Re: ESD testing
The fun part of air discharges to insulating surfaces is that things are not always what they appear to be. The air discharge can find a way around lots of apparent insulation to find the nearest conductor and insert all sorts of havoc in the system. - Bill Indecision may or may not be the problem. --- On Mon, 5/18/09, Gordon,Ian ian.gor...@edwardsvacuum.com wrote: From: Gordon,Ian ian.gor...@edwardsvacuum.com Subject: ESD testing To: IEEE EMC SAFETY PSTC emc-p...@ieee.org Date: Monday, May 18, 2009, 7:09 AM All Is it necessary to apply both air contact discharges to equipment given the following?: Looking at 61000-4-2 I believe the critical part is the first paragraph of section 7 .Test set-up. .application of discharges to the EUT in the following manner: a) contact discharge to the conductive surfaces and coupling planes; b) air discharge at insulating surfaces. it does not say for air discharge at insulating AND conductive surfaces. The table in section. 8.3.1 is just for conductors but is essentially a restatement of the above. I cannot see any other part of the spec that implies the opposite. Ian Gordon --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- --- The contents of this email and any attachments are confidential and are provided solely for the use of the intended recipient(s). If you are not the intended recipient, you are hereby notified that any copying, disclosure, distribution, or use of this e-mail, its attachments or any information contained therein is unauthorized and strictly prohibited and you should please contact the sender immediately and delete this e-mail and any attachments from your system. No responsibility is accepted for any virus or defect that might arise from opening this e-mail or attachments, whether or not it has been checked by anti-virus software. - 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 http://us.mc01g.mai .yahoo.com/mc/compose?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...@socal.rr.com h tp://us.mc01g.mail.yahoo.com/mc/compose?to=emcp...@socal.rr.com Mike Cantwell mcantw...@ieee.org htt ://us.mc01g.mail.yahoo.com/mc/compose?to=mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org http: /us.mc01g.mail.yahoo.com/mc/compose?to=j.bac...@ieee.org David Heald: dhe...@gmail.com http:/ us.mc01g.mail.yahoo.com/mc/compose?to=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
RE: ESD testing
Ian, Have you checked the relevant product standard for your application? 61000 series is really only a description of test setup and methodology. The product standard would have the actual specifications. For example, EN55024 for ITE Contact discharge is usually the preferred method of discharge when available. My interpretation has always been that it's an either/or kind of scenario. Adam Rudd From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Gordon,Ian Sent: Monday, May 18, 2009 7:09 AM To: IEEE EMC SAFETY PSTC Subject: ESD testing All Is it necessary to apply both air contact discharges to equipment given the following?: Looking at 61000-4-2 I believe the critical part is the first paragraph of section 7 .Test set-up. .application of discharges to the EUT in the following manner: a) contact discharge to the conductive surfaces and coupling planes; b) air discharge at insulating surfaces. it does not say for air discharge at insulating AND conductive surfaces. The table in section. 8.3.1 is just for conductors but is essentially a restatement of the above. I cannot see any other part of the spec that implies the opposite. Ian Gordon --- --- --- --- --- --- --- --- --- --- --- --- --- The contents of this email and any attachments are confidential and are provided solely for the use of the intended recipient(s). If you are not the intended recipient, you are hereby notified that any copying, disclosure, distribution, or use of this e-mail, its attachments or any information contained therein is unauthorized and strictly prohibited and you should please contact the sender immediately and delete this e-mail and any attachments from your system. No responsibility is accepted for any virus or defect that might arise from opening this e-mail or attachments, whether or not it has been checked by anti-virus software. - 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...@socal.rr.com 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...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: ESD testing
In message 2AA8A4298DECF8469C66C8F3A2B9589201211031@GB02QEX01PEDV27.rmhost1.local, dated Mon, 18 May 2009, Gordon,Ian ian.gor...@edwardsvacuum.com writes: Is it necessary to apply both air contact discharges to equipment given the following?: Looking at 61000-4-2 I believe the critical part is the first paragraph of section 7 .Test set-up. .application of discharges to the EUT in the following manner: a) contact discharge to the conductive surfaces and coupling planes; b) air discharge at insulating surfaces. it does not say for air discharge at insulating AND conductive surfaces. The table in section. 8.3.1 is just for conductors but is essentially a restatement of the above. I cannot see any other part of the spec that implies the opposite. 61000-4-2- is a Basic standard and doesn't (or shouldn't) specify exactly what is required for specific products. Those details are specified in the relevant Product or Product Family standard or, if they don't exist, in the applicable Generic standard. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - 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...@socal.rr.com Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
RE: ESD testing - automotive
