Some food for thought . . . It can depends what you mean by 'system'. Here's two examples: 1) A system can be a single product (like a PC) that can contain 'components' that are CE compliant (power supply, modem card, motherboard). 2) Or a system can consist of several products - a workstation, a disk server, a printer. In example '1' CE + CE does not necessarily equal CE. When put together the 'system' may radiate. The individual items may have been tested in a certain configuration which the integrator may not be mimicking. There was an instance in the UK where a PC manufacturer was fined by Cardiff Trading Standards (who routinely patrol for EMC Directive - amongst others - violations). THe manufacturer of that PC used the CE + CE = CE approach. But when the unit was actually tested, it failed miserably. For example '2', you may be able to get away with CE + CE = CE. With this type of 'system', the 'modules' themselves were most likely tested in a configuration that the system 'manufacturer' (integrator) would most likely be assembling. Typically this is what happens with home PC 'systems'. Those that assemble such a 'system' at home, for home use don't have to demonstrate compliance. But then again, the home user is not bundling the package for resale. In that case I, as a manufacturer would evaluate the system because it is ultimately my responsbility in ensuring that MY end product (the bundled 'system' with a model number that I generated) meets the requirements. John Juhasz Fiber Options Bohemia, NY
-----Original Message----- From: Canio Dichirico [mailto:cdich...@eso.org] Sent: Monday, March 27, 2000 7:31 AM To: IEEE EMC List Subject: Is the "modular approach to EMC" the same as CE + CE = CE? Hi All! The designer/manufacturer of a (prototype) system has recently exposed to me the following argument. If the system is built out of subsystems that are CE-marked, the complete system may be considered compliant with the EMC Directive 89/336/EEC. The designer stated that this is possible on the basis of the "modular approach to EMC". In order to understand this argument I read the paper "Update on the European Union's EMC Directive", appeared on the European Edition of Compliance Engineering - 1999 Annual Reference Guide. In this paper one may read that "For systems and installations ... either a system or a modular approach may be used to demonstrate compliance. The TCF [Technical Construction File] route is thus not required for verifying a system and/or installation if all subunits and subsystems comply with the EMC requirements (modular approach), presuming that the referenced standards are relevant for intended environments and that installation guidelines are followed." Does what I read on Compliance Engineering confirm what declared by the (prototype) system designer? Which are the "installation guidelines" that the paper quoted above is referring to? Which are the differences, if any, between the "modular approach" and the "equation" CE + CE = CE? I remember reading in this forum (plenty of times) that CE + CE does not necessarily equal CE. Any replies or comments are welcome. Thank you all in advance! Canio Dichirico European Southern Observatory Technical Division - Electronic Systems Department Karl-Schwarzschild-Str. 2 D-85748 Garching bei München Tel. +49-89-3200 6500 Fax +49-89-320 23 62 email: cdich...@eso.org <mailto:cdich...@eso.org> website: www.eso.org <http://www.eso.org>
