Re: Bendable circuit boards
Do a search with www.google.com for flex circuit. Worked with this type of thing over 15 years ago. This particular technology has a long mature history. Started with having to fold-up and pack circuits into tight spaces in missles. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Undervoltage/Overvoltage Effect on Household Appliances
I'll add my 2 cents and say that any ac motor which goes into lo-line stall or hi-line saturation. I.e. refrigerators, air conditioners where the compressor can be damaged. A brownout causing the motor to stall drawing more current than normal and overheating. Or at a high enough level where a motor goes into saturation. Then, it can draw enorous currents and overheat. Switchers can tend to go nuts in lo-line causing it to draw a high current with a high load. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: A Different Kind of EMC Problem
If the problem were emissions, the interference would be very audible with the radio station off the air. Just a rambling thought pattern ... I'm not sure I necessarily agree with this. If the radio carrier drops off, the front end stage and intermediate stages aren't carrying an rf signal through to the demodulation stages. If 60 Hz is indeed getting into the radio to the demodulation stage by way of radiation, it's not doing it through the front end or intermediate stages. Those filter stages wouldn't carry something as low as 60Hz. Therefore, you may very well hear nothing with no station carrier present. 60Hz most definitely will be heard if it's inductively effecting the radio if the station is broadcasting or if it's off. That I agree. And if the induction is sufficiently high, you may well hear the 60Hz through the speaker when the radio is even turned off. This is one of the ways which they used to sweep a room for listening devices. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Hot chassis ...
Anyone have any fresh ideas on how to improve the overall chassis ground integrity of a hot box? Let me explain - standard off the shelf box, about 4U high, with 2 redundant AC power supplies. Bottom and sides are one piece folded up, top cover is screwed down. Primary ground comes through by way of separate disconnectable ac line cords to each supply. Both supplies are plugged into a power supply housing that's screwed down to the chassis. In terms of safety, the grounding is acceptable. In terms of emi though, it seems the grounding is lost for lack of a better word between line cord and chassis leaving the rest of the box 'hot'. From the power supply housing out to power cord, the grounding is controlled by the vendor product to which I am not privy recommending any changes. Frequencies in emissions can be isolated to this or that crystal or board, etc ... But, the overall profile is a wideband high noise level. Huge ground noise profiles on some boards nearly identical to the noise profile on the chassis. Actually just about anywhere on the chassis. In other words, what I see on the grounds of boards is nearly as high as what I see on the chassis. Anyone? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: grounding schemes EMI
Hi Dave, I've had this type of discussion at a previous telco company and the only explanation I ever received regarded ground potential differences between equipment through the mains (as we have discussed in a previous thread). And I always seemed to win by saying that if everything was chassis grounded, then that would be the path of least resistance anyway. At this other company, we shifted from isolated grounds to everything grounded to the chassis and I never saw any of the problems the designers said would happen. In fact, immunity robustness increased. I'll admit that this was with a limited number of products. And I'm sure others here may have different exeperiences. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Ground potential differences
I've no publications, but I did have personal experience with the more destructive results with ground potential differences. At another company, I witnessed the insulation of a coax cable melting after being connected between equipment in a lab where I worked. The problem being a difference in ground potential of 15vac. That in and of itself wasn't the problem. The amperage capacity through ground of the mains system was the culprit. Circa 1983 or so. Turned out that the building was supplied by two electrical substations at opposite ends of the building. And for some strange reason, the substations each shared about half the outlets in the lab. And the potential difference was caused by the electricians connecting to slightly different points on the transformers for ground. The electricians were told and were able to fix the problem. And as far as anything in the field showing a similar problem, I have only dealt with one such instance. And relating the substation transformer ground tap story fixed it for them. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Ethernet Radiated Emissions
[ Neven wrote ] You are seing a spectrum of MLT3 signal, which is 100 Mbit coding. [ John wrote ] Pardon my naivety, but how does '100 Mbit' relate to frequencies of 30 and 60 kHz? Is this 100 Mbit per week? (;-) Could be plenty. I'd guess is something to do with either jitter and/or PLL recovery. That alone I've seen down in the Khz range. And I've seen it do a crude type of FM modulation within a chip to show up as side bands like a picket fence all up and down the spectrum. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
EMI supression for fiber-optic thru-hole ...
Situation: 0.5 inch (13mm) diameter hole punched in a metal chassis through which is passed a fiber-optic connector. Once the connector has been passed thru the hole, you're left with the small diameter cable dangling in a gaping 1/2 inch hole. High noise environment inside the product needs to be contained. Now the cable is of course non-conductive, but is there some emi grommet for the gaping hole in such a construction that plugs up a large diameter hole while at the same time allowing for a small thru-hole? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question regarding something slightly unusual ...
Great apologies with the dyslexia here. Yes, the input is 115-230vac range. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Question regarding something slightly unusual ...
To make things simpler, it could be a stand alone workstation with Recognition approval here in the States and with a GS approval for Europe. I don't want to mention any names but certainly there are well known personal computer mfrs here in the states which routinely get listings on their product with a representative sample without using every single permutation of every single interface card sold out there. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Question regarding something slightly unusual ...
In 20 years, I've never seen this before but that's not saying much. Why would a mfr get a UL recognition approval for a commercial ITE style single phase 155-230vac computer style product but for that same product get the TUV GS mark? Mfr is a stateside company. Product to be used in restricted areas with trained personnel only. But, one that essentially anyone could buy. What's the advantage of getting such a mixed set of approvals? I would assume such a thing would normally get a Listing. Maybe turning the question around for our overseas friends - why would you get a GS mark for your product but only get UL recognition for an ITE computer product when it's normal to get a listing for such a product? And now I'm wondering if with such a device that there's some deviation within the testing as to cause the product to be GS accepted but not with a listing. Regards, Doug (scratching head...) --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: thermocouple welder
Yes. Get a good beefy DC power supply. Attach both leads of the thermocouple to one of the outputs PLUS or MINUS. Doesn't matter. Twist together the leads to be welded. Get a piece of lead that's used in drafters pencils. Attach this piece of lead to the other output of the power supply. Turn on the power supply. LIGHTLY and QUICKLY touch the twisted leads of the thermocouple to the lead a few times. Welding will commence. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
[ John Woodgate wrote ] Oh, come on! There are dozens of safety standards; surely you don't expect me to search and list them all? [ Doug McKean wrote ] You can't possibly be serious. I was more interested in the fact that since this forum is basically ITE, Medical, Test, and SEMI that at least some brief mention of at least one or maybe even two standards of which you're aware without research would suffice. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
[ Doug McKean wrote ] I wasn't aware that primary grounding securements could be used for another purpose. [ John Woodgate wrote ] It depends on the applicable safety standard; some allow it, some don't. [ Doug McKean wrote ] Then since you've got my curiosity up, which ones allow for primary grounding securement to be used for something other than primary grounding. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing through screws.
