I have read a part of the IEE guide mentioned below. What I have read on a paragraph by paragraph basis is fine, but I find the overall philosophy deeply troubling. The tone of the document is that the manufacturer is responsible for all uses or misuse of the equipment he sells in concert with every other type of equipment made or that might be made at some time in the future. This document is a trial lawyer's dream. It takes us from a society in which a sale was deemed a transaction of mutual benefit between equals to a society in which an Omniscient Producer must cater to the needs of an ignorant, childlike Consumer, and in direct corollary, any misuse of any product by any consumer is deemed proof that the Omniscient Producer was profiting by taking advantage of a helpless victim. I realize this document merely reflects this prevalent view, but the idea that an Industry group would provide such a smoking gun for some trial lawyer to use in defense of some poor misled swindled consumer is, to say the least, troubling. To say that Industry standards don't go far enough, that it is the responsibility of the Producer to be able to determine all possible environments and failure modes that might ever occur is placing an impossible burden and any rationale entity, upon reading this document will immediately cease production of anything that could conceivably ever malfunction in anyway whatsoever.
Case in point: A friend of mine bought one of these 2.4 GHz remote miniature video cameras with integral IREDs and is able to monitor his infant twins from his own bedroom, even in the middle of the night with no lights on in the twins' bedroom. Suppose that 2.4 GHz link is disturbed in some way and he misses something important happening in that bedroom. Is the manufacturer of that video system responsible for any ill that then befalls my friend's twins? I think not. But this safety guide says yes, and places the manufacturer at risk. ---------- From: cherryclo...@aol.com To: emc-p...@majordomo.ieee.org Subject: Re: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date: Wed, Jan 2, 2002, 9:49 AM Once again, John, you seem to be trying to give a negative impression about the IEE's guide on EMC and Functional Safety (which you now admit you haven't read) instead of simply saying what it is that you think is wrong with it. Of course I am passionate about the IEE guide - my colleagues and I spent a long time working on it! When I discovered you were criticising it to the emc-pstc of course I had to respond - but I was not (and am not) trying to defend the guide, merely trying to find out just exactly what it is that you (and your silent 'equally senior experts') don't like about it so I can get it improved. I am sorry if my wordy emails give the wrong impression - the simple fact is that I always write too much (as any editor who has had an article from me will confirm!). Once again I ask you - and everyone else in the entire EMC or Safety community world-wide - to read the IEE's guide and let me have constructive comments about how to improve it. You can easily download it for free from www.iee.org.uk/Policy/Areas/Electro (- you only need to download the 'core' document for this exercise and can leave the nine 'industry annexes' for later criticism). I'll make it easy for anyone to comment even if they haven't read the Core of the IEE's guide.... ...the guide is based on the following engineering approach, explicitly stated at the start of its Section 4 and duplicated below. ***** To control EMC correctly for functional safety reasons, hazard and risk assessments must take EM environment, emissions, and immunity into account. The following should be addressed: 1) The EM disturbances, however infrequent, to which the apparatus might be exposed 2) The foreseeable effects of such disturbances on the apparatus 3) How EM disturbances emitted by the apparatus might affect other apparatus (existing or planned)? 4) The foreseeable safety implications of the above mentioned disturbances (what is the severity of the hazard, the scale of the risk, and the appropriate safety integrity level?) 5) The level of confidence required to verify that the above have been fully considered and all necessary actions taken to achieve the desired level of safety ***** Please - anybody and everybody out there - tell me if there is anything wrong with this engineering approach to EMC-related functional safety. Involve experts you know who are not subscribers to emc-pstc too. Please be as detailed as you can be. If I receive no constructive comments about the above 5-point approach by the end of January I will assume that the IEE's guide is on the right tracks and will not need major revisions. You can send any comments to me via emc-pstc or directly to keith.armstr...@cherryclough.com or cherryclo...@aol.com. Interestingly, my reading of IEC/TS 61000-1-2 leads me to believe that it follows the same general approach as the IEE's guide. Regards, Keith Armstrong In a message dated 31/12/01 21:58:43 GMT Standard Time, j...@jmwa.demon.co.uk writes: Subj:Re: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date:31/12/01 21:58:43 GMT Standard Time From: j...@jmwa.demon.co.uk (John Woodgate) Sender: owner-emc-p...@majordomo.ieee.org Reply-to: j...@jmwa.demon.co.uk <mailto:j...@jmwa.demon.co.uk> (John Woodgate) To: emc-p...@majordomo.ieee.org I read in !emc-pstc that cherryclo...@aol.com wrote (in <17c.18c06c2.296 20...@aol.com>) about 'EMC-related safety issues', on Mon, 31 Dec 2001: > Quite a number of EMC and Safety experts took part in creating the IEE's > Guide on EMC and Functional Safety, including a lawyer who specialises in > high-tech issues. You will find their names listed at the end of the 'core' > of the guide (downloadable from www.iee.org.uk/Policy/Areas/Electro). Many > of these experts also involved their colleagues and others so we got a very > wide spread of opinion. My comments referred to the IEC work, specifically verbal reports from people involved. You will have noticed that the work culminated in a TS, not a standard as originally envisaged. That in itself may be an indication of certain difficulties in its passage through IEC. I think that a passionate defence of the IEE document (which I have not studied, so will not comment on) *may* also be an indication that there is more emotion surrounding this subject than is desirable. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero.