Re: Safety Critical Input Summary
Hi Lauren: There are different definitions for safety-critical component based on the different needs for identification of such components. I'd like to list a few, and then offer yet a different definition of a safety-critical component. 1. A safety-critical component is a component which appears in a safety report such as those produced by third-party safety certification houses. (Doug McKean) 2a. A safety-critical component is any component the failure of which would lead to a hazardous condition of either the product or the system. (Richard Woods, John Allen) 2b. A safety-critical component is either component in a two-component scheme intended to provide protection (against a hazardous condition) in the event of a fault in one of the components. (George Alspaugh) 3. A safety-critical component may be a specific construction, e.g., smooth, rounded edges, or color of wire insulation, or a specific rating, or a warning, etc., rather than a component. (Gregg Kervill, George Alspaugh) If you can't identify the hazard against which the safety- critical component provides protection AND how it provides the protection, then either the component is not safety- critical, or the safety function it provides is not known. There is one word that rarely appears in the discussion of safety: safeguard. A safeguard is a device or a scheme of construction which renders a product or system as safe. A safeguard has certain parameters which are critical to its effectiveness as a safeguard. Rather than identifying safety-critical components, we should be identifying the safeguards and their parameters applicable to the specific scheme or product. For example, Basic Insulation is a safeguard against electric shock. Its safety-critical parameters include voltage rating, dielectric withstand rating, and temperature rating. An enclosure may or may not be a safeguard, depending on the construction of the product. If the enclosure is a safeguard against anything, then one of its parameters is robustness sufficient to withstand the impact test. Depending on the hazard against which the enclosure is providing protection, there may be other applicable parameters. Another safeguard is the two, independent fixings of wire terminations where the wire carries a hazardous voltage (or is adjacent to hazardous voltage). So, which is a better description? The wire terminal is a critical component. Or: The wire terminal is provided with two, independent fixings. A warning is a safeguard in that it imposes a specified action on the part of the user. Its parameters include color, font, and size. (Gregg Kervill) A list of safety-critical components is largely useless because the safety function of the component and its safety-critical parameters are rarely identified. On the other hand, a list of safeguards must necessarily identify the hazard which the safeguard protects against. (And, safeguard avoids the problem of safety- critical feature and compliance-critical component identified by John Allen and Oscar Overton.) Best regards, 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 test table construction plans
David, On a similar note I had heard that an EUT shelter might demonstrate a 6 dB variation between wet and dry conditions, or dirty vs. clean (pressure cleaned) condition. Did the papers comment on wood properties? Perhaps identifying soft wood vs. hard wood, minerals absorbed during growth, wet vs. dry, or other conditioning situations? I have only seen a handful of labs, but they all had wooden tables (defacto standard for the times -- past?). I wonder if the standards were written around the convention of wooden tables? You've raised an interesting issue. Best regards, Don Umbdenstock Sensormatic -- From: Pommerenke, David[SMTP:davi...@ece.umr.edu] Reply To: Pommerenke, David Sent: Thursday, November 01, 2001 4:15 PM To: 'POWELL, DOUG'; EMC-PSTC (E-mail) Subject: RE: EMC test table construction plans Doug, For emissions and immunity you should not use any wood in the table. It will significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB for immunity up to 1 GHz) change the test result. My experience has shown that Styrofoam is basicly the best material. There are a couple of published papers on this issue. As surface material the following worked out fine: - Foamed PVC (rather stiff, low dielectric constant due to the foamed nature), maybe 4 mm thick. - PE sheet, maybe 2 mm thick. David Pommerenke -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, November 01, 2001 11:38 AM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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. --- 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:
Re: general product classification
