I fully support Lacey's views about performing some immunity testing on the products, in order to improve their reliability.
Long before FCC/EU implemented EMC requirements on the electronic products, IBM had formulated emissions and immunity standards for their products. Even now some of the IBM standards are tougher than the FCC/EU standards, while a few others do not figure in EU requirements. The only purpose for these internal standards is to make sure that customer has no cause for complaints, even when the equipment is not used as per the manufacturer's recommendations. We keep on devising new tests to emulate the working of our products under severe stress conditions, some of which may be caused by the poor quality of auxiliary equipment used by our customers. Again, if these extra requirements are designed-in, the cost to the company is extremely low. All it needs is the awareness in the designers to take these requirements in to consideration at the early design stage. Bigger companies like IBM can afford to have a dedicated person overseeing these needs, but then they also have lot more products. Smaller companies can train there design engineers in EMC practices. Also, there are inexpensive tools, which although not perfect, can provide big help in making first prototype almost right. All this certainly saves you big bucks at the test labs, and putting retrofits to mitigate EMC problems, once the product has been built. As Lacey has pointed out, we are going to see more susceptibility problems in household equipment as our home PCs become faster and faster, and microprocessors are used in increasing numbers of household appliances. Regards, Ravinder PCB Development and Design Department IBM Corporation - Storage Systems Division Voice : (408) 256-7956 T/L : 276-7956 Fax : (408) 256-0550 Email: ajm...@us.ibm.com *************************************************************************** Always do right. This will gratify some people and astonish the rest. .... Mark Twain "Lacey,Scott" <sla...@foxboro.com> on 03/04/99 05:44:33 AM Please respond to "Lacey,Scott" <sla...@foxboro.com> To: Chris Dupres <chris_dup...@compuserve.com> cc: emc-p...@majordomo.ieee.org (bcc: Ravinder Ajmani/San Jose/IBM) Subject: RE: New EMC requirements proposed for IEC60335 Chris Not to beat a dead horse, but: While your observations on the political side are very interesting and all too true, I still stand by my comments regarding immunity testing of "fly-by-wire" (100% electronic vs. electronic/electromechanical controlled) products. These products are potentially far more dangerous than most people realize. The tremendous flexibility of microprocessors is often abused by lazy or sloppy designers, who tend to mask out problems in software rather than correct very real and serious hardware problems. This is especially common at smaller firms, of which I have worked for many (under temporary contract). On many occasions I have had to "go to the mat" in design meetings in order to win a couple of days reprieve to find and fix problems prior to a "software solution" being implemented. The problems almost always were relatively easy to correct, once diagnosed correctly. Some could have been very dangerous under the wrong circumstances if left uncorrected. If all immunity testing requirements were struck down tomorrow, I would still want to perform some level of testing on this type of product. To not do so is to expose yourself to tremendous legal liablilities in the future. Many immunity tests may be improvised in order to get a feel for how the product performs under duress. The point is not that consumer products must always behave flawlessly, only that no dangerous conditions result. Scott > -----Original Message----- > From: Chris Dupres [SMTP:chris_dup...@compuserve.com] > Sent: Wednesday, March 03, 1999 6:29 PM > To: Lacey,Scott > Cc: emc-pstc > Subject: RE: New EMC requirements proposed for IEC60335 > > Hi Scott. > > You wrote: > < It's sometimes all too easy to forget WHY we perform these tests. While > we are trying to comply with written requirements in order to "pass", we > are also trying to ensure product > performance in the real world,> > Time for my favourite hobby horse again... > > Going back even further than your memory, back in fact to 1972, the Treaty > of Rome in Europe. This was when the Euro Nations decided to get into a > single trading bed and knock down barriers to trade within Europe. > > In Europe, we called it the Common Market. In the US it is often called > 'Fortress Europe'. > > Whatever, as a result of this treaty, all Euro Nation States had to follow > Directives, one of which was raised in 1989, the EMC directive, which sort > to regularise EMC performance within Europe. The purpose of this > Directive, I need not remind you, is to ensure that no Euro State, or any > other state for that matter, couldn't steal a trading advantage by making > their equipment cheaper by building to a lesser standard of EMC > performance. I suppose it was levelling the playing field, such that > everything had to meet a minimum standard. Since then the standard > required is slowly getting stiffer, but whether this improves the lot of > the Euro Proletariat or not, I have my doubts, but sure as hell the sales > of filters, screening and EMC testing services has gone through the roof. > > I could ask, "Who are the CISPR committees, who told them what constituted > a suitable EMC performance? Who voted them into power, who let them put > the price of my TV up?" Who told the BS and DIN people to make my life > more complicated and more expensive by constantly making the EMC > requirements more difficult to meet? I don't remember voting for them... > But as I earn my living supporting exactly that business, it would be > churlish to do so, so I wont just now. > > If you read the Directive, you will note that terms like 'Removal of > barriers to trade', and 'free movement of goods across borders' etc. are > mentioned so often it gets boring. But not once does it say anything > about > making the world a less EMC active place, or anything about improvements > to > the environment or living quality by the reduction of interference. > > No, the EMC Directive is a financial/political package, the politicians > who > approved the Directive's publication wouldn't recognise an EMC if it fell > on their foot. Our activities in trying to achieve Euro EMC standards is > merely to meet the political aspirations of a European Economic Area, and > so far that seems to at least stopped big wars in Europe for the last 50 > years or so. Maybe that's the real reason for all this. > > Another self opinionated twopence worth from a tired, cynical, aging EMC > hack. > > Chris Dupres > Surrey, UK. > > p.s. Has anybody heard about the Bad Haircut Directive? > > --------- > This message is coming from the emc-pstc discussion list. > To cancel your subscription, send mail to majord...@ieee.org > with the single line: "unsubscribe emc-pstc" (without the > quotes). For help, send mail to ed.pr...@cubic.com, > j...@gwmail.monarch.com, ri...@sdd.hp.com, or > roger.volgst...@compaq.com (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators). --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
