All manufactured products have tolerances in their specifications even if the spec sheet doesn't state a tolerance for certain parameters (unless stated as min or max). Even if all the different manufacturers follow the same basic design requirements defined in the test standard, the resultant products will all have tolerances in their output stimulus, even for identical product models by the same manufacturer. And it is possible for these tolerances to cause different product responses.
And how the ESD simulator is used can also affect the test results even if the test configuration complies with the test standard. Example: Years ago we tested a client product that failed in a competitor test lab but passed in our test lab, where the ESD simulator manufacturer and model was identical for both test labs. Investigating further we determined that both labs followed the test requirement setup configuration in all respects (including specified distances), except there was one significant difference. The competitor lab was performing ESD testing in a small fully shielded room with metal walls and no absorbers, whereas our lab performed the test in an open lab environment far from metal structures. I like Bill Owsley's response, test to a higher level thereby providing some margin to account for any possible differences in ESD simulator outputs. Regards, Manny Barron On Mon, Oct 14, 2019 at 6:39 PM Bill Owsley < [email protected]> wrote: > My experience, is that all brands, commercial and custom private built, > will all make for different results. > The ESD generators can all make the required waveforms as poorly defined > and tested. > Yet each different brand or model will give different results. > Why ? Incomplete performance definition and verification procedures. > So we test to extremes and build to pass, then no matter what equipment is > used to test, the product complies, so far ! > > > > On Monday, October 14, 2019, 03:42:00 PM EDT, doug emcesd.com < > [email protected]> wrote: > > > Hi Montara, > > There are more stories than I can type here. The standard as written is > not very good. We addressed this in the early to mid-1990s and determined > what was necessary. We also did a lot of round robin testing. Probably most > of what you want has been published in the 1990s. Look at the ESD > Association papers from the era. Look for authors like myself (we were all > involved with revising 61000-4-2), Jon Barth, Ken Hall, Hugh Hyatt. > > Everything you need was done back then and rejected by the EU members for > various reasons that I do not consider valid. > > Sent from my iPhone > IPhone: 408-858-4528 > Office: 702-570-6108 > Email: [email protected] > Website: http://dsmith.org > ------------------------------ > *From:* Monrad Monsen <[email protected]> > *Sent:* Monday, October 14, 2019 9:43:54 AM > *To:* [email protected] <[email protected]> > *Subject:* [PSES] Any Different Results in ESD Testing when Changing > Brands of ESD Simulator (IEC 61000-4-2) > > > Hi! > > Does anyone have any stories that can be shared of a product getting a > different ESD test result when changing the brand/model of ESD simulator? > > > > I am a member of the US Technical Advisory Group (TAG) for CISPR/I > international standards committee (Electromagnetic compatibility of > information technology equipment, multimedia equipment and receivers). > There is a proposal that SC77B begin work on changes to IEC 61000-4-2 (ESD) > to improve the ESD waveform verification (some call this “calibration”) > because under today’s rules different simulators create different levels of > high frequency signal content which some believe is the primary reason for > different test results. Some believe that the IEC 61000-4-2 waveform > requirement fails to include any evaluation of the slope (dV/dt or dI/dt) > of the impulse, and that uncontrolled parameter directly affects spectral > content. I would like to know if anyone has experienced any actual ESD > test result consistency when using different Brand/model ESD simulators > even though they are all calibrated simulators under today’s rules. > > > > I admit that our company uses the same brand & model ESD simulator as > local labs, so I have never observed this issue myself. My initial > preference is to not add cost to testing and avoid forcing labs to buy new > ESD simulators, but perhaps this cost is warranted if there are actual wide > variations in ESD test results depending on the brand of ESD simulator. > > > Thanks. > > > > Monrad Monsen | Hardware Compliance Strategist > Phone: +1.303.272.9612 > Oracle Market Access & Hardware Compliance Strategy > 500 Eldorado Blvd | Broomfield, CO 80021 > > > - > ---------------------------------------------------------------- > > 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 < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - > ---------------------------------------------------------------- > > 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 < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - > ---------------------------------------------------------------- > > 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 < > [email protected]> > > All emc-pstc postings are archived and searchable on the web at: > http://www.ieee-pses.org/emc-pstc.html > > Attachments are not permitted but the IEEE PSES Online Communities site at > http://product-compliance.oc.ieee.org/ can be used for graphics (in > well-used formats), large files, etc. > > Website: http://www.ieee-pses.org/ > Instructions: http://www.ieee-pses.org/list.html (including how to > unsubscribe) <http://www.ieee-pses.org/list.html> > List rules: http://www.ieee-pses.org/listrules.html > > For help, send mail to the list administrators: > Scott Douglas <[email protected]> > Mike Cantwell <[email protected]> > > For policy questions, send mail to: > Jim Bacher <[email protected]> > David Heald <[email protected]> > - ---------------------------------------------------------------- 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 <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