Hello Stuart, Visit the Safety Link www.safetylink.com, then, using your browser's FIND function (Control F for IE or NetScape), input the term New Approach (Cooperative site This will take you to a link that delivers your query to the EU New Approach site. Upon arrival there, click on the link titled, Directives and Standards Then drop down to the Directive of interest to you (such as 73/23/EEC Low Voltage Directive) and select the associated link titled, Shortcuts to standards giving presumption of conformity on Low Voltage equipment This will take you to an extensive listing of standards associated with the 73/32/EEC. You can follow the same scheme for any directive. Regards, Art Michael P.S. Call me if you have difficulties following the above scheme (860) 344-1651 * * * * * * * * * * * * * * * * * * * * * * * International Product Safety Bookshop * * Check out our current offerings! * * http://www.safetylink.com/bookshop.html * * * * Now offering BSI's Books Reports* * including, World Electricity Supplies * * * * Another service of the Safety Link* * www.safetylink.com * * * * * * * * * * * * * * * * * * * * * * * On Thu, 1 Nov 2001, Stuart Lopata wrote: If I have product xyz (generic) how do I go about finding the relevant standards that it must comply with for EN-BS/IEC/ETSI (European)? Of course, simply by looking at the list of standards titles I can get somewhat of an idea if they are relevant. However, I cannot view their scope without buying the standard first. Any ideas? Sincerely, Stuart Lopata Rookie Compliance Engineer --- 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: Metrics
Hi, One metric that is missing is the cost of over-design. As we all know EMC design is not quite a precise science :) but it is relatively easy to make anything comply first time if cost, and size are ignored! Depending upon the cost sensitivity of the product you might not want to pass cleanly the first time, at least not by too much. I would look for evidence of a good EMC design plan which has a base line approach but also has one or more planned means for increasing or decreasing EMC controls. In my opinion this is a very important part of our jobs as design engineers. This could include place holders on a PCB for a series choke that are etch links that can be cut if the parts are needed, capacitor mounting pads or mounting even points on a chassis for a vent panel with smaller apertures. The key is to design for these possibilities, not try to fit them in later. What makes sense for a system the size of a room won't make sense for an ultra-low cost commodity item and visa versa. Such EMC plans permit the engineer to be creative without the risk of being seen as a poor performer. It can also pay off to the final product cost. I can think of one (at least!) creative solution that failed big time in my career but the cost benefits would have been very significant if it had worked - all went well simply because there was a painless though more expensive backup plan. Beware what metrics you set! They might have hidden costs. Colin.. -Original Message- From: wo...@sensormatic.com [mailto:wo...@sensormatic.com] Sent: Thursday, November 01, 2001 3:20 PM To: emc-p...@majordomo.ieee.org Subject:Metrics My management is asking each engineering group to devise and apply metrics to our department operations. I have struggled for a couple of years to devise meaningful metrics as applied to EMC and product safety compliance testing and certification , but with little success. Some ideas have been: * % of received products that are found to be fully compliant without design changes * elapsed test and certification time * defects per unit (for example, number of fixes required to be safety compliant) * hours of actual test time vs.standard test time What metrics are you using and how well are they working? Richard Woods Sensormatic Electronics --- 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: general product classification
CENELE lists the scope, or part of it, on its site http://www.cenelec.org/ For example, here is what they say about EN 55022: This standard applies to ITE as defined in 3.1. Procedures are given for the measurement of the levels of spurious signals generated by the lTE and limits are specified for the frequency range 9 kHz to 400 GHz for both Class A and Class B equipment. No measurements need be performed at frequencies where no limits are specified. The intention of this standard is to establish uniform requirements for the radio disturbance level of the equipment contained in the scope, to fix limits of disturbance, to describe methods of measurement and to standardize operating conditions and interpretation of results. Richard Woods Sensormatic Electronics -Original Message- From: Stuart Lopata [mailto:stu...@timcoengr.com] Sent: Thursday, November 01, 2001 4:00 PM To: emc Subject: general product classification If I have product xyz (generic) how do I go about finding the relevant standards that it must comply with for EN-BS/IEC/ETSI (European)? Of course, simply by looking at the list of standards titles I can get somewhat of an idea if they are relevant. However, I cannot view their scope without buying the standard first. Any ideas? Sincerely, Stuart Lopata Rookie Compliance Engineer --- 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: EMC test table construction plans
Doug, For emissions and immunity you should not use any wood in the table. It will significantly (+/-2 dB up to 1 GHz for emissions , more above, +/-10 dB for immunity up to 1 GHz) change the test result. My experience has shown that Styrofoam is basicly the best material. There are a couple of published papers on this issue. As surface material the following worked out fine: - Foamed PVC (rather stiff, low dielectric constant due to the foamed nature), maybe 4 mm thick. - PE sheet, maybe 2 mm thick. David Pommerenke -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, November 01, 2001 11:38 AM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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.