I wasn't aware that primary grounding securements could be used for another purpose. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Heatsinks and EMI
Heatsinks and EMIAny metallic structure capable of carrying circulating currents will radiate. Ungrounded heatsinks can be particularly susceptible to radiation, or carrying crosstalk from one part of a circuit to another part. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Electric Fence Controllers
Don't ask me where I got this, but ... An electrically dangerous fence is defined in most countries by the energy that the fence can deliver to a 500 ohm load in a second. The IEC is something like 8 joules from fence energizers. Canada and the UK is something like 5 Joules. The fence must pulse once every second. There is an IEC regulation on them, but what it is I haven't a clue. As far as how they relate to the LVD and such, I also haven't a clue. Sorry for all the non-information. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Insulation Distance Between Circuitboard Layers (Safety)
Something's bothering me about this discussion. It's not what people have said that I disagree. Maybe it's to be put in the FWIW department, 1MV breaks down 1 meter of air @ STP. It then follows that 1KV breaks down 1 mm of air. So, that's 1mm AIR/1KV. FR4 has a dielectric factor of about 4.7. That simply means it's 4.7 times stronger than air. Therefore, *in theory* 1KV should in theory break down (1/4.7) mm of FR4, or 0.21 mm of FR4. So, that's 0.21mm FR4/1KV. Now the circuit you're working with, primary or TNV, ... will decide the highest amount of stress during test. If it's going to be 2KVDC, then it's 0.4 mm. If it's going to be 3KVDC, 0.6mm. If it's going to be 8KV with some ESD test, then it's 1.6mm. That's between layers. Wanna put a safety factor of x2 in? The 2KV changes to 0.8mm. The 3KV changes to 1.2mm. Etc ... Something to consider. That's strictly between layers. I'd personally use the air breakdown rule of 1mm/1KV for planes in proximity to vias. And I would always work this out by myself before looking up the standard. And *ALWAYS*, check the standard. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Emissions quick test
I have used a little portable transistor radio for system sniffing of a system with low level freqs and with already knowing the problem freqs. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Grounding in an operating room environment ...
Anyone got the scoop on common grounding practices (either with equipment or with mains grounding) of operating rooms in hospitals here in the US and elsewhere in the world? Is the philosophy to ground everything or float everything with patient connected equipment? Can anyone point to any technical papers regarding ESD in an operating room? Anyone got any horror stories about ESD in the operating room that can be confirmed? Anything out there about ESD induced events in a patient during surgery or with anesthesia? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Radiation formula
Re: Radiation formulaLooks like Ott formulas. Personally I have trouble with those equations. There's obviously some trig functions that should be included in those equations to denote directionality or directivity, or there's some assumption(s) going on not stated. Those equations in general form are highly directional. It is true that one can use those equations to show that the E-field produced by a Hertzian magnetic dipole is proportional to the square of the frequency and that the E-field produced by a Herztian electric dipole is proportional to the frequency, but the magnitudes of the coefficients could erronously show which is of greater concern depending upon the situation and obviously do not give any information about directivity. Personal opinion only. This post is NOT to be construed as a criticism of the great pioneer himself, Mr. Ott. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Domestic 3 meter chamber emissions testing for the world ...
Thanks for the replies. Basically what I'm reading is ... 1) Taiwan does NOT accept 3 meter testing of any sort. They only accept 10 meter testing. 2) Anywhere else in world will accept 3 meter chamber testing, *** BUT *** if the product is challenged in any way AND a retest is performed at another type of site such as a 10 meter site, the results could vary drastically. 3) The vertical height for the antenna for testing at 3 meters could be a problem. If it's a low ceiling room, then you may have some problems. I didn't state that as a condition of my question. Thanks for bringing that up. 4) Be careful of what you do with regard to the differences between the measurement error of the site tested, your margin of error, and the measurement error of an alternate site and a possible different margin of error. Now I've seen numerous arguments concerning the trouble correlating of 3 and 10 meter sites. I concur through my own experience that there is a problem correlating the two. But I have my own reason. Primarily, if the source is more of a point source, then correlation may be 'better' than if the source is a large, or very large EUT. A highly qualified 'better' for sure. But, that's been my own personal experience. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Domestic 3 meter chamber emissions testing for the world ...
What's the bottom line with Class A emissions testing in a 3 meter chamber in the US for emissions approval anywhere in the world? Does the FCC accept such testing for the US? What about for European CE marking under the EMC Directive? How about Taiwan? How about Japan? Been a while since I've had to deal with this issue. Any input here or offline will be appreciated. Thanks in advance. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: ISO 9k/2k relevance
ISO requirement: ISO is NOT law. It is contractual between your company and any one or more of your customers. ROI: If you're company is totally disorganized without procedures and without any sort of feedback system from the field (I doubt you could exist), implenting an ISO system would clean this up. Simply because it's cleaned up with procedures and reports doesn't guarentee your company will be any more successful than a company without it. The ROI with ISO has basically 2 sides to it. 1) ISO is based on what a standard company would do as far as tracking activity on paper. This is supposed to make things repeatable instead of people sitting around trying to figure out, Now just how did we do that? 2) ISO makes it easy for any potential customer who wants to qualify you as a vendor. They can walk in on any day asking for this or that procedure. I'm familiar with ISO 9K. But that's being replace with ISO 2K. ISO 2K has taken away the elements and makes it more difficult with which to comply. There's no subdivisions with ISO 2K as there was with ISO 9K with 9001, 9002, 9003 ... With ISO 2K, if something doesn't apply to your company, you have to justify why it doesn't apply. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Compliance Primer
The last thing you want to do as a compliance engineer under such circumstances is to appear as something of a Compliance Cop. This will drive an impenetrable wedge between you and literally anyone in management. Most probably what James says is correct - the director is looking for either: 1) primarily - ways to cut costs, or 2) secondarily - loopholes. It *might be* good showing someone in this capacity a mountain of standards. But, he more than likely wants to cut to the chase as to *why* you have that mountain of standards. And most likely he'll key into one liners about it being the law. And he'll most likely think something such as, 'okay so it's the law, we all don't obey the speed limit do we?' If he's looking into cost/benefits ratios which he probably is, don't dwell too much on the why we do it, i.e. citing laws verbatum. Dwell on what happens if you don't do it, i.e. penalties, recalls, fines, a European alert system which notifies all of Europe within 3 days about bad product even in countries you don't sell. But most of all - money. It's a common language. And be cool about it. Besides, you're doing HIM a favor by avoiding all that cost and headache. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Tantalum Capacitor Reliability
Been a while, but the voices from a former life in my head are reminding me of something to the effect that rated ripple current of cap is based on a perfect sine wave of ripple. Any other type of waveform can drastically effect that rating. SuperLo ESR caps were used one time to solve such a problem. Not sure if that applies here. The voices are pulling back, now. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Compliance Primer
I used to do seminars internal to companies where I worked on this very subject. Great for people with insomnia. I can pass along the information for a small fee of, say, $20,000 per page ... big grin Regards, Doug McKean - Original Message - From: Scott Douglas To: emc-p...@ieee.org Sent: Monday, July 29, 2002 6:15 AM Subject: Compliance Primer Hi, Does anyone know of any primers on regulatory compliance? Like what compliance is, why we do it, how does one figure out what standards apply to a product, and whatever? Reason I ask is I had these questions posed to me by one of our directors. He wants to learn about compliance. I was caught flat footed. How do you explain what took you 19 years to learn? And that you really don't know as much as you think? I showed him my stack of standards but didn't think that would be a good place for him to start. Looking forward to your comments. Regards, Scott Douglas Senior Compliance Engineer Narad Networks 515 Groton Road Westford, MA 01886 office: 978 589-1869 cell: 978-239-0693 dougl...@naradnetworks.com www.naradnetworks.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Airport Security Immunity Question ...
1. Anyone know the frequencies and levels (E or H) used in airport security for scanning baggage? 2. Anyone have any field reports of anything failing as a result of being scanned or wanded in airport security? 3. Has anyone had to adjust immunity testing to some other level or criteria as a result of airport security they may care to relate in a general way? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: the experts (was: RE: Multiple Product Variants under EN60439)
Well, for my two bits, I've always dealt with agencies as if they're from Missouri The Show Me state. And since specific applications can and do in many instances vary greatly, I have had some test engineers make some general statements but not many. They probably have had their fair share of people who are more unfamiliar than most about standards run off stating this or that as law when they really don't know what they're talking about. I find that true to some extent in any company where I've worked. And my knee jerk reaction is to ask to physically see whatever the issue is on something. It's just part of the job I guess. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Consideration for blind end users ...
