Dear Group, There is a big misunderstanding about "verification", "calibration", "daily check" etc. I am member of IEC TC77B WG-9 (ESD). We discussed what we want the user to do and the present opinion is as follows (A new draft of the ESD standard will reflect this position): (1) Formal calibration =============== Every year (or any other interval set by the quality system) a formal calibration of the ESD simulator is done. This requires using calibrated equipment and tracebility. (2) Tests done to gain confidence that the simulator is still within specs =================================================== At intervals totally determined by the user a quick check is done. This does NOT require tracebility. For example, if the user uses a 500 MHz (too slow for an official calibration) scope to check the waveform at one level and one polarity. Now the user compares the waveform from the 500 MHz scope to the a waveform obtained after the last formal calibration. Using engineering judgement, the user can not determine if the ESD generator is probably still OK. What is important to note: Only for the formal calibration calibrated equipment is needed. Typically, this is done once a year. Every other method to gain confidence in the ESD simulator status does NOT have to be traceble. For example, for a quick check (weekly) at some HP sites a system (Has been published in Compliance Engineering) is used that measures the peak current and its pulse-to-pulse variations (using an extremly fast peak detector). Now if the peak current is OK, the assumption is made that the generator is still OK. This assumption is based on the experience that most failures in an ESD simulator will show up as a change of the peak current. The method has been accpeted by A2LA, DATech and other accreditation agencies. Still, this is not an official statement by IEC. Regards David Pommerenke
-----Original Message----- From: Michael Taylor [mailto:[email protected]] Sent: Monday, February 25, 2002 12:32 PM To: 'Kevin Harris'; '[email protected]'; [email protected] Subject: RE: ESD Generator confidence test We looked at the unit and almost purchased one. However, we discovered the annual cost to ship it back to Belgium + the calibration costs amounted to almost 78% of the purchase price. It just was not economical. If someone in the USA could calibrate it at lower cost it's a great product. Michael Taylor Still shoveling snow in Colorado -----Original Message----- From: Kevin Harris [ mailto:[email protected]] Sent: Monday, February 25, 2002 7:59 AM To: '[email protected]'; [email protected] Subject: RE: ESD Generator confidence test Vic, A couple of years back at the Seattle IEEE EMC show a go/ no go confidence tester for static testing was discussed and demonstrated. I'm not sure if that still is commercially available but if you email Ivan Hendrikx at [email protected] he will be able to tell you more I'm sure. Best Regards, Kevin Harris Manager, Approval Services Digital Security Controls 3301 Langstaff Road Concord, Ontario CANADA L4K 4L2 Tel: +1 905 760 3000 Ext. 2378 Fax +1 905 760 3020 Email: [email protected] -----Original Message----- From: [email protected] [ mailto:[email protected]] Sent: Monday, February 25, 2002 9:00 AM To: [email protected] Subject: ESD Generator confidence test The ESD standard IEC 61000-4-2 gives details for the manufacture of a current target, used for verifying the ESD waveform. I appreciate this could be used as a confidence check before administering the test, but does anyone have another approach that they would be willing to share. Many thanks Vic Gibling EMC Engineer Raytheon Systems Limited ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mai