Vic, I wonder how realistic this type of test is. It does model a charged person touching the floating device. But another ESD mode is when a person is holding the device and touches the device to the car body. In this case it is more like a CDM discharge with very high current for the time it takes the energy to propagate to the end of the device and back - or not. The person holding the phone does act as a fairly good termination as the device characteristic impedance will be close to the characteristic impedance of the persons arm - about 300 ohms. In this situation the high current will exist for the time it takes the signal to propagate one way. For a cell phone the high current will exist for a few hundred picoseconds. Dave Cuthbert LINEAR TECHNOLOGY CORPORATION Internet Email Confidentiality Footer This e-mail transmission, and any documents, files or previous e-mail messages attached to it may contain confidential information that is legally privileged. IF you are not the intended recipient, or a person responsible for delivering it to the intended recipient, you are hereby notified that any disclosure, copying, distribution or use of any of the information contain in or attached to this transmission is STRICTLY PROHIBITED. If you have received this transmission in error, please immediately notify me by reply e-mail, or by telephone at (719)593-1579, and destroy the original transmission and its attachments without reading or saving in any manner. Thank You From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Vic Gibling-NonTRW Sent: Friday, August 18, 2006 5:43 AM To: emc-p...@ieee.org Subject: ESD testing - automotive Dear colleagues, The unpowered product is required to be insulated from the ground plane. The product is NOT grounded. It is subjected to a number of discharges at a rate of 1 - 10 seconds. If the charge does not neutralise before the next discharge what happens and why is this test done in this manner? The same product (and arrangement) receives discharges to each connector pin. To ease applying the discharge to small pins a short single pin extender is used. The procedure is to remove the extender after fulfilling the discharge requirements and use it for the next. It is removed by hand. Any comments? I would appreciate your views and comments. Vic Vagabond EMC Engineer - 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 emc-p...@ieee.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:emc-p...@daveheald.com 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 emc-p...@ieee.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:emc-p...@daveheald.com 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 __
RE: ESD testing - automotive
Vic, An unpowered product does not have the ground wire (green wire) in the power cord as an AC powered system (such as a PC) does. So, the ESD current injected into the unpowered prodcut does not have a direct conductive path to the ground plane and back to the ESD generator. This is the reason why the unpowered prodcut should not be grounded during ESD testing. As there is no ground connection during the test, we need to remove the charges off the system before the next zap. Otherwise due to the residual charges on the system, the ESD generator can not fully discharge on the next zap. There are different methods to remove the charges: use a conductive brush and brush off the charges between zaps, make a momentary ground connection thru a 1 MOhm resistor between zaps, etc. If you are concerned about the possibility of discharges from the human body into the pins, the person touching the pin extender could wear a ground strap. This way, the pins will not receive any unwanted human ESD. Thanks, Ram Chundru System Level ESD Engineer Texas Instruments. _ From: emc-p...@ieee.org on behalf of Vic Gibling-NonTRW Sent: Fri 8/18/2006 6:43 AM To: emc-p...@ieee.org Subject: ESD testing - automotive Dear colleagues, The unpowered product is required to be insulated from the ground plane. The product is NOT grounded. It is subjected to a number of discharges at a rate of 1 - 10 seconds. If the charge does not neutralise before the next discharge what happens and why is this test done in this manner? The same product (and arrangement) receives discharges to each connector pin. To ease applying the discharge to small pins a short single pin extender is used. The procedure is to remove the extender after fulfilling the discharge requirements and use it for the next. It is removed by hand. Any comments? I would appreciate your views and comments. Vic Vagabond EMC Engineer - 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 emc-p...@ieee.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:emc-p...@daveheald.com 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 __ - 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 emc-p...@ieee.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: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: ESD Testing Method
Alex, Amendment 2:2001 to EN 61000-4-2:1995 (same as Amendment A2:2000 to IEC 61000-4-2:1995) calls for discharging ungrounded equipment, or ungrounded part(s) of equipment between ESD zaps. You use a bleeder cable with 470k resistors at both ends, connected to the horizontal coupling plane for tabletop equipment. You may leave the bleeder cable attached if it doesn't bother the equipment under test (EUT). But the definitive method is to briefly touch the bleeder cable to the EUT, zap the EUT, briefly touch the bleeder cable to the EUT, etc. This amendment also permits: * Long delays between ESD zaps. * Using a carbon-fiber brush with bleeder resistors. * Using an air ionizer (must be turned off for the air-discharge zaps). John Barnes KS4GL, SM IEEE dBi Corporation http://www.dbicorporation.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: ESD Testing Method
Amendment 2 to IEC 61000-4-2:1995 specifically addresses the test method for ungrounded equipment. Refer to section 7.1.3 of that standard. To answer your first question, yes the charge applied to the product should be discharged before applying the next discharge. Regarding your follow up question, if you apply +8kV discharge followed by -8kV discharge, without removing the charge from the EUT between the discharges, then the actual potential voltage is 16kV which could very well overstress the product. Jim Hulbert Pitney Bowes Alex McNeil alex.mcneil@ingenicoforTo: 'emc-p...@majordomo.ieee.org' emc-p...@majordomo.ieee.org tronic.com cc: Sent by:Subject: ESD Testing Method owner-emc-pstc@majordomo .ieee.org 12/03/2002 11:15 AM Please respond to Alex McNeil Hi Guys, 1. For double insulated products (non-earthed) is it correct to state that the ESD test point, for Contact Discharge (CD) tests, should be discharged prior to applying the next discharge (I am sure I read this somewhere, but)? 2. As a follow on from the first question, I have a product that will pass +8KV Contact Discharge (CD) in +2KV steps. It will also pass -8KV CD in -2KV steps. However, if I test +XKV (50 zaps) followed by -XKV (1 zap) it will fail. What is the correct procedure as the standard does not say if +CD should follow -CD or vice versa or step up with the same polarity? In my opinion it would be unlikely in a particular customer environment that the +XKV would be quickly followed by a -XKV (or vice versa). I look forward, as per usual, to your kind and expert responses. Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax:+44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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
