RE: Fw: working voltage measurement
Just to add to what Rich has stated - the CMRR will also vary with frequency for both passive and active systems. These variation are caused by small differences in the LCR coupling of the probes and the finite bandwidth of any amplifier. I remember using a very high gain product (A Thermal Imager - the noise figure was down around (800pV/Hz^0.5)and the end of runway radar bursts of RF were demodulated by the combined non-linearities and finite CMRR to wipe-out the IR image. I think this story might also be relevant to the debate about spurious emission in safety applications - although I believe that 'proper' safety circuits will be designed so that a single fault (such as a junction s/c or capacitor o/c)will not affect system safety. Best regards and Happy New Year Gregg -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Rich Nute Sent: Monday, December 31, 2001 1:46 PM To: Cortland Richmond Cc: xin...@cesi.ac.cn; emc-p...@majordomo.ieee.org Subject: Re: Fw: working voltage measurement Hi Cortland: One can also use a pair of probes known to be well balanced and take the difference between the A and B channels, or use a differential input accessory or plugin. There is then no possibility of high-voltage on the instrument chassis. Balance is really Common-Mode-Rejection-Ratio, CMRR. There are two schemes for difference measurements. One is measuring the high and low signals independently (through Channel A and Channel B), and then subtracting the two (A and B) signals. This requires both channels to have exactly the same gain (and phase shift) throughout the frequency range of interest. A 1% gain difference yields a 100:1 CMRR, which is quite poor -- almost useless. Another scheme is the difference amplifier, where the high and low signals are applied to the + and - inputs of the same amplifier. A good difference amplifier is capable of 100,000:1 CMRR at low frequencies. The CMRR of a difference amplifier falls off as the frequency increases. A difference amplifier may not have sufficient bandwidth to accurately measure the high frequencies in a SMPS. I have found the portable, battery-operated scope to be the most accurate and easy way of measuring waveforms within a SMPS. Best wishes for the New Year, Rich --- 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. --- 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: Fw: working voltage measurement
Yes, it's important to recognize the limitations of a test method before relying on it. In this case, the A-B method was used at power frequency and below, to observe discharge time for UL testing. The MAIN advantage was not balance so much as that the chassis was isolated from the potential being measured by the impedance of its input amplifiers. This is an additional safety measure not provided by battery operation. The _previous_ method used had been to remove the safety grounding terminal (pull the third pin) and float the whole 'scope at line voltage. The possibility of a mistake hooking things up made operators uneasy. An expedient to make channel gain difference less of a problem is to measure the point under test with both channels at once, in A-B mode, and as high a gain setting as possible without clipping in the input stage, then adjust their relative gains so that the offset on the screen is within a tolerable amount. This is often adequate for troubleshooting or specific tests. Cortland My thoughts alone are what I write Not my employers', on this night; I wish list members gathered here A happy, prosperous, New Year! --- 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.
Fw: question on emc and networks
I offered to forward this to the emc group for help. Please answer directly. - Robert - Robert A. Macy, PEm...@california.com 408 286 3985 fx 408 297 9121 AJM International Electronics Consultants 619 North First St, San Jose, CA 95112 -Original Message- From: Dieguito diegu...@gmx.net List-Post: emc-pstc@listserv.ieee.org Date: Saturday, December 29, 2001 8:04 AM Subject: question on emc and networks Hi there, I've got this assignment to make for school and I realy don't know where to begin: I have to find what standards a network has to be compliant with, concerning emc levels. So is there anyone who knows what stardards I need and where I can find them, because on iso.org, they ask a lot of money (if just for a silly assignment). And is there someone who knows where to find emc specs on networkcables, hubs, etc.? All concerning emc of course. Or does someone knows a better newsgroup to ask for this? (please let me also know the server, I'm now on pandora (belgium)). Thanks a lot and a happy newyear to all. Dieguito --- 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