general product classification
If I have product xyz (generic) how do I go about finding the relevant standards that it must comply with for EN-BS/IEC/ETSI (European)? Of course, simply by looking at the list of standards titles I can get somewhat of an idea if they are relevant. However, I cannot view their scope without buying the standard first. Any ideas? Sincerely, Stuart Lopata Rookie Compliance Engineer --- 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: Have we lost something? was John Woodgate - RE: New EMC stan dards; now CISPR24/EN55024 query
A . . . naiveté! I remember those days . . . Break it to him/her gently. John Juhasz Fiber Options Bohemia, NY -Original Message- From: CE-test - Ing. Gert Gremmen - ce-marking and more... [mailto:cet...@cetest.nl] Sent: Thursday, November 01, 2001 2:54 PM To: Ken Javor; Gregg Kervill; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: RE: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query You are right ??? May I add the following quoted part of an email inquiry we received today from one reputable USA manufacturer I received today in my mail box : QUOTE I apologize for the delay in responding back to you, but my boss is informing me that we simply have to fill out the EC Type Declaration of Conformity and put the label on it. The system will then be ok to send out. No documentation is needed until the system itself is questioned by the authorities or the customer. If we do get questioned, what sort of documentation will I need. Especially if I have not got the system officially tested. END QUOTE ?? This is maybe just because their own philosophy about safety and spectrum protection exceeds the requirements of current standards .. Regards, Gert Gremmen, (Ing) ce-test, qualified testing === Web presence http://www.cetest.nl CE-shop http://www.cetest.nl/ce_shop.htm /-/ Compliance testing is our core business /-/ === -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor Sent: Thursday, November 01, 2001 6:05 PM To: Gregg Kervill; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: Re: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query My opinion only. There was a time when the reputation of a manufacturer or business in general was a very important part of the success of that company, and the honesty and integrity of that company, extending to high quality products, was the major part of a good reputation. That is part of a free-market economy. The rationale behind immunity standards (indeed, gov't enforced emission standards) is that the free-market place does not work and it is more efficient to impose external political control. This is untrue a priori but becomes a self-fulfilling prophecy: once you impose rigid governmental standards industry-wide, there is nothing to be gained by exceeding the standard performance and everything to be gained by finding ways to meet these limits in the most cost-effective way. In effect, industry-wide standards tend to make what might have been a unique product into a commodity to be purchased from the lowest priced vendor. In this way, gov't imposed standards are are an assault on the integrity of the marketplace and ultimately justify their imposition by destroying the integrity that previously existed, while destroying the perception of individual integrity on the part of the consumer. Here is a simple example that works in the USA. Sometime in the 1930s the Federal Deposit Insurance Corporation was formed to insure bank deposits. Banks still like to boast about how strong they are, but for the average depositor the strength of the bank (the quality of their loans) is a moot point of little or no interest. If the bank goes bust, they are insured by the Fed. One bank looks pretty much like another to the average depositor. -- From: Gregg Kervill gkerv...@eu-link.com To: 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query Date: Thu, Nov 1, 2001, 9:20 AM I agree whole heartedly with John's point.And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- However it is not so much a lack of standards but a lack of will and commitment to Quality designs that I believe is the problem. Back in the dark ages - long ago - one of my design jobs was with a company making industrial photo-electric controls. We checked out emissions on all of our products using a LW/MW/VHF radio and a TV. We checked out susceptibility by wiring a BIG contactor as a buzzer and put x-y caps between the open contact end of the coil and ground and neutral. IT wiped out radios for about 50 feet! (But was only used sparingly maybe less than 30 seconds a month) GOOD - meant the unit continued to function normally. That was my EMC practice during the 1970's. Product Safety followed a similar pattern Later I worked in a larger company that employed a few sages; although they may have been a little past their prime in terms of innovation they were wonderful mentors and ensured that
RE: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