Just a curiosity question which came up in a discussion with a sightless person elsewhere ... Q: How well do you think the safety standards cover product use by sightless end users? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: case of units
Don, you're probably right in that it went the other way. My super and I had quite a laugh about it till some poor purchaser told us what was up. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: case of units
Just don't talk to some old purchasing types about k. It doesn't mean base 1,000 in purchasing land. More like base 1,000,000. I ordered some resistors in qty = 1k. It got kicked back to my supervisor because (1) when I multiplied out the final cost, it was wrong and (2) there was no justification for buying one million resistors. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Side Issue: Proximity Cards in Wallets ...
A proximity card reading security system is used in a company, possibly based on the Wiegand Effect. Some of the employees put their security cards in their wallets to have them all the time. When needing access to an area that requires a card, users simply pull out their wallets, swipe the wallet in front of the reader and thus gain access. For those people with cards in their wallets, they do not pull the security card out of the wallet and then swipe the reader. They all swipe the reader with the wallet. A question was posed to me that involved the swamping of the card with a magnetic field to identify the card. The electronics in the card generates a series of pulses from the pulsed magnetic field that when received by the card reader validate or invalidate the card. Is this field strong enough to wipe any magnetic strips on any credit or bank or any of the other types of cards using magnetic strips that may also be in the wallet? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: An ESD question
As has been pointed out by Mr. Woods, humidity is only one of many parameters involved with ESD. And simulating a dry environment in a chamber that's completely lined with metal surfaces might not be sufficient for simulating a dry customer environment. ESD failures at differing levels of voltage is an interesting problem since I've had at least two different types of failures each with entirely different casues. 1. A unacceptable hard ESD failure at a level of say 'x KV' and any level higher is most likely a grounding problem. To lower level 'x KV', look at the grounding setup. 2. A unacceptable hard ESD failure at a level of say 'x KV' but possibly no failure above this until a higher level is reached is more a decoupling problem in combination with a grounding problem. For instance, by a grounding problem I mean ground wire too short, improperly placed, ground wire too small, maybe braid should be used, maybe a strip of copper should be used, and if a braid or strip of copper are being used then maybe they're not wide enough, etc etc ... By a decoupling problem in combination with a grounding problem, I mean the ground problem described above in concert with incorrectly sized decoupling caps, the decoupling caps are improperly placed, leads too long on the caps, wrong sized ferrites if used, improperly placed ferrites, etc etc etc ... Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Some slightly disturbing interview news ...
Times are tough all round but there's no need to make things tougher. Here in Silly Valley, things are tough and I have made some attempts to find a few people jobs in my spare time. These are people I know personally. I'm sure I'm not alone in this venture. I'm sure most if not everyone on this list would also help. One headhunter who called me wanted to know if I was just plain nuts or just some sort of a good guy handing a job offer off to someone I knew who was looking. I told him it was none of his business smirk, just make sure to give so-and-so a call. Which they do. Unfortunately, what I have personally experienced in the past (rarely), and what appears to be happening at least with a few of companies currently is the following ... EMC job opening is posted. Resumes are sent. A few candidates are selected for interviews. Most of the interview centers on questions about how to solve some problems that are being experienced by said company. Then there's a decision not to hire anyone. Purchase req for new hires is closed. All candidates are rejected. A few months later, same company goes through the whole thing again. Only this time, there's a different set of questions to problems all being experienced by said company. Both sets of questions involving how-would-you-solve-this type of problems. I'm sure most of you know where I'm going with this. At the end of the day, the company or whoever in the company, has their solution or solutions. I'm not crying about this. My questions are ... Comes with the turf? Are you surprised to hear such a thing? Not surprised? Has is happened to you? Heard that it does happen but rarely and with some other company somewhere else? Happens all the time? Never happens? You gotta be kidden? So that's what that was all about! Thanks. Yea, but whaddaya gonna do about it? Well, if it does happen, so much the better I don't work there ... Etc ... Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
A little off topic but ... exploding CD's ???
As a matter of safety, has anyone really addressed the issue of the upper speed limit of CDs? Quoted from the following webpage ... http://www.qedata.se/e_js_n-cdrom.htm Introduction But where's the limit? Manufacturers try to outspin each other all the time by selling CD-ROM drives with higher and higher spin ratios. Spin ratios of 2x, 4x, 8x, 16x, 32x, 56x and 64x come in a never ending stream. The CD is forced to rotate faster and faster. At what speed will a CD blow up, and can you do something to prevent it from exploding? ... At the conclusion of the test, the author recommends the following ... Safety Recommendations The committee wishes, after finishing its work, to suggest the following safety precautions. Safe distance to a CD-ROM drive with spin ratio 64x CLV should be no less than 5 metres (15 ft.). All work with CD-ROM units should require safety goggles and protective clothing be worn. CD-ROM drives of the 64x CLV class and higher, should be provided with shrapnel protection of no less than 3 mm aluminium or 1 mm steel. To avoid operator inhalation of CD-ROM particles, CD-ROM drives should be provided with a dust suction fan with suitable filter, or have the fan duct connected directly to the outside air. In addition to the laser light warning label, CD drives should be affixed with another label warning against the hazard of shrapnel, such as the one below: With appropriate labels for exploding CDs. No. This isn't a joke. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Thermal Testing
richwo...@tycoint.com wrote: Do any of you monitor and record component temperatures during safety testing using PCs and data capture I/O cards? If so, what hardware and software to you use? I do any monitoring any temp testing with a Fluke Hydra II and associated PC software. Set up and define probes, start software, dump into an Excel spreadsheet or report. Communication between the Fluke and the PC is done through serial ports. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Be set last
-- Virus Warning Message (on gemini2) Found virus WORM_KLEZ.H in file SK The file is deleted. If you have questions, contact virus-ad...@ieee.org - Thank you! Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Stun Guns on Aircraft.