In a court of law one must swear to tell the truth, the whole truth, and nothing but the truth. What you stated below is merely part of the truth. The rest of the truth is that spurious emissions emitted by unintentional radiators (the kinds of emissions controlled by CISPR 22 and Title 47, part 15B of the US Code of Federal Regulations) are at such low levels that there is no ability to cause an adverse reaction to anything except a radio receiver. It is only the field intensities associated with intentional rf transmissions that are capable of stimulating electronics operating at higher levels than radio receivers. -- From: cherryclo...@aol.com To: ken.ja...@emccompliance.com, emc-p...@majordomo.ieee.org Subject: Re: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date: Mon, Dec 31, 2001, 12:45 PM Dear Ken Any electromagnetic emissions, whether conducted or radiated, including spurious emissions (however you wish to define the word 'spurious') can be demodulated by the non-linear processes in semiconductors, vacuum tubes, and the like. So the spread of possible problems goes beyond merely preventing the reception of radio communications. I didn't catch the previous correspondence on this issue, but it seems to me that a very narrow definition of the word 'intrinsic' is being used - and this could be misconstrued by some engineers (or their managers) who are more semantically challenged and possibly lead to possible safety hazards for the users of their products or systems, or third parties. Regards, Keith Armstrong www.cherryclough.com In a message dated 31/12/01 15:46:21 GMT Standard Time, ken.ja...@emccompliance.com writes: Subj:Re: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date:31/12/01 15:46:21 GMT Standard Time From:ken.ja...@emccompliance.com (Ken Javor) Sender:owner-emc-p...@majordomo.ieee.org Reply-to: ken.ja...@emccompliance.com mailto:ken.ja...@emccompliance.com (Ken Javor) To:cherryclo...@aol.com, emc-p...@majordomo.ieee.org All of this message is very interesting and I have no problem with it at all. That doesn't change the fact that, as I and others stated earlier, there is no intrinsic safety issue with a spurious emission. Spurious emissions only affect the ability to receive a radio signal. That was and is the only issue. The fact that sometimes reception of that radio signal is safety-critical is another matter entirely. -- From: cherryclo...@aol.com To: emc-p...@majordomo.ieee.org Subject: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date: Mon, Dec 31, 2001, 7:12 AM Dear all There was a discussion about electromagnetic emissions and safety issues a couple of weeks ago which I only caught the tail end of, so I hope my comments below are relevant and useful. I would also like to make a plea for assistance. Spurious emissions and safety. Even if we ignore 'leakages' from intentional transmitters and industrial RF processing equipment (such as dielectric heaters) and also ignore biological (human health) hazards, it is quite clear that spurious emissions can increase the risks of some safety hazards. I have worked on problems where spurious emissions from microprocessor-based systems were interfering with safety-related radio communications, and also on a pulsed-laser welder that interfered with helicopter air traffic control radio communications. The laser could only be operated when the nearby airport was closed to helicopters during the night. Section 7 of the 'core' of the IEE's professional guidance document on 'EMC and Functional Safety' includes an example of a airplane passenger's laptop significantly affecting the pilot's compass reading. You can download this useful guide for free from www.iee.org.uk/Policy/Areas/Electro (note: this URL may be case sensitive). Another useful source of interference anecdotes is the Banana Skins column in the EMC and Compliance Journal, which may be read at www.compliance-club.com. The two most recent issues are 'live' on the site and the others can be read by searching its archives. The IEE's Guide on EMC and Functional Safety. This guide adopts much the same approach to dealing with EMC-related safety issues as IEC/TS 61000-1-2:2001 Electromagnetic Compatibility (EMC) - Part1-2: General - Methodology for the achievement of the functional safety of electrical and electronic equipment with regard to electromagnetic phenomena. (A key member of the IEC 61000-1-2 committee is a very senior safety expert and also a key member of the IEE Working Group that created this guide - helping to ensure compatibility between the two documents.) I understand that - after any modifications found necessary during its trial period - IEC/TS 61000-1-2 will probably become harmonised under the Low Voltage and Machinery safety directives. The IEE's guide on EMC and Functional Safety has been published for 18 months and downloaded by many thousands of
Re: EMC-related safety issues
I read in !emc-pstc that cherryclo...@aol.com wrote (in 17c.18c06c2.296 20...@aol.com) about 'EMC-related safety issues', on Mon, 31 Dec 2001: Quite a number of EMC and Safety experts took part in creating the IEE's Guide on EMC and Functional Safety, including a lawyer who specialises in high-tech issues. You will find their names listed at the end of the 'core' of the guide (downloadable from www.iee.org.uk/Policy/Areas/Electro). Many of these experts also involved their colleagues and others so we got a very wide spread of opinion. My comments referred to the IEC work, specifically verbal reports from people involved. You will have noticed that the work culminated in a TS, not a standard as originally envisaged. That in itself may be an indication of certain difficulties in its passage through IEC. I think that a passionate defence of the IEE document (which I have not studied, so will not comment on) *may* also be an indication that there is more emotion surrounding this subject than is desirable. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. --- 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: Fw: working voltage measurement
