. So it is worth the time to test at lower levels until you get up to the compliance level that you are shooting for. Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | > -Original Message- > From: Gibling, Vic [SMTP:vic.gibl...@marconi.com] > Sent: Wednesday, June 12, 2002 3:26 AM > To: emc-p...@majordomo.ieee.org > Subject: An ESD question > > > > Dear Group > > I tried to find David Pommerenke article's in the Journal of ESD on the Web > but alas no downloadable version was found, so may I ask the group a > question? > > We have an ESD field failure which is occurring in dry hot countries ( no > surprise )which can be recreated with an ESD of -800V. In an attempt to get > a high incidence of discharges we used a dehumidifier to create a dry > environment. The result was a reduction in discharges. > > Thinking the problem through -now- as a dry atmosphere will encourage the > production of high level ESD and a humid environment inhibits the charge to > a lesser level, presumably because it 'leaks' away. Then is it wrong for us > to attempt to 'dry' the local atmosphere in the hope of gaining consistent > ESD from an ESD gun, that is to say the more humid the environment the more > efficiently the discharge will transfer to the victim? > > Incidentally, to add to the thread regarding intermediate level testing for > ESD and EFT. This exercise has revealed different failure mechanisms at > different ESD levels. > > Your views would be appreciated. > > Vic Gibling > Compliance Engineer > Marconi Applied Technologies > > > > --- > 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" --- 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.
RE: An ESD question
Humidity is not the only variable, and may not be your major variable. Repeatability of ESD results is a statistical problem. Consider the variables: -humidity -approach speed (for non-contact discharge) -angle of the probe (for non-contact discharge) -synchronization of the ESD application with the various logic states of the EUT -rise time and peak di/dt variance as applied ESD voltage is changed -variance between ESD guns And I am sure there are more variables. The only way one can really determine a product's real ESD immunity is to apply thousands of hits at different voltage levels and apply a statistical evaluation. In the end, one can only say that the equipment is immune to X volts with Y confidence. Good luck, Richard Woods Sensormatic Electronics Tyco International -Original Message- From: Gibling, Vic [mailto:vic.gibl...@marconi.com] Sent: Wednesday, June 12, 2002 3:26 AM To: emc-p...@majordomo.ieee.org Subject: An ESD question Dear Group I tried to find David Pommerenke article's in the Journal of ESD on the Web but alas no downloadable version was found, so may I ask the group a question? We have an ESD field failure which is occurring in dry hot countries ( no surprise )which can be recreated with an ESD of -800V. In an attempt to get a high incidence of discharges we used a dehumidifier to create a dry environment. The result was a reduction in discharges. Thinking the problem through -now- as a dry atmosphere will encourage the production of high level ESD and a humid environment inhibits the charge to a lesser level, presumably because it 'leaks' away. Then is it wrong for us to attempt to 'dry' the local atmosphere in the hope of gaining consistent ESD from an ESD gun, that is to say the more humid the environment the more efficiently the discharge will transfer to the victim? Incidentally, to add to the thread regarding intermediate level testing for ESD and EFT. This exercise has revealed different failure mechanisms at different ESD levels. Your views would be appreciated. Vic Gibling Compliance Engineer Marconi Applied Technologies --- 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" --- 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"
RE: IEC 61000-4-2 ESD & 61000-4-5 Surge lower levels
David, Have been (still am) out of the office testing this week. I am sorry to say that I cannot provide hard data to support my comments. That experience was two lifetimes ago at a different employer. It happened on more than one product model and on more than one of each model. I do know that we would make 50 discharges at each test point. And, there were more than ten test points on each model. Not every test point would exhibit the problem, but those that did were consistent, something like 60% of discharges would cause the system display to scramble. The peak failure voltage was around 1.8 kV, with only a very few failures at 4 kV and none at 8 or 15 kV. All were in contact mode. This was all engineering work prior to official test house testing. We identified the problems and made changes and re-tested. Once we got all tests to pass, we would go for the official