RE: ESD Testing Method
Dear Alex McNeil, The intend of the standard is that each discharge is an individual event. This means: Electromagnetic consequence === All charges need to be drained before the next discharge is applied. You may use an Ionizer, a conductive brush, a ground wire etc. to remove the charge from the EUT. Be aware: An Ionizer may change the test results for air discharges a lot. Software consequence It is not the aim to apply an discharge while the EUT is still in some error correcting algorithm. So one can apply discharges at a fast rate, e.g., 20 pulses a sec to up the number of discharges (with 10 discharges the ESD test result uncertainty may be dominated by the time dependence of the susceptability function). Still, one needs to make sure that the EUT is back to its original software status before the next ESD is applied. David Pommerenke -Original Message- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Tuesday, December 03, 2002 10:16 AM To: 'emc-p...@majordomo.ieee.org' Subject: ESD Testing Method Hi Guys, 1. For double insulated products (non-earthed) is it correct to state that the ESD test point, for Contact Discharge (CD) tests, should be discharged prior to applying the next discharge (I am sure I read this somewhere, but)? 2. As a follow on from the first question, I have a product that will pass +8KV Contact Discharge (CD) in +2KV steps. It will also pass -8KV CD in -2KV steps. However, if I test +XKV (50 zaps) followed by -XKV (1 zap) it will fail. What is the correct procedure as the standard does not say if +CD should follow -CD or vice versa or step up with the same polarity? In my opinion it would be unlikely in a particular customer environment that the +XKV would be quickly followed by a -XKV (or vice versa). I look forward, as per usual, to your kind and expert responses. Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax:+44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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: ESD Testing Method
Alex, The new A2 (Feb 2001) of EN61000-4-2:1995 is very clear on this point. Paragraph 7.1.3 states the charge on the EUT shall be removed prior to each applied ESD pulse. I think this would take care of the problem you are seeing with the charge reversal that you talk about in question 2. Dan Kinney Horner APG --- 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: ESD Testing Method
Most labs I have ever worked with return the EUT to a neutral level prior to applying opposite polarity discharges, which means use a wire attached to reference ground to short out any accumulated charge. However this has usually been with air discharge to non-conductive surfaces such as an overlay. The reasoning is that an opposite polarity discharge is twice the required level and does not relate to a real world event. Darrell Locke Advanced Input Devices -Original Message- From: Alex McNeil [mailto:alex.mcn...@ingenicofortronic.com] Sent: Tuesday, December 03, 2002 8:16 AM To: 'emc-p...@majordomo.ieee.org' Subject: ESD Testing Method Hi Guys, 1. For double insulated products (non-earthed) is it correct to state that the ESD test point, for Contact Discharge (CD) tests, should be discharged prior to applying the next discharge (I am sure I read this somewhere, but)? 2. As a follow on from the first question, I have a product that will pass +8KV Contact Discharge (CD) in +2KV steps. It will also pass -8KV CD in -2KV steps. However, if I test +XKV (50 zaps) followed by -XKV (1 zap) it will fail. What is the correct procedure as the standard does not say if +CD should follow -CD or vice versa or step up with the same polarity? In my opinion it would be unlikely in a particular customer environment that the +XKV would be quickly followed by a -XKV (or vice versa). I look forward, as per usual, to your kind and expert responses. Kind Regards Alex McNeil Principal Engineer Tel: +44 (0)131 479 8375 Fax:+44 (0)131 479 8321 email: alex.mcn...@ingenicofortronic.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: ESD Testing
We are getting off the track of my original question. Given that the test procedures are identical (number of hits, location, air discharge, etc.) will one gun (IEC 801-2 or EN 61000-4-2) yield worse results than the other? The best information I have at this point is that the speed of approach is the major contributor to differences between results, even with the same gun. -- From: Michael Hopkins [SMTP:mhopk...@thermokeytek.com] Sent: Wednesday, September 12, 2001 7:13 AM To: Patrick Lawler; EMC-PSTC Subject: Re: ESD Testing May be some confusion here:: There is NO published version of 61000-4-2 that specifies 50 discharges. It may be in CISPR, but not in the IEC basic standard.. There are some amendments to IEC 61000-4-2, but these deal with use of the HCP, identification of operator accessable points, and testing of double insulated products. Now, there IS an early draft version of a revision of IEC 61000-4-2, which at this stage is a working draft within SC77B WG9. (There was a CD issued, but there have been many, many significant changes to this document, and is far from a version that could be circulated to industry.) This draft does talk about 50 discharges per point; however, I emphisize: THIS IS A WORKING DRAFT --- it is NOT likely to be published as it now stands. Additionally, WG9 met Monday and yesterday (September 10/11) and made many changes to the document and I don't anticipate another CD for several months. Hope this helps. It's always a problem when early drafts of documents begin to circulate. Michael Hopkins Thermo KeyTek Member, SC77B WG9 Convenor, SC77B WG11 - Original Message - From: Patrick Lawler plaw...