Hi Cortland: One can also use a pair of probes known to be well balanced and take the difference between the A and B channels, or use a differential input accessory or plugin. There is then no possibility of high-voltage on the instrument chassis. Balance is really Common-Mode-Rejection-Ratio, CMRR. There are two schemes for difference measurements. One is measuring the high and low signals independently (through Channel A and Channel B), and then subtracting the two (A and B) signals. This requires both channels to have exactly the same gain (and phase shift) throughout the frequency range of interest. A 1% gain difference yields a 100:1 CMRR, which is quite poor -- almost useless. Another scheme is the difference amplifier, where the high and low signals are applied to the + and - inputs of the same amplifier. A good difference amplifier is capable of 100,000:1 CMRR at low frequencies. The CMRR of a difference amplifier falls off as the frequency increases. A difference amplifier may not have sufficient bandwidth to accurately measure the high frequencies in a SMPS. I have found the portable, battery-operated scope to be the most accurate and easy way of measuring waveforms within a SMPS. Best wishes for the New Year, Rich --- 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
Dear John Quite a number of EMC and Safety experts took part in creating the IEE's Guide on EMC and Functional Safety, including a lawyer who specialises in high-tech issues. You will find their names listed at the end of the 'core' of the guide (downloadable from www.iee.org.uk/Policy/Areas/Electro). Many of these experts also involved their colleagues and others so we got a very wide spread of opinion. The IEE's Safety-Critical Systems Committee also reviewed the draft Guide and very useful input was received from its chairman, Professor Andy McGettrick. Before the IEE would publish this Guide they sent it for comment to five UK experts who had not been involved in its creation. I am pleased to say that there were no significant dissensions among the WG members or their colleagues during the 18 months it took to create the guide, or any significant dissensions from any of the reviewers. So I am surprised that you are claiming that there are problems with this IEE guide. I would appreciate it if you would spell them out to me so we can discuss them in detail - instead of just making vague statements to the emc-pstc that tend to discredit a lot of hard work put in by a number of people. If you don't wish to engage in a constructive and detailed debate - maybe you could let me know who these other experts are so I can ask them what their problems seem to be. I repeat that neither the IEE or anyone in the IEE's WG (as far as I know) has had anything other than good feedback on this Guide. While chairing the WG that created this Guide I tried to ensure that it reflected good engineering practices, and I hope to improve it still further to that end. So your detailed input is welcomed. If there is something wrong with it, I want to know what it is so I can put it right. Constructive comments are always welcomed. Keith Armstrong www.cherryclough.com In a message dated 31/12/01 16:23:13 GMT Standard Time, j...@jmwa.demon.co.uk writes: Subj:Re: EMC-related safety issues Date:31/12/01 16:23:13 GMT Standard Time From:j...@jmwa.demon.co.uk (John Woodgate) Sender:owner-emc-p...@majordomo.ieee.org Reply-to: A HREF=mailto:j...@jmwa.demon.co.uk;j...@jmwa.demon.co.uk/A (John Woodgate) To:emc-p...@majordomo.ieee.org I read in !emc-pstc that cherryclo...@aol.com wrote (in 123.96b6ec6.296 1b...@aol.com) about 'EMC-related safety issues', on Mon, 31 Dec 2001: (A key member of the IEC 61000-1-2 committee is a very senior safety expert and also a key member of the IEE Working Group that created this guide - helping to ensure compatibility between the two documents.) This very senior safety expert holds strong views that are not by any means shared by all of his colleagues, especially internationally. These strong views have, it is said, 'coloured' both the IEC TS and the IEE document. In the future work of the IEC, it is to be hoped that other equally senior experts will participate, so that a real international consensus is established BEFORE any standard is adopted unilaterally in Europe, either de facto or de jure. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk
Re: Fw: working voltage measurement
Hi Xing Weibing: 2. supply the SMPS from an isolating transformer where both supply conductors are isolated from ground. 3. connect secondary's ground and primary 's ground (neutral and ground are connected together) This is the correct connection for measuring the primary-to-secondary voltage. What I mean originally is what waveform of primary and secondary for SMPS should be : Switching waveform , sin waveform moduated by high-frenquency switching waveform or other . The correct SMPS waveform between primary and ground (i.e., grounded secondary) is a switching waveform superimposed on a (mains-frequency) sine wave. Best wishes for the New Year, Rich --- 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
