An emergency over-ride could be a simple as turning off the ignition, but I'd add that it is not always that simple when a failure catches the operator by surprise while in highway traffic.
I think that all safety-critical functions (like accelerator or braking) should be single-fault tolerant, but may not always be easy to implement. _______________________________________ _____________________________________________ Ralph McDiarmid | Schneider Electric | Renewable Energies Business | CANADA | From: John Woodgate <[email protected]> To: [email protected] List-Post: [email protected] List-Post: [email protected] List-Post: [email protected] Date: 02/24/2010 12:59 PM Subject: Re: [PSES] Toyota ________________________________ In message <[email protected]>, dated Wed, 24 Feb 2010, Richard Nute <[email protected]> writes: > >> There do seem to be some very odd features about this incident. Why >> wasn't the CHP officer making the 911 call, instead of the hysterical >> person who did? > >The CHP off-duty officer was driving with his family >in the auto-dealer courtesy car. > >I guess he was pretty busy trying to control the car >(at 160 km/h), so his wife made the call. (I think >there's a web site where you can listen to the call.) I don't know; no-one presumably knows. but I expect a CHP officer to be used to 160 kph, and also to know how to stop a runaway - as I posted earlier about the signs at Porlock Hill in bygone days. > >> However, that is beside the point. Now that the focus has turned to EMI >> being involved, and the practical impossibility of testing for all >> conceivable EMI threats, I think we are looking towards a *mechanical* >> emergency throttle closer and/or fuel cut-off. > > >Have you ever had a computer lock up? Was it due to >EMI? Re-cycle power and everything runs normal. And >no trace to the cause of the lock-up. Precisely: and since causes of such effects are legions - so that testing for all of them is simply impracticable, we had better settle for 'gas by software' being inherently not reliable enough, just like triacs are not regarded as reliable enough as main power switches, we had better have an emergency manual override. -- 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 <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/ <http://www.ieee-pses.org/> Instructions: http://listserv.ieee.org/request/user-guide.html <http://listserv.ieee.org/request/user-guide.html> List rules: http://www.ieee-pses.org/listrules.html <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]> ________________________________________________________________________ This email has been scanned for SPAM content and Viruses by the MessageL abs Email Security System. ________________________________________________________________________ - 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]>