Hmmm, Interesting point. I agree with Ken's assesment for the most part. Setting a minimum level for marketability levels the playing field (which governments like). But they lend the same customer credibility to the minimally compliant as the super compliant (which consumers may or may not like). It also lessens the incentive to innovate (which engineers hate). Perhaps a ranking system could be used similar to that used for crash testing automobiles. Any car that meets the government's minimum crash test rating can be sold. However, there are now star ratings given out for cars that meet and exceed the requirements. Anybody in the US who hasn't lived in a cave knows that the Ford Windstar has a 5 Star crash test rating. It's screamed all over the TV in commercials about 25 times a night. There you have it, an incentive for not only meeting the standards, but beating it. Maybe a sliding scale could be created that tracks the state of the art (compliance wise). Equipment could then be certified as level 1, level 2 ... up to level 5 5 Star if you want. Then, companies that meet and exceed the safety, emissions or immunity standard could claim 5 Star emissions compliance or 5 star safety compliance... If the scale is adjusted from time to time; when a company improves compliance performance, they would then raise the bar for the rest of the world. Interesting discussion. Got to get back to the ball and chain Chris Maxwell | Design Engineer - Optical Division email chris.maxw...@nettest.com | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | -Original Message- From: Ken Javor [SMTP:ken.ja...@emccompliance.com] Sent: Thursday, November 01, 2001 12:05 PM To: Gregg Kervill; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: Re: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query My opinion only. There was a time when the reputation of a manufacturer or business in general was a very important part of the success of that company, and the honesty and integrity of that company, extending to high quality products, was the major part of a good reputation. That is part of a free-market economy. The rationale behind immunity standards (indeed, gov't enforced emission standards) is that the free-market place does not work and it is more efficient to impose external political control. This is untrue a priori but becomes a self-fulfilling prophecy: once you impose rigid governmental standards industry-wide, there is nothing to be gained by exceeding the standard performance and everything to be gained by finding ways to meet these limits in the most cost-effective way. In effect, industry-wide standards tend to make what might have been a unique product into a commodity to be purchased from the lowest priced vendor. In this way, gov't imposed standards are are an assault on the integrity of the marketplace and ultimately justify their imposition by destroying the integrity that previously existed, while destroying the perception of individual integrity on the part of the consumer. Here is a simple example that works in the USA. Sometime in the 1930s the Federal Deposit Insurance Corporation was formed to insure bank deposits. Banks still like to boast about how strong they are, but for the average depositor the strength of the bank (the quality of their loans) is a moot point of little or no interest. If the bank goes bust, they are insured by the Fed. One bank looks pretty much like another to the average depositor. -- From: Gregg Kervill gkerv...@eu-link.com To: 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query Date: Thu, Nov 1, 2001, 9:20 AM I agree whole heartedly with John's point.And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- However it is not so much a lack of standards but a lack of will and commitment to Quality designs that I believe is the problem. Back in the dark ages - long ago - one of my design jobs was with a company making industrial photo-electric controls. We checked out emissions on all of our products using a LW/MW/VHF radio and a TV. We checked out susceptibility by wiring a BIG contactor as a buzzer and put x-y caps between the open contact end of the coil and ground and neutral. IT wiped out radios for about 50 feet! (But was only used sparingly maybe less than 30 seconds a month) GOOD - meant the unit continued to function normally. That was my EMC practice during the 1970's. Product Safety followed a similar pattern Later I worked in a larger company that
Metrics
My management is asking each engineering group to devise and apply metrics to our department operations. I have struggled for a couple of years to devise meaningful metrics as applied to EMC and product safety compliance testing and certification , but with little success. Some ideas have been: * % of received products that are found to be fully compliant without design changes * elapsed test and certification time * defects per unit (for example, number of fixes required to be safety compliant) * hours of actual test time vs.standard test time What metrics are you using and how well are they working? Richard Woods Sensormatic Electronics --- 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: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