Gregg, it's bad enough being in Reliability getting on a plane without thinking of the probability of failure, how old the parts are, is there enough redundancy, number of failure free trips etc. etc. etc. Please, let's not go there ... grin Reissue those special air marshall pistols from when they used to carry pistols on planes and put a couple of undercover air marshalls on the plane. Anyway, I'm not sure what kind of stun gun they're talking about - stun guns that are tasers which shoot two metal darts attached by wire to a charge source or the stun guns which have two metal prongs permanently attached to the device which you have to stab at the attacker. In any event both, if accidentally contacted equipment in a cockpit, would cause massive contact currents to circulate across the equipment. I don't think cockpit equipment is put through that much immunity testing. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: A very nice game (an example)
From: T.Sato vef00...@nifty.ne.jp # BTW, a good anti-virus solution is to stop using Microsoft Windows # (at least Microsoft's mailers)! :-) I suppress the preview pane for viewing the contents of my mail and use only two panes, one for mail folders and the other for the list of emails in the selected folder. To check emails, I right click on the subject line of the email, select Properties, select Details, then select Message Source. That opens up the entire email in its own separate window to include all header info and the entire message in the body. I can read the message and check addresses without ever opening up the mail. I generally don't open any attachments unless I know the person or have had the attachment checked. There's a very easy way which costs nothing to have some very complete and effective virus checking. Go to any one of the more high profile free email websites to open an account. I find they're very good at checking for virii. Also, that way if you are anywhere which has web access, you can keep up with any of your emails. And keep the personal email account back home strictly for private personal and discretionary communiqués. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: A very nice game (an example)
For those interested in how to track down something like this, take a look at the header information. You'l see a bunch of Received: xx lines. In this case there were 6 of them in the email I received. To start with the first received, go to the *bottom* one. That's where this post first entered the net but isn't necessarily the originating point of the email. To cross check this, also take a look at the From: line. I get Received: (from daemon@localhost) by ruebert.ieee.org (Switch-2.1.0/Switch-2.1.0) id g3O9LbE23259 for emc-pstc-resent; Wed, 24 Apr 2002 05:21:37 -0400 (EDT) From: jmw j...@jmwa.demon.co.uk Now, take a look at the Message-Id: line further down. I get Message-Id: 20020424215907.d25ca22...@coer.zju.edu.cn This one is little more difficult for some hackers to hide. We can see there's some discrepancies in the domain name. Notably coer.zju.edu.cn and jmwa.demon.co.uk To start tracking this down, I use several websites for searching. One is Amnesi at http://www.amnesi.com/ The other is DNS411 at http://www.dns411.com/ The Amnesi one is very powerful. Searching under coer.zju.edu.cn, we find that it crosses to the IP address 210.32.156.246 The people hosting that domain name is is Zhejiang University at Hangzhou, Zhejiang 310027, China. They cover IP addresses 210.32.128.0 to 210.32.159.255 If we apply a www in front of the coer.zju.edu.cn, we (surprise! surprise!) end up at a Chinese firm titled Centre for Optical Electromagnetic Research. or a place which uses the acronym 'COER '. We still don't know where the email came from. I would bet though that one or the other of these places would be able to track it down. It would be this point I would send off a gently worded email to webmasters, postmasters and abuse at both places. I would take the base domain name, and then at the front of it add Webmaster@domainname Postmaster@domainname abuse@domainname I assure you, one of these will be a valid address for your complaint. First, I would Reply to the email and delete the email addresses which come up in the reply. This keeps track of the email throughout all the platforms it traveled. I would not delete the subject line. Second, I would state the incidence in very brief terms at the top of my email. Webmasters have enough to do than wade through long quoted material to find the message. Keep it brief and extremely polite. Third, I would copy and paste under my message to the webmaster ALL of the header information to the email under my message. Then, finally, I would copy and paste under the header information all the information in the body of the email. I am asking all of you NOT to do this with this particular post we had. Our webmasters are perfectly capable of doing this and taking care of the business. I'm merely presenting a way each of you can in your private emails can take care of offending emails. I can testify to the fact that if you follow this procedure, it can be most effective. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Does San Diego Require NRTL Marking to Install ITE
You have been able to get Early Use Letters from UL, but I think that policy has recently changed a little. Contact your test engineer. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: U.S. Safety Regulations
John Woodgate j...@jmwa.demon.co.uk wrote: This *might* be significant in the UK, because the parliamentary draftsmen who interpret the Directives as Statutory Instruments, under the guidance of Ministers, have been accused of 'gold-plating' the Directives, i.e. 'stretching' the provisions in the direction of higher stringency. This criticism may be justified, but it may also be balanced by an official reluctance to prosecute unless advice and warnings are disregarded. But John, isn't that simply the method for all statutes? Aren't officials allowed to follow the letter of the law OR demand a stricter interpretation (within reasonable limits) rather than a weakened interpretation? Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Masking - was: chassis bonding - star washers enough?
Very good question. In my experience, the corrosion issue with regard to masked off areas has never been a factor. Yes, it will corrode, but the teeth will cut through that. The masking off of areas has also been internal to the product. Yes, I've also used the star washers on painted areas (non-conductive paint at that) without a problem, but my *preference* is masked off areas. If you're subjecting your product to some extremes in environment other than normal office environment, then corrosion will most definitely be a concern. If you're going to use star washers on surfaces painted with non-conductive paint, then you may want to consider using a torque wrench for securing the nuts or bolts during assembly. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: chassis bonding - star washers enough?
The following is strictly my own opinion regarding star washers. Others here probably have lots more experience than I. The following is also regarding bare metal-to-metal contact only. I always require masking off around the area where grounding is done. First, the only way the grounding integrity of whatever you end up doing can be checked as being sufficient is to check it with the ground current test. Second, the integrity of the ground is highly dpendent upon the torque imposed upon the the nut or screw used for securement. Get a calibrated torque tool for the job. Thirdly, I've had some very serious discussions with some NRTL test engineers regarding external toothed star washers versus internal toothed start washers. It was *require* at one time for me to use internal toothed star washers to protect the integrity of the cutting action of the teeth to chassis. It was *suggested* at another time by another engineer to use external toothed star washers so that the integrity of the teeth could be easily inspected. My personal preferences are: 1) use only metal-to-metal contact for any sort of ground, 2) if in any doubt - test it. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: LED Color
For the United States, I believe Bellcore has a spec for LED colors in 499. Green - Linked with no errors, Yellow - Linked with errors, Red - Dropped link Not sure about the standard. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Relative merits of various logic families in not generating RFI
You might find the following website from Intel useful for this question. It'll give edge rates, input and output construction, ... From there, you can make some conclusions. http://focus.ti.com/docs/logic/catalog/resources/selectionmatrix.jhtml?fileN ame=seltree_by_volt Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Temporarily disabling a fire fighting system
John Woodgate j...@jmwa.demon.co.uk wrote: You are probably not allowed to turn the system off unless the building is unoccupied except by fire-fighters and a minimum maintenance crew. Not really. All that's needed is to call the central office for the alarms telling them to put the system on Test for a certain length of time. The central office will ignore any and all alarms during that time. But past that time, they'll call the appropriate emergency crews. At least that's what's done here in the U.S. Don't know about elsewhere. Now maybe it's worth visiting that issue when writing up the user manuals. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Conductive Coatings/Conductive Plastic
Did some research into switching over from conductive coated plastics to conductive plastics. The turn off was due to the metallic additions to the plastic with conductive plastics, the molds wore out faster than plastic molds. Tooling was expensive for the product in mind, so I have no idea if that's a factor with yours. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Earthing of conductive floor tiles
