Hi Richard, Very eloquently stated, and accurate.
OK, with that said, I guess I’m all done stirring up the EMC pot! I just thought this was such a great example – it is hard to see such a device affecting immunity characteristics, the requirement in the guidelines to cover every possible scenario seems pretty much impossible to achieve, and it’s very difficult for me to see a clear distinction between a component and a system for a memory module - ‘it just smells like a component to me’. I still think that a sound, defensible engineering rationale can be made to support the case that a memory stick does little to affect the immunity characteristics of a desktop PC. I reluctantly agree that it could POSSIBLY (not likely) affect the unintentional emissions of a desktop PC. I strongly agree that there are marketing and customer confidence advantages to placing the CE Mark on such a device, even if the requirements are somewhat unclear, and may have some ‘wiggle room’ there. I totally agree that the most conservative course here is to apply the EMCD in full. (did I encompass everybody’s posts here?). And as always, if in doubt, TEST!! One last thought – I would think that the cost of a full compliance test suite amortized over the expected sales volume of a memory device should be somewhere down in the noise floor in terms of a per-unit added cost…. I usually don’t add any ‘disclaimers’ to my posts – I tend to just say what I think, and take my lumps when I’m way off base – but maybe in this case, I should, since I do work at an EMC test lab: THE OPINIONS EXPRESSED HERE ARE MY OWN, AND NOT THAT OF MY EMPLOYERS. THE OPINIONS EXPRESSED ARE JUST THAT; I AM NOT A RECOGNIZED EMC EXPERT (far from it), JUST AN OPINIONATED YOU-KNOW-WHAT. Cheers, all – very stimulating discussion! Doug Massey Product Safety Engineer Advanced Compliance Solutions Ph. (770) 831-8048 FAX (770) 831-8598 Visit our web home at <http://www.acstestlab.com/> http://www.acstestlab.com From: [email protected] [mailto:[email protected]] Sent: Tuesday, November 11, 2003 6:55 PM To: [email protected]; [email protected] Subject: Re: opinions, please Doug, Guidelines, whether relating to the LVD, EMC Directive or whatever do not have the same 'weight of law' as the requirements of the directives themselves. Strictly speaking, Directives are not themselves law. They are first and foremost instructions to individual Member States (think countries) to pass national laws that are consistent with the provisions of the Directive. Please be aware that EU is a still a collection of separate countries, each with its own government, legal system and means of policing compliance. By no means is the EU a mirror of the USA (and I not making a political statement here, lest people infer otherwise). What we have then is a system of creating a set of more or less harmonious national laws based on a particular Directive. Guidelines are what they say they are. They are not law and national courts can take heed of them, or not, as the case may be. Of course, when it comes to matters of law you are ultimately talking about having to convince a judge or a jury, neither of whom are likely to understand the finer points of EMC! Therefore, many manufacturers prefer the warm-fuzzy feeling that comes from complying with the guidelines, irrespective of the fact that they are voluntary. Regards, Richard Hughes Safety Answers Limited In a message dated 11/11/2003 22:00:36 GMT Standard Time, [email protected] writes: It is hard to argue with the Guidelines! (although, do the EMC Guidelines have the same weight of law as the EMC Directive?)