All of this message is very interesting and I have no problem with it at all. That doesn't change the fact that, as I and others stated earlier, there is no intrinsic safety issue with a spurious emission. Spurious emissions only affect the ability to receive a radio signal. That was and is the only issue. The fact that sometimes reception of that radio signal is safety-critical is another matter entirely. -- From: cherryclo...@aol.com To: emc-p...@majordomo.ieee.org Subject: EMC-related safety issues List-Post: emc-pstc@listserv.ieee.org Date: Mon, Dec 31, 2001, 7:12 AM Dear all There was a discussion about electromagnetic emissions and safety issues a couple of weeks ago which I only caught the tail end of, so I hope my comments below are relevant and useful. I would also like to make a plea for assistance. Spurious emissions and safety. Even if we ignore 'leakages' from intentional transmitters and industrial RF processing equipment (such as dielectric heaters) and also ignore biological (human health) hazards, it is quite clear that spurious emissions can increase the risks of some safety hazards. I have worked on problems where spurious emissions from microprocessor-based systems were interfering with safety-related radio communications, and also on a pulsed-laser welder that interfered with helicopter air traffic control radio communications. The laser could only be operated when the nearby airport was closed to helicopters during the night. Section 7 of the 'core' of the IEE's professional guidance document on 'EMC and Functional Safety' includes an example of a airplane passenger's laptop significantly affecting the pilot's compass reading. You can download this useful guide for free from www.iee.org.uk/Policy/Areas/Electro (note: this URL may be case sensitive). Another useful source of interference anecdotes is the Banana Skins column in the EMC and Compliance Journal, which may be read at www.compliance-club.com. The two most recent issues are 'live' on the site and the others can be read by searching its archives. The IEE's Guide on EMC and Functional Safety. This guide adopts much the same approach to dealing with EMC-related safety issues as IEC/TS 61000-1-2:2001 Electromagnetic Compatibility (EMC) - Part1-2: General - Methodology for the achievement of the functional safety of electrical and electronic equipment with regard to electromagnetic phenomena. (A key member of the IEC 61000-1-2 committee is a very senior safety expert and also a key member of the IEE Working Group that created this guide - helping to ensure compatibility between the two documents.) I understand that - after any modifications found necessary during its trial period - IEC/TS 61000-1-2 will probably become harmonised under the Low Voltage and Machinery safety directives. The IEE's guide on EMC and Functional Safety has been published for 18 months and downloaded by many thousands of professionals. I chaired a well-attended one-day seminar on it in London UK in February 2001 and presented a well-attended paper on it at the IEEE EMC International EMC Symposium in Montreal Canada last August (pages 774-779 in Volume 2 of the Proceedings). A number of articles about this IEE guide and the issues associated with EMC-related functional safety have appeared during 2000 and 2001 in international trade journals, most recently in ITEM UPDATE 2001 (pages 52-59). The IEE has received many congratulations on this guide but so far has received no negative comments or suggestions for improvement - but of course it is far from perfect and the WG that wrote it expects to update and improve it during 2002 and 2003. All suggestions for corrections, additions, or improvements from emc-pstc members or anyone else are most welcome. If you don't want to share your input with the whole emc-pstc group please send it to me directly at keith.armstr...@cherryclough.com or cherryclo...@aol.com, or else send them directly to Robert Croll in the Policy Division of the IEE: rjecr...@iee.org.uk. Many thanks! Finally, I wish you all a wonderful 2002! Keith Armstrong Cherry Clough Consultants http://www.cherryclough.com
Re: EMC-related safety issues
I read in !emc-pstc that cherryclo...@aol.com wrote (in 123.96b6ec6.296 1b...@aol.com) about 'EMC-related safety issues', on Mon, 31 Dec 2001: (A key member of the IEC 61000-1-2 committee is a very senior safety expert and also a key member of the IEE Working Group that created this guide - helping to ensure compatibility between the two documents.) This very senior safety expert holds strong views that are not by any means shared by all of his colleagues, especially internationally. These strong views have, it is said, 'coloured' both the IEC TS and the IEE document. In the future work of the IEC, it is to be hoped that other equally senior experts will participate, so that a real international consensus is established BEFORE any standard is adopted unilaterally in Europe, either de facto or de jure. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk After swimming across the Hellespont, I felt like a Hero. --- 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.
EMC-related safety issues
Dear all There was a discussion about electromagnetic emissions and safety issues a couple of weeks ago which I only caught the tail end of, so I hope my comments below are relevant and useful. I would also like to make a plea for assistance. Spurious emissions and safety. Even if we ignore 'leakages' from intentional transmitters and industrial RF processing equipment (such as dielectric heaters) and also ignore biological (human health) hazards, it is quite clear that spurious emissions can increase the risks of some safety hazards. I have worked on problems where spurious emissions from microprocessor-based systems were interfering with safety-related radio communications, and also on a pulsed-laser welder that interfered with helicopter air traffic control radio communications. The laser could only be operated when the nearby airport was closed to helicopters during the night. Section 7 of the 'core' of the IEE's professional guidance document on 'EMC and Functional Safety' includes an example of a airplane passenger's laptop significantly affecting the pilot's compass reading. You can download this useful guide for free from www.iee.org.uk/Policy/Areas/Electro (note: this URL may be case sensitive). Another useful source of interference anecdotes is the Banana Skins column in the EMC and Compliance Journal, which may be read at www.compliance-club.com. The two most recent issues are 'live' on the site and the others can be read by searching its archives. The IEE's Guide on EMC and Functional Safety. This guide adopts much the same approach to dealing with EMC-related safety issues as IEC/TS 61000-1-2:2001 Electromagnetic Compatibility (EMC) - Part1-2: General - Methodology for the achievement of the functional safety of electrical and electronic equipment with regard to electromagnetic phenomena. (A key member of the IEC 61000-1-2 committee is a very senior safety expert and also a key member of the IEE Working Group that created this guide - helping to ensure compatibility between the two documents.) I understand that - after any modifications found necessary during its trial period - IEC/TS 61000-1-2 will probably become harmonised under the Low Voltage and Machinery safety directives. The IEE's guide on EMC and Functional Safety has been published for 18 months and downloaded by many thousands of professionals. I chaired a well-attended one-day seminar on it in London UK in February 2001 and presented a well-attended paper on it at the IEEE EMC International EMC Symposium in Montreal Canada last August (pages 774-779 in Volume 2 of the Proceedings). A number of articles about this IEE guide and the issues associated with EMC-related functional safety have appeared during 2000 and 2001 in international trade journals, most recently in ITEM UPDATE 2001 (pages 52-59). The IEE has received many congratulations on this guide but so far has received no negative comments or suggestions for improvement - but of course it is far from perfect and the WG that wrote it expects to update and improve it during 2002 and 2003. All suggestions for corrections, additions, or improvements from emc-pstc members or anyone else are most welcome. If you don't want to share your input with the whole emc-pstc group please send it to me directly at keith.armstr...@cherryclough.com or cherryclo...@aol.com, or else send them directly to Robert Croll in the Policy Division of the IEE: rjecr...@iee.org.uk. Many thanks! Finally, I wish you all a wonderful 2002! Keith Armstrong Cherry Clough Consultants http://www.cherryclough.com