They can be. It depends upon what your requirements for conductivity with the floor are. You can also use plain old bare concrete floors without any coverage. They have been known to be sufficient for some conductive requirements. Concrete flooring can be sufficient for such things as storage or not-so-strict assembly areas. But, concrete can be dependent upon the water table and/or moisture content of the ground it's on. Or, the floor can be painted with conductive paint. A paint specifically made for floors. But you may have to monitor the floor more often. Paint has a tendency to chip. Or you can have the tiled flooring bonded to building earth ground with copper strips. Or, you may not have to have the tiles connected with copper strips. Best to have a defined goal of conductivity that you're going to need, then work from there. If you need clean room or telco/Bellcore or medical equipment mfr type grounding, you might consider using the tiles because their conductivity is repeatable and reliable no matter what. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: creepage v breakdown voltage
I've done my own testing and researched the thing as well. I think we've had some serious discussions here about this subject in the past. If the archives are available, it would be beneficial to go through them. Also, get a little hipot tester from any of the hipot mfrs for your own bench testing. That's highly educational as well as nipping problems in the bud. You'll first have to jump into Paschen's Law and all that involves with pressure/humidity/geometry of the probe tips used, etc ... Basically, I start with 1Mv/meter STP and work down from there. Therefore, 1mm means 1Kv. Now, throw in a x2 safety factor and you get 2mm spacing. Now increase to 1.5Kv and you end up with 2.5mm? Well, okay. Surface contamination sets in over time? Well, okay again. Obviously, I've been doing some extreme fudging, but it ends up darn close most of the time. Follow the standards when in any doubt. I'm not really sure, but I was told many years ago that wire mfrs use as much as a x7 safety factor for their insulation or used to. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Wire spool labeling requirements
Gary, I can go along with the documentation hunt as well. And I can understand that their approval cycle would probably increase by a factor of x10 (I'm not joking) if they had to do all the research to the parts themselves. I believe that's really what's at the bottom of it all. But, it's having to put up with vendors who would burn your ear off complaining that the NRTL is one with the approval and the records and that's what they're paying all this money to do, etc ... I've gotten to point where I'm beginning to sympathize greatly with these vendors. And, I am also very aware (from an unfortunate experience) that the website is not that reliable as in being updated as it should on a regular basis. There's lots of reasons for that. Some most definitely with the vendor. Not to detract from their or anyone else's quality of work, but I do know that as of only a couple of years ago, it was the engineers who wrote up the reports. Now, all that gets handed over to a secretary pool and that mistakes have increased as a result. I'm assuming that may also factor in to the rather strict show me state of mind over there. Something I don't think they should slack off on. After some of the things I've seen, I'm rather glad everyone gets the same scrutiny and I've gotten quite an education being involved with it. It may be a pain in the butt sometimes and there are certainly times where issues appear from left field, but I really do have a lot of respect for the engineers who have more than 3 years experience working 15 to 20 (or so) product approvals per month. All different kinds of products. The reviewers seem to be very well qualified. All very approachable and all very procedural. Which I guess it really should be. I do know that they requiring you to get the paperwork instead of them at time of submittal hits several birds with one stone - educating the submitter what's needed, verification FROM the vendor, verification OF the vendor, etc I've had the experience of handing over a copy of a live approval from the vendor but something on it was not right. For some reason, it didn't effect my product approval, but the engineer contacted the field office about it. And I was not privy as to why. they certainly do keep a very professional atmosphere as well. At least the people I've worked with directly. Yes, there are times where we throw a wrench and complain, but in the end, I can understand most of what they require. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Wire spool labeling requirements
Wire can be easily respooled and used by another wire vendor or wiring house that's not recognized. Labeled spools give a higher confidence level then labeled wire. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: ( More) Laser Safety Questions
I don't know. That's a very interesting question. For each separate title in the CFRs there's a separate federal enforcement agency. CFR Title 47 Telecommunications is the FCC. CFR Title 29 Labor (or workplace stuff) is OSHA, etc ... and thus CFR Title 21 Food and Drugs is FDA. That's what happens when new laws come into effect - they try to determine if an enforcement agency already exists. If there is none, then they have to start up a whole new agency. That's why the FCC was started (as were others) when the law was passed regarding telecommunications. So that's why CFR Title 47 is FCC country and CFR Title 21 is FDA country and the two don't mix. Keep in mind that although the laser laws are obviously written for laser safety, much of it is actually for the medical field as well as experimental scientific stuff where the potential for immediate and permanent harm is present. The OSHA requirement specifically addresses equipment being approved by an NRTL. But, with laser products and systems, you apply to the FDA. The FDA is not an NRTL. And it will never be since NRTLs are approved by OSHA. The FDA and OSHA are enforcement federal agencies in parallel with each other and don'tapprove each other's methods. And you get nothing back from the FDA except some letter acknowledging your submittal. Nothing else. There's no approval to speak of. Certainly if you misrepresent your laser product or system and some unfortunate incident were to happen, you would most likely be charged with something from the FDA itself. But not limited to the FDA. The radiological side of things are also touched on by something like 1950 which probably does borrow from the FDA. And since 1950 is used by NRTLs for product compliance, maybe that's how OSHA might also get involved. It sounds as though if you're unfortunate to have some accident befall you, you could potentially get multiple hits from several different federal agencies. I don't know Jeff. Like to hear the others about this. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Don'r Get Caught Running a Red Traffic Light!
Interesting stuff Paul. With all the crap about pirate cable boxes and things, I'm surprised someone hasn't jammed those boxes. Anyone know what the immunity standards of such devices would be if it's required? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Don'r Get Caught Running a Red Traffic Light!
Just as a side issue about remote monitoring of red-light runners ... One unintended consequence of cameras watching for people who run lights happened in Fremont about 2 years ago. A couple of stop lights were set up with cameras as an experiment. During the course of rush hour traffic one day at one of the experimental camera sites, an emergency vehicle was stuck behind several vehicles sitting for a red light. Apparently the fire truck was boxed in since the roads were several lanes wide and the truck was all the way over in a right lane. Lights and siren were blaring away. Q: Did any of the cars move out of the way of the fire truck and in doing so some would have to move through the intersection and thus thru the red light? A: No. Reason: No one wanted to get a ticket running the red light. Be rather ironic that the fire truck was responding to the home of someone sitting at that intersection. Just something to think about. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Laser Safety
Gary, agreed. It must be clearly stated. As Jon Curtis mentioned, this is a very tricky declaration but one I've done. Also, in another post, I mentioned that some agencies will challange disconnect of the receive end leaving the fiber live. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Laser Safety
Yes, Jon, thanks. Again, I was being very specific about the caveats for this declaration. Also, not only breaks with fiber, but there are some European agencies which have challanged the fact that if the fiber connection to the receiver end of the fiber is disconnected, there is a live end of the fiber capable of Class IIIb exposure. Proceed with caution. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Laser Safety
Hi Mark, I was very specific about the conditions of the declaration. Scuse me for being a lawyer, but in order to do the type of declaration I mentioned, you must clearly state that all laser ports be populated even during service or maintainance. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Laser Safety
Hi Mark, Absolutely. The thing is to do with this type of declaration to the FDA, which I've done, you have to state that any connection or disconnection of fiber cables shall be done only when the equipment is powered off AND that prior to power up for any service maintainance and/or normal use that ALL fiber connections to the laser transceivers be made. In other words, during normal use, service or maintainance, the intent of the product is to have ALL lasing be in the fiber - i.e. all laser transceiver ports are populated with fiber. All this has to be clearly stated to the end user in the documentation. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Laser Safety
Do the acid test type question ... During normal use, what are you exposing the end user to? For instance, with a laser pointer using a Class IIIb laser that emits unprotected from the pointer, the pointer is Class IIIb. If instead, you are using a Class IIIb laser for fiber optic communication and the entire beam is contained within the fiber, no lasing is emitted from the product during normal operation and/or service or maintainance, then you *could* declare the telco product as Class I. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Resistors pulse loading capabilities