@west.net To: EMC-PSTC emc-p...@ieee.org Sent: Tuesday, September 11, 2001 8:15 PM Subject: Re: ESD Testing I don't have the IEC 61000-4-2 ammendment, but CISPR24:1997 (Immunity for ITE) does have the phrases ... a minimum of 50 discharges at each point, and ... test points shall receive at least 50 direct contact discharges. Maybe this is what you were thinking about. --- Patrick Lawler plaw...@west.net On Mon, 10 Sep 2001 13:25:49 -0700, Doug McKean dmck...@corp.auspex.com wrote: Both are 8kV air discharge, both require performance criteria B, but I'd say the current version of 61000-4-2 is more severe. Doesn't the current IEC 61000-4-2:1995 + A1:1998 version require a minimum of 50 hits per test point whereas the 1984 version didn't? I don't remember the specifics of the 84 version and I don't have any reference to it. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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: No longer online until our new server is brought online and the old messages are imported into the new server. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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: No longer online until our new server is brought online and the old messages are imported into the new server. --- This message is from the IEEE EMC Society
Re: ESD Testing
I don't have the IEC 61000-4-2 ammendment, but CISPR24:1997 (Immunity for ITE) does have the phrases ... a minimum of 50 discharges at each point, and ... test points shall receive at least 50 direct contact discharges. Maybe this is what you were thinking about. --- Patrick Lawler plaw...@west.net On Mon, 10 Sep 2001 13:25:49 -0700, Doug McKean dmck...@corp.auspex.com wrote: Both are 8kV air discharge, both require performance criteria B, but I'd say the current version of 61000-4-2 is more severe. Doesn't the current IEC 61000-4-2:1995 + A1:1998 version require a minimum of 50 hits per test point whereas the 1984 version didn't? I don't remember the specifics of the 84 version and I don't have any reference to it. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: ESD Testing
Both are 8kV air discharge, both require performance criteria B, but I'd say the current version of 61000-4-2 is more severe. Doesn't the current IEC 61000-4-2:1995 + A1:1998 version require a minimum of 50 hits per test point whereas the 1984 version didn't? I don't remember the specifics of the 84 version and I don't have any reference to it. - 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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: No longer online until our new server is brought online and the old messages are imported into the new server.
RE: ESD Testing
Dear Richard, Hewlett Packard tests to more than 15 kV. But please be aware: The severeness of an ESD tests does not always increase with the test voltage. Depending on the physical failure mechanism (energy, current, derivative, fields, E-field, H-field, etc.) it will go down with voltage for air discharge. Testing 15 kV is done for the following reasons: - An environment with a LAREG likelyhood of 15 kV: All mobile environments. Spacecrafts (special case) - Low likelyhood of 15 kV ESDs but an EUT which needs to be very reliable: Medical Safety related - The company wants to ensure that the EUT will pass 8 kV after some years of usage. Changes are: Contamination Cracks in plastic joints etc. Moisture The effect of these parameters on the sparking length are not easy to predict. - The company wants to ensure that it will pass 10 kV at high altidue. Note that the breakdown distance is somewhat 1/proportional to air pressure. If you pass 15 kV in San Diego, you probably pass no more than 10 kV in Denver. - Customer requirement. - To impress the customer. - As a company tradition. In most cases 15 kV testing is done in air discharge. If you are looking not only for survival, but for error-free operation, you should use contact mode testing whereever possible. If you look for error-free operation, it is also very important to test at a lower voltage in contact mode (e.g., 6kV) using a fast risetime simualtor (e.g., 100 ps). There are a larger set of simulators which can do 15 kV. E.g., KeyTek 2000 NoiseKen some Schaffner (not sure) some EM-Test (not sure) Failure criteria depends on the product. David Pommerenke University Missouri-Rolla, 1870 Minor Circle, 118 EECH Rolla, MO 65409-0040 ph: 573 341 4531 home: 573 341 5835 fax: 573 341 4532 email: pommere...@ece.umr.edu -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Tuesday, August 14, 2001 8:56 AM To: emc-p...@majordomo.ieee.org Subject: ESD Testing Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall, --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD Testing
Richard o What types of products card operated locking systems o What type of user environment for hotels o What is the rational for testing above 15 kV The manufacturer test up to 20kV, wool carpet makes large ESD problems .. o What is the pass/fail criteria above 15 kV Criteria A, no failure . Best regards Amund Westin, Oslo/Norway -- Get your firstname@lastname email for FREE at http://Nameplanet.com/?su --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: ESD Testing
Richard wrote ... Do any of you perform ESD testing at or above 15 kV to improve product robustness? Yes. ISO TR 10605/SAE J1113. 25kV air discharge, 8kV contact What type of user environment Automotive What types of products What is the rational for testing above 15 kV Points accessible from *outside* the vehicle e.g. steering wheels. What test equipment is used above 15 kV Schaffner NSG432, EM TEST ESD-30C What test procedure is used above 15kV I've only tested upto 25kV. Same as for 15kV. Air discharges to body of product, to plane in vicinity of product and to wiring loom. What is the pass/fail criteria above 15 kV We use the same as for 15kV. We aim for ISO Class A (no malfunction) for devices accessible during operation. We opt for Class A @ 15kV, Class B @ 15kV for devices not normally accessible in operation but could become accessible during maintenance. Hope this helps. Best regards - Chris Chileshe - Ultronics Ltd - http://www.ultronics.co.uk -Original Message- From: wo...@sensormatic.com [SMTP:wo...@sensormatic.com] Sent: Tuesday, August 14, 2001 2:56 PM To: emc-p...@majordomo.ieee.org Subject:ESD Testing Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall, _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. _ This message has been checked for all known viruses by Star Internet delivered through the MessageLabs Virus Scanning Service. For further information visit http://www.star.net.uk/stats.asp or alternatively call Star Internet for details on the Virus Scanning Service. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD Testing