I believe the philosophical debate is whether industry can take care of itself (a free market) or whether gov't must step in and take control. Regardless of the technical issues, dense spectrum occupancy/safety/whatever, industry standards can solve the issue. For instance, EN 55022 comes from CISPR 22. Why did it HAVE to be an EN? The work that went into the FCC CE and RE limits in this country were developed by an industry group, the Computer and Business Equipment Manufacturers' Association (CBEMA - now superseded by a TC working group). Why couldn't it have simply been an agreement within industry? I buy oil for my car that meets SAE requirements for weight and viscosity, etc. and if that oil were no good it would invalidate the warranty on my engine and this has all been worked out not within an industry but between industries... -- From: CE-test - Ing. Gert Gremmen - ce-marking and more... cet...@cetest.nl To: Ken Javor ken.ja...@emccompliance.com, Gregg Kervill gkerv...@eu-link.com, 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: RE: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query Date: Thu, Nov 1, 2001, 1:54 PM You are right ??? May I add the following quoted part of an email inquiry we received today from one reputable USA manufacturer I received today in my mail box : QUOTE I apologize for the delay in responding back to you, but my boss is informing me that we simply have to fill out the EC Type Declaration of Conformity and put the label on it. The system will then be ok to send out. No documentation is needed until the system itself is questioned by the authorities or the customer. If we do get questioned, what sort of documentation will I need. Especially if I have not got the system officially tested. END QUOTE ?? This is maybe just because their own philosophy about safety and spectrum protection exceeds the requirements of current standards . Regards, Gert Gremmen, (Ing) ce-test, qualified testing === Web presence http://www.cetest.nl CE-shop http://www.cetest.nl/ce_shop.htm /-/ Compliance testing is our core business /-/ === -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Ken Javor Sent: Thursday, November 01, 2001 6:05 PM To: Gregg Kervill; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: Re: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query My opinion only. There was a time when the reputation of a manufacturer or business in general was a very important part of the success of that company, and the honesty and integrity of that company, extending to high quality products, was the major part of a good reputation. That is part of a free-market economy. The rationale behind immunity standards (indeed, gov't enforced emission standards) is that the free-market place does not work and it is more efficient to impose external political control. This is untrue a priori but becomes a self-fulfilling prophecy: once you impose rigid governmental standards industry-wide, there is nothing to be gained by exceeding the standard performance and everything to be gained by finding ways to meet these limits in the most cost-effective way. In effect, industry-wide standards tend to make what might have been a unique product into a commodity to be purchased from the lowest priced vendor. In this way, gov't imposed standards are are an assault on the integrity of the marketplace and ultimately justify their imposition by destroying the integrity that previously existed, while destroying the perception of individual integrity on the part of the consumer. Here is a simple example that works in the USA. Sometime in the 1930s the Federal Deposit Insurance Corporation was formed to insure bank deposits. Banks still like to boast about how strong they are, but for the average depositor the strength of the bank (the quality of their loans) is a moot point of little or no interest. If the bank goes bust, they are insured by the Fed. One bank looks pretty much like another to the average depositor. -- From: Gregg Kervill gkerv...@eu-link.com To: 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query Date: Thu, Nov 1, 2001, 9:20 AM I agree whole heartedly with John's point.And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- However it is not so much a lack of standards but a lack of will and commitment to Quality designs that I believe is the problem.
Safety Critical Input Summary
All, Thanks for the many inputs on the idea of Safety Critical Components. For those that are interested, here is a general summary of the input I recieved. Safety vs. Compliance = A key issue that should be brought into the analysis of safety critical parts is that many particular aspects in designs are driven by a need to comply to specific standards rather than a an original analysis of whether the aspect is needed for safety. Often, aspects of design that are provided in order to achieve compliance are confused with aspects that are needed for safety because of the impression (right or wrong) that the overall goal of the standard is to achieve an acceptable level of safety. For example, the NEC constrains only the colors of line, neutral and grounding conductors. NFPA 79 constrains these conductors as well as many other regimes such as DC power conductors and DC grounded return conductors. So, it might be inferred that wire color is a safety critical issue. It is doubtful one would argue that, generally, wire carrying potentially hazardous voltages are NOT safety critical. However, a more reasonable debate might arise over lenses used to give color to warning lights. Is the color of the lens a safety critical issue, or only presence or absence of a light? The Error of Focusing only on Components A key method to identify something as safety critical is to do an FMEA (Failure Modes/Methods and Effects Analysis). If the failure of the object of the analysis can cause significant harm to the target of concern then the object is safety critical. Of course, significant harm is a subjective decision, and the target of concern will vary (i.e. passers by, service personnel, the