what the heck does that mean? was he of the wrong nationality too? maybe crippled?
From: Daniel Forrest [mailto:daniel.forr...@at.flextronics.com] Sent: Thursday, February 13, 2003 1:21 AM To: 'Richard Hughes'; 'Stone, Richard A (Richard)'; 'Brent DeWitt'; emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety I can only presume that both the EMC Directive and the LVD will never account for the fact that the guy was American. From: Richard Hughes [mailto:rehug...@nortelnetworks.com] Sent: Wednesday, February 12, 2003 4:35 PM To: 'Stone, Richard A (Richard)'; 'Brent DeWitt'; emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety Richard, I think that you may be getting things mixed up. The aspect of Functional Safety that was being discussed is when a safety hazard results from the equipment under consideration being exposed to a level of em radiation greater than that which it was designed for. We are not discussing whether it is possible to increase emissions due to a single fault. In fact this topic has been discussed in the LVD Working Party with a particular situation as follows. The issue was caused by an electronically controlled bread-toaster. The consumer had put his newspaper on the (cold) toaster - presumably due to lack of space in his kitchen. He then received an incoming call on his mobile 'phone, which turned his toaster on (due to lack of immunity). The hot toaster then set the newspaper on fire. Personally, I am not convinced that simply carrying out single fault testing will ensure that there is no safety hazards in all cases. It really depends on the design of the electronics in the equipment. Perhaps the design requires two separate transistors to be turned on by two independent microprocessors in order to create some kind of hazard. However, if the immunity of the system is poor then both of these microprocessors could generate signals that turn both of these transistors ON. Of course, this is just a thought experiment and I have no personal experience of this being a problem in real life. With safety it is very difficult to prove that a hazard can not exist by inspection of the design when - as Ken Javor said - "Genius has its limits, but ignorance has none." While I am on line, I never said that the content of the article was technically good, only that it was interesting! It has certainly caused a stir. Regards, another Richard. From: Stone, Richard A (Richard) [mailto:rsto...@lucent.com] Sent: 12 February 2003 13:23 To: 'Brent DeWitt'; emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety its not the fault of a component that concerns me.... For EMI interference,just running normal., a very loud radiator could interfere with something else, wheel chair controller, as mentioned, thats why testing is critical...now for the fault! Not an expert, but a component fault,typically may make something not work, but worse emissions as a result? anyone have information on this event? thanks, Richard, From: Brent DeWitt [mailto:bdew...@ix.netcom.com] Sent: Tuesday, February 11, 2003 9:39 PM To: emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety Gregg, As an EMC engineer and a member of the IEC committee that wrote the 2nd edition of IEC 60601-1-2, I find your "challenge" interesting. First, I have to say I was not impressed with the referenced article. Facts were played a little bit too loose for my preferences. That said, I strongly believe that EMI is an inseparable portion of product safety. You mention that "EMC interferes" and I agree. When it interferes with a wheelchair controller and drives the patient into traffic or causes an infusion pump to triple the drug delivery rate, it can kill. I don't believe I have enough product safety experience to say if those same failures could have been caused by single component faults, but I suspect that a real world examination of the product has a significant possibility of missing the single component that was effected. I can say from 15 years or so experience that it takes much less than a microwave oven to cause medically critical control electronics to misbehave. Regards, Brent DeWitt Datex-Ohmeda Louisville, CO From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Gregg Kervill Sent: Tuesday, February 11, 2003 12:14 PM To: 'Richard Hughes'; 'drcuthbert'; emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety I fully agree with Richard Hughes - it is an interesting article but those of us who have conducted "Flight Safety" work will find it VERY weak is its content and treatment. Whilst EMC interferes (unless you are sitting in a microwave oven) - it is Product Safety (or the lack thereof) that kills! Furthermore I challenge anyone to demonstrate that the EMC related fatalities could not have been caused by a single components failure. Best regards Gregg From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Richard Hughes Sent: Tuesday, February 11, 2003 11:01 AM To: 'drcuthbert'; emc-p...@majordomo.ieee.org Subject: RE: EMC-Related Functional Safety Dave, As you say, an interesting article. Note however that it states in regard to the LVD that: "The Low Voltage Directive (LVD) Although the LVD (73/23/EEC, modified by 93/68/EEC) is generally reckoned to cover functional safety, there are no words in its text that specifically mention it - never mind EMC-related functional safety" While this is accurate as far as it goes (and remembering that the Safety Objectives of the LVD were published in 1973), it could give people a false impression. The February 2001 version of the Commission publication "GUIDELINES ON THE APPLICATION OF COUNCIL DIRECTIVE 73/23/EEC" states: "The Commission interpret that all electromagnetic aspects relating to safety including functional safety are covered by the LVD." Many of you will be aware that a revision to the LVD is underway. At the present state of discussions the draft "essential requirements" are far more detailed than the old "safety objectives" and certainly include this issue. Of course, what the final text will be is not known with certainty at this time. Regards, Richard Hughes Personal opinions only, of course. -----Original Message----- From: drcuthbert [ mailto:drcuthb...@micron.com] Sent: 10 February 2003 19:27 To: emc-p...@majordomo.ieee.org Subject: EMC-Related Functional Safety