Massimo, Just to underscore what others have stated, long ago in one of the resistor mfr's catalogues, there was a discussion of this topic. Essentially, do not violate the DC wattage rating of the resistor based on a 1 second time period. As an example, a 1W, 1 Ohm, carbon composition resistor should be able to handle a. 1A (or 1V potential) continuously, b. 2A (or 2V potential) at 50% duty cycle, i.e. 1/2 second duration, c. 4A at 25% duty cycle, i.e. 1/4 second duration, etc ... all the way up to the maximum voltage rating of the resistor. For a 600V rated resistor, this would mean the maximum pulse allowed would be 600V peak for less than or equal to 1/600th second or 1.6 milliseconds. This particular conclusion I have doubts about. I explain below. Fusing characteristics of wires is non-linear and therefore for large currents through a resistor (I don't know what that might be), I doubt the above. But for low currents, let's say less than 10 times the current rating of the resistor for the sake of argument (in the case above, that would mean anything less than 10 amps), I think that's acceptable. This is all spectulation and I am by no means an expert. But, if there is any question, please consult the mfr. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Creating a Reliability Department
I have been given a consulting opportunity to develop a plan for a Reliability Department for a fairly large manufacturing company of Laboratory Equipment. Since my background is in compliance I could use some advice on how to get started. 1. The goal is to hire one permanent employee and grow over time. What are some justifications/success stories/strategies for having a Reliability Department? Any part or device that's mission critical (for lack of a better phrase) needs reliability. There are wide range of functions that reliability engineers perform, so it's necessary to define exactly what it is this reliability person will be doing. Someone in aeronautical reliability will have a vastly different job function than say someone in an integrated circuit mfr-ing environment. Someone who's a reliability engineer could have their whole career in the hard-drive industry and yet some other reliability engineer could have their whole career in the automotive industry. 2. Assuming the goal is to have the best reliability department in the world, how do we get started? Define exactly what it is that is required of these people. In other words, if all the customer requires are calculated MTBFs, that's easy. Internally, the reliability engineer should be constantly comparing calculated failure rates with actual demonstrated failure rates from the field. From either the calculated failures or the actual demonstrated failures, the reliability engineer is the one to *advise* how often things will perform for the given requirement and how often things should be inspected, replaced, or maintained. It can be a huge job, or it can be made very simple. What are the stages which should be followed for developing a Reliability Group? What would staffing requirements look like for each phase? First, a widely experienced person to define what it is required of the Reliability department, what inputs will be used and/or monitored, what tools and standards are needed to be used or followed, how the data is to be massaged, and to whom the results are to be presented. Then the staffing moves into (depending upon what this company is and how big) people who are able to do failure calculations, glean out demonstrated failures in the field from Customer Service, and who can do testing in a lab. 3. The goal is to have this position report to Manufacturing Engineering. From a compliance standpoint, this would be a conflict of interest. Does the same hold true for Reliability Engineering? Yes. Ultimately, reliability should be part of say Quality. And Quality should be a department seperate from engineering and mfr-ing. Some here may shudder at the thought but that's just my opinion. 4. This department may include a global function. What is the best method to integrate this department globally? Refine the way customer service reports and returns from the field are done. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: Chamber Doors
There's a cam of some sort when actuating the door to open or close. That has broken only once in past. Chamber has been here for several years. The teeth didn't shear, the entire cam broke in half. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: TUV NRTL
It's been my understanding that the various branches of TUV reside and oversee product safety in specific regions within Germany. And that being in a sense franchises, they compete directly with each other outside of Germany. It's also been my understanding that in a similar way though more subtle, the various branches of UL within the US also compete with each other. In other words, even though the Santa Clara facility is conviently right down the road from me, I could send product off to Melville. Any profits made by Melville aren't really benefited by Santa Clara. The difference between TUV and UL is that in some cases, and I'm going out on a limb, TUV Rheinland might not accept results from TUV Product Services although that would have to be some extreme case IMO. UL branches on the other hand accept each others results. Corrections anyone? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
Re: broadband RE from AC induction motors
The need for snubbers on the relays? I dealt with a product which used a 1 1/2 HP motor with arcing visible to the operator and did have any high end emissions. 600 MHz is rather high for a motor. Even 30 MHz. Would have thought problems showing up in the conducted side of things instead. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Spray-on Conductive Coatings
Darrell Locke wrote: Dear Colleages, We have seen an issue lately with spray-on conductive coatings used on the inside of electronic enclosures. The coating works great for EMC, but there seems to be a problem with adhesion and tiny flakes of conductive material getting in the electronics. I'm thinking that the spray-on type materials should not be used at all. Has anyone else experienced this problem? Try to avoid it if you can. You're absolutely right about the problem of flaking onto or getting into any energized electrical parts. Safety will be all over you about using it. And because of that, you'll have to get: 1. a UL approval for plastic of the cover, 2. a UL approval for the plastic molder who's making the cover for you, 3. a UL approval for the conductive coating, 4. a UL approval for the marriage of the coating with the plastic, 5. and a UL approval for the vendor applying the coating to the cover. All approvals have to be verified of course in black-and-white for approval and for all subsequent factory inspections with of course appropriate Certificates of Compliance handy as well. As far as emi, it's sort of a once used thing. Don't use it on a cover that will be repeatedly removed and replaced. It's not meant to be disturbed to any extent once in place. And do not use it as a primary ground either. And it's all dependent upon the thickness of the layers for effectiveness. Oil based coatings seem to have a higher ohms-per-square than the water based coatings. You want to keep it down around less than 0.5 ohms. Been there, done that, sorta don't want to do it again. Other personal experience mileages may vary of course. All strictly my own 2 cents worth of opinion. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Switch Inrush Ratings
Duncan, You might want to get all the info you can get on contact ratings for mechanical relays and contactors. Then, use that information by analogy. DC operation of a switch is the more destructive by orders of magnitude than AC operation. Since the normal cycle of AC will quench any spark within 16ms/20ms, DC on the other hand provides no quenching of the spark till the contacts make. That's why you will see great differences between the AC and DC ratings of switches (the great switch mystery finally demystified). Any power ratings for switches are typically done in horsepower. Inrush, careful - I'm assuming here, might be estimated from some fudge combination of voltage and current over time. The relay people have gone through some intensive research over the years regarding MAKE/BREAK conditions, the success of various platings for the contacts, and snubber design to help with the reduction of the spark intensity (i.e. inrush problems). Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Comparing EMI test results
Not to rain on the parade, but be careful when comparing semi-anechoic chambers versus OATS that are of different distances, i.e. 3m vs. 10m. You may get not only widely different measurements even when compensating for the distances, but you may also obtain different frequencies. On two occasions, I've had frequencies show up rather prominently in the chamber prescan not to be seen to any significance at an OATS. In other words, to get a fairly reliable comparison between a chamber and a site, in my opinion, you'll first have to compare a 10m chamber with a 10m OATS. Then, work backwards to a 3m chamber. You will also have to develop a fudge factor for the size of the EUT. The size can effect results as well. You may get good correlation with a small tabletop EUT and terrible correlation to a much larger device. Possible reasons for this I'll leave to discussion. But suffice it to say, the closer the product is to a point source the better the correlation. The farther the product is from a point source, the worse the correlation. At least in my experience. Name the site with which you will be getting an official measurement as your standard, then work all the others in reference to it. The standard site will be the one which will have the final say. Sorta been there ... Done that ... etc ... Sorta gave up. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Primary Power Range on a Product Label ...
I've never had an NRTL actually tell me what the specific domestic voltage *should* be. Either one is okay. I'm fairly certain you could get by with 100-115 as well. You probably know already, but keep in mind the primary voltage range placed on the label of a product directly sets the upper (+6%) and lower (-10%) limits of HI/LO line testing at an NRTL. 100-120V yields 90 and 132 100-127V yields 90 and 135 A difference of 3 volts on the upper side might not matter. Then again, it might. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Cortland Richmond wrote: AIrbag testing? Well, since it costs about $US 1500 to replace them (here), I suppose there WOULD be a price hike! A couple of kids were caught by the police in a parking lot. Seems the fun thing to do to people's cars was to walk around the parking lot with baseball bats and bang on the front bumper causing the air bags to activate. Can't imagine what that all cost. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
RE: EMC-related safety issuesKyle Ehler wrote: Another point of trivia is that a fresh oil change and new air filter prior to having your vehicle smog tested will improve the emissions results. At one time there was available OTC a fuel additive that one could deploy to further skew the results in your favor. I knew a guy who drilled a small hole in the side of his carborator, attatched a hose setup that you would use for an acquirium the other end of which was put into a water bottle. While the car was in idle, he'd adjust a valve on the hose to a slow drip of water into the carborator. This setup was on an old truck of his and he always got terrifically low emissions readings. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Warranted parts for a car is a whole other discussion. Warranties are simply for as long as the mfr/dealer want to do the contract. I'm not sure if there's a law concerning minimum time of warranty or if it's simply driven by the free market. Supplying a parts inventory by the car mfr is I think is required for a maximum of up to 10 years. The contract for making that part is then picked up by some other shop who thinks they can turn a profit. I can't imagine Moter Vehicles passing a car for inspection with a big gaping hole in the dash or steering column where the air bag used to be. But I'll be the first to admit that I don't know any of the laws requiring parts such as selt belts and air bags being replaced years down the road. I did have an experience back in the early 80's in trying to replace a faulty seatbelt with a used one and I was prohibited from doing that. I had to buy a new one. That was back in CT so that may have been a state thing. I can only think of at least one or two modes of transportation that are covered by federal law for replacement parts being available for the entire life of the thing for as long as that may be - jet airliners and trains. Elevators and escalators also come to mind as well. Anyone here work at Otis? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Point taken Ken, but consider signal lights. They're essentially safety devices and they're supposed to be maintained on cars which have been transferred amongst several owners and are decades old. Same idea with windshields, I guess also. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Re: Electric Shock and Water
If your colleage doesn't understand why you shouldn't mix water and electricity in general, just tell him that water has a tendency to be rather unpredictable and can go anywhere. Someone likened it to a three dimensional resistor and that's an excellent example. Add to it a very deformable 3D resistor. And since electricity likes to follow water, electricity will also end up going anywhere. Other than that, I agree it's a pretty naive question. I picture the guy in bare feet on the metal ladder in water with drill in hand asking, so what's the matter? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Ken Javor wrote: Curiosity. How long must airbags work? As long as you have the car, supposedly. Same with seat belts. They're all safety features. Interestingly, if you have a cracked or broken windshield, a cop *can* write you up for the car being unsafe. I've never heard of it, but a classmate of mine who became a statie told me when he saw a huge crack in my windshield. I'm also under the impression that manufacturers are responsible for maintaining a repair/replacement parts inventory to dealers for only 10 years. Not sure about that one. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Rich Nute wrote: EMC? Ha! You raise a good point since the FCC legally can but hasn't implemented an American version of immunity standards. The words must accept on the FCC labels of your effected devices are evident of it. Maybe some day we will have do immunity testing. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Let's be real careful here and give credit where credit is due. The Pinto incident was in many ways not a safety issue with regard to safety testing and the safety engineers at Ford. The Ford Pinto fiasco was clearly a management issue. Tests were done to the 20 mph rear impact standard early in the Pinto development. Those tests clearly showed that the Pinto failed. Those tests were performed by Ford's safety team according to National Standards and were the results were reported to management. It was management who decided to go ahead with the failed design. The Pinto incident shows that we as safety engineers can really a take a horse to water but making it drink is a wholly different issue. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMC-related safety issues
Personally, I could list a ton of stuff that would instill fear and loathing amongst the fainest of EMC hearts. Sitting in a jet airliner at the end of the runway readying for take-off and watching the cabin lights dim slightly in sync with the sweep of the main radar dish just a couple of hundred yards away. ESD events in the kitchen area of the airliner causing the phone in the cockpit at the other end of the plane to ring making the pilot pickup to answer. ESD events in the control tower of an airport causing the computer and other essential equipment to crash. Enough spurious radiation events to require laptops and cell phones to be turned off upon takeoff or landing. Why? Am I and hundreds of others trusting out lives on something so ... sensitve? But we think nothing of dialing up the cell phone inside a car packed with digital controls for things like the brakes, the accelerator, gas control ... The automobile industry does its best to test for the severest of electrical events with lightning simulations. But what about internal to the car less than a meter away? And by the way, do they allow cell phones and laptops in that airport control tower? Do they have conductive floors and require people to wear ESD proof shoes? Define safety related issues? Does it necessarily have to do with physical safety? How about the spurious radiations from an ATM being decoded by someone nearby to gain access to your bank account to drain it? Sorry. Must be the Day After New Year's Day effect ... - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMI guard bands
John Woodgate wrote: I would be suspicious of that; it is a 'near-field' scenario, which means that the emission field strengths are complex and impossible to calculate. The Class B limits are related to a 10 m separation of source and potential victim, and that implies far-field conditions for emissions above about 5 MHz. That's true, but weren't the early measurements for Class B done at 3 meters? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMI guard bands
Thanks to all who responded. Yes, Ralph Showers. I kept the response from him for the longest time. But, after several program and hard drive crashes, it's lost. Thanks again. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMI guard bands
Historical bit of news ... I asked a similar question a couple of years ago here and was referred to a gentleman who was in the writing of the original FCC limits. Can't remember the man's name but he's a professor at Univ. Penn. if I remember correctly. Anywho, the answer I got back from him was that the limits were empirically derived in reference to interfering with television signals. So, the worst case (which turned out to be Class B) was a tv back to back across a wall from another device in an apartment complex. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: EMI guard bands
Tania Grant wrote: Amund, My minimum criteria and recommendation has always been at least 6dB. However, how many engineering managers, upon finding a 1.5 dB margin in their favor, rule ship it! nod Although in some markets, there are customers who require -6dB under the Class A limit. Although if I had it my way, I'd make it about -10dB under the limit. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Sometimes product safety just isn't enough
robertj wrote: Ever since I saw this, I have been wondering what's going on in the mind of this guy: - doesn't have a clue - can probably get away with this - my tools are in good shape, everything's OK Well, he is working next to a wet bar. Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Thermal effects on EMC and Earth Leakage
How much of a temperature increase are we talking about, how much do emissions increase, and what frequency(s) increase in emissions? - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Sometimes product safety just isn't enough
I think it's worth mentioning interpretations of the definition of end user in 950. In my opinion, end users are obviously people who use the equipment and are also not expected to be aware of the hazards. That's why, in my opinion, the thread about safety critical parts was so difficult to pin down. We as safety engineers know some rather obvious hazards which could occur during design, assembly, and use. But, in selling to the general consumer market, the product is being put in the hands of maybe uneducated or non-technical people of a variety of ages. As such, you have to anticipate little to no experience or knowledge. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Regulatory General Discussion : ouput of Compliance group
Andre, Pierre-Marie wrote: So has anybody some thoughts or argument on the measurement or evaluation of an Compliance Group ? Well, I'd hate to let the dirty little secret out of the bag for those of us who would fall under such and evaluation. Important in such an evaluation would be that the company has allowed the compliance engineer to have significant input to the design/mfring processes. I've been in companies where evaluations from the compliance engineer amounted to nothing more than a suggestion. Very frustrating. Other places had the compliance engineer greatly involved as a signatory in product release and with ECR/ECOs. Start with an ideal world where the compliance engineer has complete planning, budgeting, signatory/approval powers with the complete product cycle from prototype-to-product release-to product obsolescence. Consider that as the complete model. Then, as the person has less and less involvement/approval power in those areas, they are thus less responsible for them and thus, they are not to be evaluated in those areas. You'll probably find the typical compliance engineer ends up in reality scheduling tests w/no approval powers, has input to ECR/ECOs but no signatory powers, inputs into product design by way of memos, sometimes are the last to know about significant design changes, and might answer to someone who knows little about compliance engineering. IMO, evaluation would be difficult. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Sometimes product safety just isn't enough