test. We had several of these type of problems. Once was the scrambled (actually went black) LCD display. Solved by shielding the cable to the display and termination resistors on the display PCB. Another time was black lines in the recorded output (film recorder products). This was corrected by proper grounding of the I/O connector shell. Third time was system hang-up. If I recall this one correctly, we added decoupling caps to chassis ground at the I/O connector on the mother board. In all cases, the problems were at mid level tests, usually 2 or 4 kV, rarely at 8 kV, and never at 15 kV. Scott At 08:33 PM 6/10/02 -0500, you wrote: Dear Scott, (1) I have looked at quite a bit of literature that plots Failure propatibility vs. Stress level in contact mode like testing and have seen very few none-monotonic EUTs that show the none-monotonic behavior over a larger voltage range. (2) In my five year test practise at HP, I have only seen one EUT that failed at lower levels and passed at higher levels in contact mode. If you have data that shows"As others have said, I have seen numerous failures at less than the maximum required test voltage while the same system passes at the max required voltage." please share that data with me if it is in contact mode and if the number of discharges at each level is large enough to obtain an acceptable confidence level. Regards David Pommerenke --- 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"
Re: IEC 61000-4-5 Surge Lower Levels
With reference to EN 61000-4-4, the fast transient burst standard. As with ESD, we also test from low levels upwards. As far as I can remember, we have not had a point where a failure only occurred in the middle of the test range. I must also admit that the reasons for testing from low levels upwards is not so much to thoroughly test to meet standards, but to protect our products. In the early days of these tests, when products were not as well protected as they are now, we soon found that once a failure occured at a low level, increasing the levels to see what happened simply increased the levels of damage. Our expertise in design has since improved, and apart from areas that we suspect may be susceptible we continue increasing levels to see the effect - hence discovering the oddity with an ESD test. From comments on this discussion point, it seems well worth continuing with this practice. Interference with the performance of our product could annoy a customer regardless of the level of the interference source. Regards, Neil Helsby ** This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. This footnote also confirms that this email message has been swept by MIMEsweeper for the presence of computer viruses. www.mimesweeper.com ** --- 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"
SV: mains leads with integral ferrites
Hello Chris, Try Kabelverk Eupen AG http://www.eupen.com/ They have a number of types, the site is down for the moment but try later. Best regards Helge Knudsen Test & Approval manager Niros Telecommunication Hirsemarken 5 DK-3520 Farum Denmark Tel +45 44 34 22 51 Fax +45 44 99 28 08 email h.knud...@niros.com -Oprindelig meddelelse- Fra: Colgan, Chris [mailto:chris.col...@tagmclaren.com] Sendt: 11. juni 2002 11:16 Til: 'Emc-Pstc' (E-mail) Emne: mains leads with integral ferrites Hello Can anyone send me details of manufacturers or suppliers of the above? Cheers Chris Colgan Compliance Engineer TAG McLaren Audio Ltd The Summit, Latham Road Huntingdon, Cambs, PE29 6ZU *Tel: +44 (0)1480 415 627 *Fax: +44 (0)1480 52159 * Mailto:chris.col...@tagmclaren.com * http://www.tagmclaren.com ** Please visit us at www.tagmclaren.com ** The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. Important Note: Any typographical, clerical or other error in this communication is subject to correction without any liability on the part of TAG McLaren Audio Limited. Any orders placed shall be subject to acceptance by TAG McLaren Audio Limited on its standard terms and conditions of sale which shall govern the contract for the sale and purchase of the products ordered to the exclusion of any other terms and conditions. TAG McLaren Audio Ltd The Summit, 11 Latham Road Huntingdon, Cambs, PE29 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) ** Please visit us at www.tagmclaren.com ** --- 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" --- 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"
RE: mains leads with integral ferrites
Mains leads, and other cables, with a built-in ferrite loaded layer are used in military equipment and demanding instrumentation applications. Try http:www.eupen.com/cable/emc/emc01.html Regards, Peter -Original Message- From: Colgan, Chris [mailto:chris.col...@tagmclaren.com] Sent: Tuesday, June 11, 2002 10:16 AM To: 'Emc-Pstc' (E-mail) Subject: mains leads with integral ferrites Hello Can anyone send me details of manufacturers or suppliers of the above? Cheers Chris Colgan Compliance Engineer TAG McLaren Audio Ltd The Summit, Latham Road Huntingdon, Cambs, PE29 6ZU *Tel: +44 (0)1480 415 627 *Fax: +44 (0)1480 52159 * Mailto:chris.col...@tagmclaren.com * http://www.tagmclaren.com ** Please visit us at www.tagmclaren.com ** The contents of this E-mail are confidential and for the exclusive use of the intended recipient. If you receive this E-mail in error, please delete it from your system immediately and notify us either by E-mail, telephone or fax. You should not copy, forward or otherwise disclose the content of the E-mail. Important Note: Any typographical, clerical or other error in this communication is subject to correction without any liability on the part of TAG McLaren Audio Limited. Any orders placed shall be subject to acceptance by TAG McLaren Audio Limited on its standard terms and conditions of sale which shall govern the contract for the sale and purchase of the products ordered to the exclusion of any other terms and conditions. TAG McLaren Audio Ltd The Summit, 11 Latham Road Huntingdon, Cambs, PE29 6ZU Telephone : 01480 415600 (+44 1480 415600) Facsimile : 01480 52159 (+44 1480 52159) ** Please visit us at www.tagmclaren.com ** --- 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"
An ESD question
Dear Group I tried to find David Pommerenke article's in the Journal of ESD on the Web but alas no downloadable version was found, so may I ask the group a question? We have an ESD field failure which is occurring in dry hot countries ( no surprise )which can be recreated with an ESD of -800V. In an attempt to get a high incidence of discharges we used a dehumidifier to create a dry environment. The result was a reduction in discharges. Thinking the problem through -now- as a dry atmosphere will encourage the production of high level ESD and a humid environment inhibits the charge to a lesser level, presumably because it 'leaks' away. Then is it wrong for us to attempt to 'dry' the local atmosphere in the hope of gaining consistent ESD from an ESD gun, that is to say the more humid the environment the more efficiently the discharge will transfer to the victim? Incidentally, to add to the thread regarding intermediate level testing for ESD and EFT. This exercise has revealed different failure mechanisms at different ESD levels. Your views would be appreciated. Vic Gibling Compliance Engineer Marconi Applied Technologies --- 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"
RE: DOC "Assembled from tested components"
No but there have been several companies in the UK that were closed down by Enforcement Offices until they corrected Safety and EMC defects that they were discovered. Another company voluntarily ceased production for 6v months whilst tooling was modified. Best regards Gregg Gregg Kervill DipIM, MIMgt, MIEEE VP Engineering Test4Safety.com Inc PO Box 310, Reedville, VA 22539. USA Phone ( 804) 453-3141 Fax(804) 453-9039 --Original Message- -From: owner-emc-p...@majordomo.ieee.org -[mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of John Juhasz -Sent: Tuesday, June 11, 2002 8:31 AM -To: 'Gonzalez, Kenneth P (Rocky)' -Cc: emc-p...@majordomo.ieee.org -Subject: RE: DOC "Assembled from tested components" - - - -Rocky, - -While your message indicates that the FCC may not have a problem -with the 'assembled from tested components' concept, it does not -mean that the end-product will actually meet the limits. -Poor routing of internal cables, insufficient grounding, just to -mention a couple of items, can cause failures. This is why -the EC doesn't have faith CE + CE = CE. -Although it may work in some cases, it doesn't compare to -actual testing. If you're going to 'mass produce' a particular -configuration, take some time and check the emissions. -You might surprised what you find. In the long run it doesn't -pay to be 'dollar wise and pound foolish'. - -Just my opinion. - -GE Interlogix - -John A. Juhasz -Fiber Options Div. -Bohemia, NY - - - -> All, -> Has anyone successfully issued a DOC using the -"assembled from -tested components" method for a personal computer? I have not -been able to -find a floppy disk drive manufacturer that has any DOC -documentation for -their device; even the ones marketing directly to home users. -Have I just -not found the right manufacturer? -> -> Best regards, -> -> Rocky -> -)-(- -> -> Kenneth P. Gonzalez (Rocky) -> Intergraph Solutions Group -> Integrated Products Division -> 170 Graphics Drive -> Madison, Alabama, USA 35758 -> phone (256) 730-2131 -> fax (256)730-2424 -> kpgon...@ingr.com - -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" - --- 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"
