In message <[email protected]>, dated Wed, 17 Feb 2010, "Grasso, Charles" <[email protected]> writes:
>I agree with Johns comments. I just hope that he was not ill-advised. >Looking at the title its my impression that Keith is forcibly making >the case >that EMI and/or manufacturing practices caused this crash. This is a >dangerous case to make considering >that there is no evidence of what caused the crash. I think that what he is saying is that normal EMC thinking isn't appropriate for safety-critical systems, and this principle is indeed embodied in IEC 61508 series. But the subject is quite difficult to grasp, as one can see from the number of 'explanatory' parts in the series. There is also: IEC/TS 61000-1-2 ed2.0 (2008-11) Electromagnetic compatibility (EMC) - Part 1-2: General - Methodology for the achievement of functional safety of electrical and electronic systems including equipment with regard to electromagnetic phenomena There is indeed at present no evidence in the public domain about cause or causes. Some EMI leaves no trace: some does. The evidence from people involved in an incident must be treated with great caution. Driving tuition might well include advice (not necessarily a demonstration!) of what to do in a 'runaway' situation, which might occur for any one of many reasons not connected to electronics. In south west England there is a well-known very steep hill (Porlock) and at one time, when brakes were generally none too good, there were notices that said 'If it runs away, steer for the bank.' > >As John points out ? one can get mechanical ?latch-up? too. I don't know that the Rover problem was exactly latch-up, but I did find in on a 'special' car that an acquaintance had built in the days of our youth. If you pressed the throttle pedal hard, the mechanism toggled into an unintended configuration and the throttle would only close part way. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK I should be disillusioned, but it's not worth the effort. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
