Conformity Magazine - August 2008 - (Page 30)

The most significant change here is in the unpowered product test, where there is now an explicit requirement to prove that the ESD handling stress has not degraded components providing other EMC performance criteria, such as capacitors that are ensuring emission or immunity performance. What this requires is that only that product that has the unpowered ESD test should be used for the rest of the EMC performance testing. While I can see the sense in this regime, ensuring that the other EMC performance as well as the functional performance is not degraded by handling can be difficult to apply in a product test plan. Further, it is not uncommon to submit several ESAs for testing so that all the different tests can be conducted simultaneously to save time, but this will not be possible under the new unpowered product test. Furthermore, a failure in connection with a radiated emissions issue, for example, would have to be re-tested for handling ESD To the test service industry and test equipment suppliers, the changes found in ISO/FDIS 10605:2008 will have little impact, and the test equipment used today for automotive ESD testing is suitable. The greatest impact occurs to the producer of ESAs, where the quantity of testing will be increased. prior to emissions retesting, in order to ensure the emissions improvement was still ESD immune. Although this is a sensible engineering change to the test regime, it will add significant test costs to the producer and increase the overall quantity of ESD testing being performed, since a handling ESD test should now precede almost every other EMC test. The new standard now includes several photographs showing examples of testing on-vehicle, something that was absent in the current edition, although a diagrammatic line image is provided. Optional Powered ESA Test Case There is a new test specified as an optional test in annex F of the update. The new test is quite a good idea in that it simulates discharges close to the ESA harness (i.e., to the chassis or body). The test places another 0V reference plane below the ESA and its harness, and discharges to this. There are separate discharge levels for air and contact discharge up to ±25kV, and only the 330Ω resistor network is specified. Although I think the test itself is a good representation of the in-vehicle situation, the implementation of the test is overcomplicated. How is a 25kV contact discharge to the ground supposed to occur? If you are charged to 25kV and holding a metal tool, you will discharge a long time before you come into contact with the vehicle (this is true even for charges as low as 3kV). Consequently, only air discharge should be applied for this type of test. The main problem with this test is that, as an optional test, few producers will specify it (who wants to pay extra for their testing?) and will leave this to the VMs themselves. And, once again, this is a test taken directly from a VM test specification (Daimler-Chrysler in this instance) that uses the 330Ω resistor in the human body model. I suspect that this one VM has had an issue with a product that this type of test has been able to identify, and are trying to get all VMs to adopt the same by having it incorporated into this ISO standard. Minor Alterations Among the other minor changes found in the updated ISO 10605, the ground plane (or ground reference plane, GRP, and horizontal coupling plane, HCP) can now be only 0.25mm thick rather than the 1mm thickness previously specified (although I’ve never come across anyone using such a thick metal sheet in practice). The minimum area is also better defined at 1.6m x 0.8m, rather than the rather indeterminate 1m2. 30 Conformity AUGUSt 2008 http://www.amphenol-aerospace.com/filtercatalogs http://www.amphenol-aerospace.com/filtercatalogs http://www.amphenol-aerospace.com http://www.amphenol-canada.com

Table of Contents Feed for the Digital Edition of Conformity Magazine - August 2008

Conformity Magazine - August 2008 Contents Editor’s Note FCC Seeks Comment on Reauction of 700 MHz D Block Commission Cracks Down (Again!) on Junk Fax Marketer Canada Levies Fees for Public Safety Radio Spectrum FDA Issues Guidance on Medical Device Tracking Greenpeace Challenges Video Game Manufacturers The IEEE EMC Society: A Proud History of Accomplishments ESD Open Forum An Update on Changes to the Automotive ESD Standard, ISO 10605 Modeling of Radiated Electromagnetic Disturbances in Automotive Applications Design Issues in Automotive Radio Frequency Systems IEEE EMC Symposium IEEE 2008 Show Preview Exhibitors Buyer’s Guide Product News Most Eco-Friendly Companies Updated Standards List For the EU’s Pressure Equipment Directive Commission Issues Updated Standards List For Directive on Gas-Fired Appliances HHS Releases Fact Sheet on U.S. Imports from China Customs Agents Seize Holiday Lights IEEE PSES Symposium Set for October CPSC Actions in the News IEC Standards Update UL Standards Update Telcordia Standards Update From Our “You Can’t Make This Stuff Up” Department Looking Back: Items from Past Issues of Conformity Product Reviews Advertisers

Conformity Magazine - August 2008

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