Richard, With today's faster circuits low voltage evernts may be more likely a problem than high voltage ones. Low voltage air discharges have much higher di/dt (and therefore interference potential) than high voltage events. A device that passes 15kV may easily fail at 1 kV because the di/di at 1 kV is MUCH higher if it uses logic with sub-nanosecond risetimes. Doug wo...@sensormatic.com wrote: Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall, -- --- ___ _ Doug Smith \ / ) P.O. Box 1457 = Los Gatos, CA 95031-1457 _ / \ / \ _ TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-( ) | o |Email: d...@dsmith.org \ _ /]\ _ / Website: http://www.dsmith.org --- --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: ESD Testing
Gaming machines in Australia are tested to 25kV air discharge and 10kV contact discharge. Gaming regulators are more concerned about intentional interference rather that accidental. I use 61000-4-2 as the basis for my test procedure even though the gaming machine requirements do not specify. Since all software lockups are required to be manually reset by an authorised person, we pretty much test for total immunity i.e., Criteria A. About the only thing that I let through is screen flicker and short duration drop outs in communications. In the US some regulators actually use a high frequency generator, used for testing the integrity of vacuum tubes, in lieu of a proper ESD simulator. These are uncalibrated devices and can be anywhere from 40 to 60kV. Therefore, after I have finished my precompliance testing with this device, it is a matter of crossing my fingers and hope for the best!! Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: 14 August, 2001 23:56 To: emc-p...@majordomo.ieee.org Subject: ESD Testing Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall, -- CONFIDENTIALITY NOTICE -- This email is intended only to be read or used by the addressee. The information contained in this e-mail message may be confidential information. If you are not the intended recipient, any use, interference with, distribution, disclosure or copying of this material is unauthorised and prohibited. Confidentiality attached to this communication is not waived or lost by reason of the mistaken delivery to you. If you have received this message in error, please delete it and notify us by return e-mail or telephone Aristocrat Technologies Australia Pty Limited on +61 2 9413 6300. --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD Testing
This reminds when EMC immunity testing first came out while I worked at another company. No one knew exactly what to expect. So we made our own ESD tester with a TV flyback transformer connected to a variac connected to the AC mains line. The thing could kill you. We could go above 15K easy. The product was very robust anyway. So, we'd keep raising the voltage until it finally cooked. The only time I saw an EMC problem solved by software was to fix a keyboard lockup problem with this tester. A programmer was brought in to write a little subroutine to unlock the keyboard. Worked like a charm. The level of testing was a result of the environment in which the product would finally be used. Very uncontrolled environment. - 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
RE: ESD Testing
Richard, We have gone as high as 20kV. This was done on the control panel with buttons similar to that of your common vcr remote. It was done as a customer requirement. We used the same pass/fail criteria as if it were at 8kV. We use a Schaffner NSG431. Regards, Josh -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Tuesday, August 14, 2001 6:56 AM To: emc-p...@majordomo.ieee.org Subject: ESD Testing Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV Thanks, Richard Woods --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD Testing
The following doesn't directly address the issue of product robustness, but I'll pass it along anyway. My company makes power supplies for use in medical equipment, and some of our customers test to IEC60601-2-24 (safety EMC for medical infusion pumps). This standard requires 15kV air discharges. Because I only have a few pages from IEC60601-2-24:1998, I don't know the pass/fail criteria. On Tue, 14 Aug 2001 09:55:55 -0400, wo...@sensormatic.com wrote: Do any of you perform ESD testing at or above 15 kV to improve product robustness? I have the following questions. o What types of products o What type of user environment o What is the rational for testing above 15 kV o What test equipment is used above 15 kV o What test procedure is used above 15kV o What is the pass/fail criteria above 15 kV --- 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: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net 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://www.rcic.com/ click on Virtual Conference Hall,
Re: ESD Testing in the Production Lines
Alessandro Agostini said: . . .Sometimes in fact the op. amps. connected to the output appeared to be damaged [by production line ESD tests] but only after some days. I strongly recommend thorough ESD testing of designs and design changes. I would never purposely apply ESD to a customer product. ESD is insidious. Some years ago in another life we suspected ESD damage to components during product assembly, and went to great lengths to eliminate the possibility. Later we found a significant decrease in warranty costs; we were having failures SIX MONTHS into product life from manufacturing ESD, and didn+t know it!