I've dropped the picture into a Word document and titled it, You Can Design Only So Much Common Sense Into A Product. Then at the bottom, put Hand drill = $35 Metal ladder = $50 Bare feet on metal ladder in pool ... Priceless and posted it outside my cubicle. It's been quite a hit ... Thanks. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Quantifying EMC
Ken, Personal experience with a specific circuit for a specific application, migrating from a 2-layer board to a 4-layer board resulted in something like a -10 to -15dB reduction in emissions. That was probably the most dramatic reduction in emissions with regard to migrating the same circuit from one layer count to another. The following is an extremely rough estimate ... Board cost is almost directly proportional to layer count. So, as a *very rough* rule of thumb, use the ratio (new layer count)/(old layer count) So roughly speaking, migrating to a 4-layer board from a 2-layer board should cost 4/2 of a 2-layer board or 200% increase. Migrating from a 4-layer board to a 6-layer board by adding 2 layers would result in the 6-layer board being 6/4 or a 50% increase. IOW, more layers has a mitigating effect with additional layers. If you remove layers, the ratio works the other way. Removing 2 layers from an 8-layer board will result in you paying 6/8 the cost of the 8-layer board or 75% the cost of the 8-layer or a 25% reduction. The trick with this ratio is dealing with 2 layers at a time. In order to keep the board constrution symmetrical, you can only deal with even numbered layers, as you probably already well know. So, increases or decreases can only be estimated multiples of 2. One thing follows from this. Suppose you were given the magic wand to set any layer count you wanted in the beginning. BUT, afterward you're only allowed a 20% increase in cost for modifications, You must start with 10 layers anticipating an increase to 12-layers resulting in roughly a (12/10) = 20% increase in cost. I think this is something that's missed in most prototyping considerations. As far as management is concerned, IMHO, the decision should be to maximize layer count as soon as possible. This has these effects in my opinion: 1) it's far better to overkill for EMI on first spin prototypes, 2) removing layers has more of an appeal budgetwise than adding, 3) overkill leaves available real estate for any future mods which are usually bound to happen. The whole, point in my opinion, is to set up a simple board construction (layer and stackup) that will survive as long as possible even through all sorts of modifications. Therefore, board costing can be anticipated and stabilized as best as possible for a long time into the life of the project. Undercounting layers which might result in adding layers later in the process can have a much more disastorous effect especially with large quantities of boards are in play; time-to-market cost, ECR/ECO cycle cost, design cycle cost, MRB/scrapping material cost, added burden on budget, ... etc ... I certainly understand all too well we in business don't live in a perfect world. But, given the chance to incorporate some of the ideas that I consider important, it's far better to overkill for EMI/EMC right off the bat than having to scramble around a week or so before final product release. The above all strictly my opinion ... Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: physics behind EMI powerline filter
Basically it depends upon the energy being reflected back to the power supply and/or absorbed by the filter. In either case, it dissipates into heat. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: 80/80 Rule
I beg to disagree. The Binomial Distribution is done with replacement. The 80/80 rule is supposed to be done without replacement. Therefore, the only discrete distribution which satisfies the question - What is the probability that M samples of a sample population S will pass/fail when S is taken from a total population N with an expected pass/fail rate of P/F? without replacement is the HyperGeometric Distribution. In other words, the HyperGeometric Distribution answers the question - if your company makes a total of 100 products per month and you expect 20 of them to fail, what's the probability that 2 samples of a random sample of 10 being tested without replacement each month will also fail? The HyperGeometric Distribution says in such a scenerio that the chances 2 samples will fail are 31.8%. Also, the probability that 3 samples in the above given conditions will fail is 20.9%. Which makes for some odd interpretations. But in any event, even though you think you're working with an 80% success rate, you have only a 70% confidence level. Now, I'm certainly no statistical expert, but I believe the Binomial and Hypergeometric distributions become nearly equal in results only with large numbers. You can play around with this on Excel since the various distributions are built-in spreadsheet functions. - Doug --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Decisions/Choices
Let's keep a perspective here. Whether you wish to accept it or not, we are all members of this list because we agree to the terms of being a member of this list. The administrators can be as dragonian or libertarian as they wish. Thankfully they aren't on both accounts. I think they do a good job as administrators and I think John did a good job as a member. But things happen. I don't know nor do I want to know what happened off-line. But, as far as I'm concerned, John made the decision to leave and left of his own accord. He was not tossed off the list. So with all due respect, email John offline and ask him to come back if you wish. If he does, he does. If he doesn't, then he doesn't. And that's that. But, let's move onto something else, please. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: 80/80 rule for euro compliance?
I have never liked the 80-80 Rule as liberal as some may think it is. I've even toyed with the idea of writing a paper about it, but I think I'd go to sleep writing it, let alone presenting it. If you take the basic premise statistically and work out the numbers yourself, you will surprised at the results. Say you have a given a total population of 100 products. In that total population, you expect 20 products to fail. Now, you take 5 samples from that population and calculate the probability of failure. The chances of 1 product failing in the 5 samples drawn is 42%. The probability of 2 products failing from 5 samples in the above example is 21%. IOW, you have a 1 in 5 chance of failing the 80-80 Rule by following it. That's bad. And if your company is into the practice of shipping relatively small amounts of product, that can be bad also. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Define Continuous DC Voltage
John, I read that, but I still see how it has anything to do specifically with the word hazardous. It appears that part of the standard in the poster's question is simply the only place in the standard where continuous is used in conjunction with DC voltage. I'm sure we could dissect this to no end. Perhaps the word continuous is used in the standard to reinforce the idea of uninterrupted. In other words, if we define a discontinuous DC voltage as being switched to zero or through zero (for example from a positive potential to a negative potential, then a continuous DC voltage is simply one that is not. - Doug --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Define Continuous DC Voltage
Well, to follow John's and Tania's comments ... For John, there wasn't any mention of hazardous in the original question. Only what would qualify as continuous DC. So, IMO, it doesn't matter what the frequency is as I stated with regards to an rms nor the level with regard to hazardous. The rms converts any signal dc or ac to a continuously delivered power to a load in terms of real power. Which brings me to Tania's question as in, whatever level you wish to consider. If it is 1/50th, then so be it. I thought it was an interesting question when I started considering heating effects with say fine pitch traces and such. Anywho, just my two cents ... Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Define Continuous DC Voltage
eric.lif...@ni.com wrote: So friends, how continuous must DC be to qualify as continuous DC? Personally, I'd say when the source can deliver some sufficient level of real power (rms level of power). That is basically the definition of rms anyway. To make the point with two ridiculous examples, (1) if by shorting a 5 volt digital signal to ground you measure 1/100th amps of rms current, then I wouldn't call it DC. (2) if by shorting a 5 volt digital signal to ground you measure 10 amps or rms current, then I'd most definitely call it DC. But that's just me and my 2 cents worth. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Definitions - Safety Critical, Safety Circuit
Couldn't we just go to the front of the UL1950/60950 standard and agree that a safety critical part or device or circuit or construction is simply something used ... to prevent injury or damage due to: - Electric shock hazard - Energy hazards - Fire hazard - Mechanical hazard - Heat hazard - Radiation hazard - Chemical hazard Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Safety Critical etc - the future
John Woodgate j...@jmwa.demon.co.uk If you are referring to my post, I plan to report that there is discussion here on the subject, and recount some of the points made. What we need is a very-widely accepted standard definition. Thank you, John. We are here but to serve ... grin - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Safety Critical etc - the future
John, Extremely valid question since we are it seems in the process of moving toward the world-wide concept of 'one test, one approval'. I would be very surprised if this very question has not been addresssed. Regards, Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
Re: Definition for Safety Critical Component
Definition for Safety Critical ComponentI'll add to Richard's definition by saying a Safety Critical Component is a component necessary for the safety approval of the product. It's a component that prevents a person (end user or service person) from being exposed to a hazardous condition either during normal operation or from a fault. - Doug McKean --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Michael Garretson:pstc_ad...@garretson.org Dave Healddavehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: No longer online until our new server is brought online and the old messages are imported into the new server.