Re: ESD Testing in the Production Lines
I' m sure many people have experienced faults in ESD testing, so that they are not a good habit in production lines. I also experienced rare faults in testing some equipment to the EFT/B (IEC 1000-4-4) at test levels of 500V to signal output lines. Sometimes in fact the op. amps. connected to the ouput appeared to be damaged but only after some days. Did any of you experienced anything similar ? - All what above is only my opinion and thus probably wrong! :-) Alessandro Agostini Italponti Firenze (Italy)
Re: ESD Testing in the Production Line
Darrell, Maybe one of their competitors suggested it to them? Opinions are my own, not those of my employer.. Eric Petitpierre Pulsecom Herndon, VA er...@pulse.com __ Reply Separator _ Subject: ESD Testing in the Production Line Author: dlo...@advanced-input.com at SMTP List-Post: emc-pstc@listserv.ieee.org Date:5/14/97 6:43 PM One of our customers routinely does system ESD testing (to the IEC 1000 test level) on their production line. I have always considered ESD testing to be semi-destructive and would rather see type testing followed by strict control of the design. Production line ESD testing seems like it could lead to latent failures. Has anyone else had experience with this? Is this a common practice? Thanks in advance. Darrell Locke Advanced Input Devices
Re: ESD testing on exposed connector(2)
And if you decide to design product to survive zapped connector pins Motorola's dual switching diode MMBD7000LT1, SMT 3-pin clamping device can reduce direct hits to the managable levels. This useful device has maximum surge impedance of only 0.5 Ohms and maximum capacitance of only 1.5 pF. Mirko Matejic email: mmatejic@foxboro The Foxboro Company tel: (508) 549-3185 -- From: ron_well...@hp-paloalto-om4.om.hp.com List-Post: emc-pstc@listserv.ieee.org Date: Mon, 22 Apr 96 09:09:48 -0700 Subject: Re: ESD testing on exposed connector pins To: owner-emc-p...@majordomo.ieee.org, SIM::@msim.co.uk Cc: emc-p...@ieee.org Hello Alan, You assume two things: 1) test houses will zap connectors, and 2) all manufacturers use test houses for EMC Directive compliance In the United States most manufacturers self declare compliance to the EMC Directive unless they take the TCF route and work with a competent body. Do all manufacturers zap connectors? Your guess is as good as mine. Regards, Ron Wellman ++ |Ronald R. Wellman |Corporate Quality Department| |Hewlett-Packard Company|External Product Regulations| |Product Processes Organization |Voice : 415-857-6059| |1501 Page Mill Road, MS 5UL|FAX : 415-857-6340| |Palo Alto, California 94304 USA|E-Mail: well...@corp.hp.com | ++ | Common sense is the collection of prejudices acquired by | | age eighteen. - Albert Einstein | ++ Reply Separator Subject: Re: ESD testing on exposed connector pins Author: Non-HP-owner-emc-pstc (owner-emc-p...@majordomo.ieee.org) at HP-PaloAlto,shargw3 List-Post: emc-pstc@listserv.ieee.org Date:4/19/96 10:05 AM Recently Ron Wellman wrote: I believe that everyone contributing to this thread knows that zapping pins of exposed connector pins is almost always a guaranteed failure. Whether you fix it or not is a business decision, From a European point of view, I would have thought that if the test house did such a test (zapped the pins) and it failed, then you didn't get your Certificate of Conformity (or whatever), which means no CE Mark, which means no can sell, which is not much of a business decision !!! Or am I being simplistic (or even dense !)? Regards, Alan Hudson EMC/EW Specialist Marconi Simulation (Scotland, UK) email1 hud...@msim.co.uk email2 100534@compuserve.com
Re: ESD testing on exposed connector pins
Received: from hpcc01.corp.hp.com by hpcc08.corp.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.4 Openmail) id AA012278233; Fri, 19 Apr 1996 19:43:54 -0700 Received: from hp.com by hpcc01.corp.hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA009328229; Fri, 19 Apr 1996 19:43:50 -0700 Received: from mail.ieee.org (rab.ieee.org) by hp.com with ESMTP (1.37.109.16/15.5+ECS 3.3) id AA150138228; Fri, 19 Apr 1996 19:43:48 -0700 Received: by mail.ieee.org (8.7.3/8.7.3) id MAA22834 for emc-pstc-list; Fri, 19 Apr 1996 12:09:35 -0400 (EDT) Message-Id: 199604191609.maa22...@mail.ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Fri, 19 Apr 96 17:05 GMT From: HUDSON@glamis SIM::@msim.co.uk To: EMC-PSTC emc-p...@ieee.org Subject: Re: ESD testing on exposed connector pins Sender: owner-emc-p...@majordomo.ieee.org Precedence: bulk Reply-To: HUDSON@glamis SIM::@msim.co.uk X-Resent-To: Multiple Recipients emc-p...@majordomo.ieee.org X-Listname: emc-pstc X-List-Description: Product Safety Tech. Committee, EMC Society X-Info: Help requests to emc-pstc-requ...@majordomo.ieee.org X-Info: [Un]Subscribe requests to majord...@majordomo.ieee.org X-Moderator-Address: emc-pstc-appro...@majordomo.ieee.org ... Hello Alan, You assume two things: 1) test houses will zap connectors, and 2) all manufacturers use test houses for EMC Directive compliance In the United States most manufacturers self declare compliance to the EMC Directive unless they take the TCF route and work with a competent body. Do all manufacturers zap connectors? Your guess is as good as mine. Regards, Ron Wellman ++ |Ronald R. Wellman |Corporate Quality Department| |Hewlett-Packard Company|External Product Regulations| |Product Processes Organization |Voice : 415-857-6059| |1501 Page Mill Road, MS 5UL|FAX : 415-857-6340| |Palo Alto, California 94304 USA|E-Mail: well...@corp.hp.com | ++ | Common sense is the collection of prejudices acquired by | | age eighteen. - Albert Einstein | ++ __ Reply Separator _ Subject: Re: ESD testing on exposed connector pins Author: Non-HP-owner-emc-pstc (owner-emc-p...@majordomo.ieee.org) at HP-PaloAlto,shargw3 List-Post: emc-pstc@listserv.ieee.org Date:4/19/96 10:05 AM Recently Ron Wellman wrote: I believe that everyone contributing to this thread knows that zapping pins of exposed connector pins is almost always a guaranteed failure. Whether you fix it or not is a business decision, From a European point of view, I would have thought that if the test house did such a test (zapped the pins) and it failed, then you didn't get your Certificate of Conformity (or whatever), which means no CE Mark, which means no can sell, which is not much of a business decision !!! Or am I being simplistic (or even dense !)? Regards, Alan Hudson EMC/EW Specialist Marconi Simulation (Scotland, UK) email1 hud...@msim.co.uk email2 100534@compuserve.com
Re: ESD testing on exposed connector pins
Ron Wellman suggests that it is a truth universally acknowledged that ESD applied to a connector pin will almost always lead to failure. Without precautions this may be so but for low frequency connections it is possible to protect not only against permanent damage but also against loss of data as required by the EMC tests under the EMC directive. A combination of filtering and clamping very close to the connector can provide the required protection. The closeness to the connector is however vital. The threat from the discharge comes not only from its amplitude but from its very fast rise time (0.7ns). At this speed a path to ground within the equipment of only a couple of inches presents an appreciable impedance and will constitute a radiating antenna broadcasting to the rest of the equipment. Filters built in to the connector with feed through capacitors are best but they should not spread the energy out over such a long period that it is sensed as a valid signal. If you are fighting to keep the bandwith up while providing protection the best scheme is to use a modest filter in the connector to slow the edge of the waveform, closely followed by clamping diodes and then a further filter to reduce the clamp level to below the signal threshold. This can be expensive and bulky if you have a lot of signals but it can be done. Nick Rouse
Re: ESD testing on exposed connector pins
Tony Fredriksson wrote: Often times, ESD related failures can't be traced to the event because they can stress semiconductor junctions without causing an immediate failure. Then a short time later--days, weeks, even months-the stressed component fails prematurely for no apparent reason. So even if a specific case can't be named, it doesn't mean that I/O pin discharges in real life don't cause failures. I can add to this. I have encountered an example whereby testing of an RS 232 connector caused a latent failure in the driver circuit. This failure was interesting in that the circuit still worked properly (albeit with reduced output voltage) but the driver was now oscillating at a couple of hundred MHz causing the apparatus to now fail radiated emissions. James Cunningham Radio Frequency Investigation Ltd Ewhurst Park, Ramsdell Basingstoke Hampshire RG26 5RQ England Tel: (+44) 01256 851193, j...@rfi.co.uk
Re: ESD testing on exposed connector pins
On Wed, 17 Apr 1996 ron_well...@hp-paloalto-om4.om.hp.com wrote: Has anyone ever attributed a real Customer failure of a product to an ESD discharge at an exposed i/o connector? Also, putting a cover over a connector gives us a warm fuzzy feeling that we have protected the product from the Customer and met the requirements of the standard. What is there to prevent a Customer from removing the cover? You might put an warning about static electricity on a label attached to the cover. Then, when the user removes the cover he is reminded that he should discharge himself to the ground frame of the equipment before installing cables to the equipment, thus preventing unadvertent discharge/damage Rgds Rene Isn't this a case where the connector must either be tested directly or protected somehow? For our products, we recommend that such connectors be tested shipped with some sort of protection. I've found that simple plastic dust covers are usually sufficient. This is assuming, of course, that there is a real risk. We have found, as has been noted by someone else, that typical 9, 15 25 female pin D-shell connectors are safe without additional protection as we've never been able to arc directly to a pin during tests (air discharge, of course). But perhaps we're being unnecessarily conservative. I'd like to see more opinions from others who've been through this. Jack Cook, EMC Competency Center Xerox Corporation jcook.el_segu...@xerox.com
Re: ESD testing on exposed connector pins
re: ESD testing directly on the pins of a bare connector. It seems reasonable to exclude testing into a bare connector which will normally be populated with a cable. In that case, testing should be conducted with the cable in place. I think where confusion exists is where there are optional connectors, one or more of which may not be populated in a customer's installation. As an example, many of our laser printers normally have both standard serial (RS-32) parallel I/O connectors. The customer will choose one and leave the other vacant. That unused connector is now vulnerable to ESD. Isn't this a case where the connector must either be tested directly or protected somehow? For our products, we recommend that such connectors be tested shipped with some sort of protection. I've found that simple plastic dust covers are usually sufficient. This is assuming, of course, that there is a real risk. We have found, as has been noted by someone else, that typical 9, 15 25 female pin D-shell connectors are safe without additional protection as we've never been able to arc directly to a pin during tests (air discharge, of course). But perhaps we're being unnecessarily conservative. I'd like to see more opinions from others who've been through this. Jack Cook, EMC Competency Center Xerox Corporation jcook.el_segu...@xerox.com
Re: ESD testing on exposed c
Hi, I have never worked with a lab that has discharged to exposed pins of a connector. I think the basic rationale is that when one approaches a connector with a charged finger, the discharge is most likely to arc to the surface with the most inherent capacitance, which would be the D-shell or grounding ring of the connector, the part connected to the return reference or chassis refernece of the circuit. Discharging to pins under normal circumstances is much less likely. Without knowing more of the detail of this product's construction, it is difficult to determine if the lab is being overly enthusiastic or if it has determined that this particular construction is so far out of the norm that it is highly likely that, under normal use, the pins are the likely discharge point from a charged person or object. Regards, tony_fredriks...@netpower.com -- From: Steve Chin To: emc-pstc Subject: Re: ESD testing on exposed c List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, April 16, 1996 9:44AM Moshe asked about ESD testing directly on the pins of a bare connector. The lab I test with has told me that they do not discharge directly to = the exposed pins of a connector to which no cable is connected. They = quoted many reasons, including the ECMA spec Moshe quoted, as well as the = fact that we usually do the radiated emissions tests with a fully = populated system and the ESD and other immunity tests with a pretty bare = system (which creates the assumption that the end-users will configure = their systems similarly to the radiated emmissions test system, therefore = making the possibility of an end-user discharge to the pins extremely = remote). They said that your argument against discharging directly to the pins = could include the fact that your expected user configuration would = include cables populating those connectors (assuming the vacant = connectors are for peripheral support equipment, not vital connections = for operations). Ah, I ramble on (and I'm probably not intelligible). Steve Chin FWB, Inc. Menlo Park, CA, USA steve_c...@fwb.com
Re: ESD testing on exposed connectors
The rationale offered by Tom Cokenias is fine for equipment that is always configured with cables on all connectors. The pins would then would not come within the criteria that I suggested of the user being reasonably expected to touch them. However many items of equipment are designed with connectors for optional attachments. A PC manufacturer does not expect that every computer sold will used only with a device on every serial and parallel port. The test is intended to simulate a real risk. Where to apply the test should surely be governed by where this risk is real. Nick Rouse
Re: ESD testing on exposed connectors
Moshe, The competent bodies I have dealt with (3) have required ESD testing to metal shells of D connectors and have specifically excluded requirements to test the pins. The rationale has been that the mfr put the connector for a cable to connect to it, meaning the pins will be somewhat protected. The mfr should not be penalized because the user does not choose to configure the system in the way it was designed. Connecting cables to all ports and then testing ports at the cable juntion seems to me to satisfy both the spirit and the letter of the requirement. The(exposed) pins would then not be accessible to the user, and the vulnerability of the EUT can be still tested at locations where cable type may not afford much protection, eg, where flat ribbon or unshielded cables are employed. Tom Cokenias.
Re: ESD testing on exposed connectors
I don't know of any official standard that gives a specific ruling on connector pins. The generic immunity standards refer without comment to the basic standards and the basic standards refer to points accessible to personnel during normal use including customer's maintenance. The overview of immunity tests, standard IEC1000-4-1 reiterates this saying that the ESD shall be applied to all normally accessible points on the EUT The opinion of the Competant body that we use is that if the user can reasonably reach a connector and may do so at some time during any operation that you might reasonably expect him or her to do, the pins of the connector should be tested if there is a fair chance that a finger or metal object approaching the connector would discharge to the contacts rather than the shell. Thus large flat connectors with non-recessed contacts or plastic shelled connectors should have the pins tested but narrow metal shelled connectors with the shell earthed and contacts recessed need only be tested to the shell. A few tests have shown that female BNC's discharge to the shell but male BNC's can discharge to the pin. Standard width D types with female contacts discharge to the shell and those with male contacts nearly always do. Wide shell 3 row D types can discharge to the pins with both sexes. Do not forget the indirect ESD test. I have found that for plastic cased equipment with unscreened wires running away from the connector internally an ESD test to a coupling plane 100mm from a connector face can have more effect than a direct discharge to the pin. Nick Rouse