environment, etc...) The point for now is that the object of analysis may not be a single component. It may be a feature, a system, an assembly. The Importance of Context = One can not identify a component as safety critical without understanding the system/environment it is used in. For example, a hookup wire may only be safety critical when it is used in a hazardous voltage circuit. And, along a similar line of thought, a component that is TYPCIALLY used in a safety critical context, can be used in a context in which it is not safety critical. For example, a 12 AWG wire with 300V rated insulation is not safety critical when it is used in a 5 volt current limited circuit. Negative Safety Contribution = Some respondents noted components that are safety critical because they can cause harm or could be designed incorrectly. For example, in this line of thinking, a panel could be a safety critical part if it has (or could have) sharp edges or excessive weight. Normal Operation and Failure Modes == It was also noted that some safety critical parts only play their role during failure modes. During normal operations they have no significant function. Certainly this is an important observation, but becomes dependent on a more subjective concept of reasonably foreseeable. Already High Risk Industries = The meaning of safety critical can be affected by the overall context of risk that exists to personnel. In an industry where any injury is not acceptable, safety critical has a very conservative interpretation. In other industries, where high risk is more acceptable, safety critical can have a very liberal meaning such as this (taken from a web site) Safety Critical Component means any component whose failure to perform could cause the failure of, or affect the operation of a Life Support Device Is it on a List? Some respondents are, presumably, in a position of relying on their product assessors for the definition of safety critical. For them a part is safety critical only if it has been place on a list of safety critical parts. Their own judgement does not, apparently, play a significant role in creating this list. Other's noted that a list is a key communication tool for safety critical parts after they have been identified. Single Fault Failure When delving into theoretical discussions of what parts contribute to critical safety for potential failure scenarios, a boundary is required to keep the discussion practical. The concept of single fault is key in this. That is to say, there seems to be an accepted obligation to protect personnel from reasonably foreseeable single fault failures, but not all conceivable multi-fault scenarios...even when the individual faults are reasonably foreseeable. Relaxed Safety for Certain Groups == Surprisingly, there was little suggestion that the status of safety critical depended on the population (i.e. passer by, operator, service or maintenance) that was interacting with the product. The Most General Definition
Re: EMC test table construction plans
Hi Doug, The following expresses some of my experiences. I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). Standard 2x2 or 2x4 and 1/2 plywood should suffice. 2) I want to minimize metalic fastners. What I've used in the past are wood dowels and wood glue. This takes some time, but the table is extremely durable. 3) I would like to make it a pivoting table (not motorized). I have used a large lazy-susan mechanism (very low profile and w/ball bearings). Teflon pads were used to provide rotational stability and ease of rotation. 4) Height is 80 cm. Just cut the wood to fit. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. A round piece of 1/2 plywood should suffice (they can come pre-cut in 36 and 48 diameters). I've never had to replace a table top. 6) Suggestions on length width? I would not recommend any horizontal dimension greater than 60 for table stability. All this material is commonly available and can be purchased at places like Home Depot, Lowes, your local lumber retailer, etc. As a convenience for measurement repeatability, I placed angular markings on the table top in 10 and 45 degree increments. I hope this helps. Best regards, Ron Pickard rpick...@hypercom.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: 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: Difference between SA and Receiver
What are some of the most cost effective CISRP 16 compliant receivers/SAs available today? Richard Woods Sensormatic Electronics -Original Message- From: Sundstrom Michael (NMP-RD/Dallas) [mailto:michael.sundst...@nokia.com] Sent: Thursday, November 01, 2001 2:08 PM To: 'Ken Javor'; Muriel Bittencourt de Liz; EMC-PSTC List Subject: RE: Difference between SA and Receiver Most analyzers are not CISPR 16 compliant. Receivers are always easer to read QP and Avg. directly. If you can pass the CISPR limits with a peak reading (analyzer), you can most definitely pass the QP / Avg. limits with a receiver. For official testing a compliant (CISPR 16) device is always needed to measure with. Michael Sundstrom NOKIA TCC Dallas / EMC ofc: (972) 374-1462 cell: (817) 917-5021 amateur call: KB5UKT -Original Message- From: ext Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, November 01, 2001 10:21 AM To: Muriel Bittencourt de Liz; EMC-PSTC List Subject: Re: Difference between SA and Receiver Assuming 50/60 Hz power and CE measurements made at a CISPR 16 LISN EMI port, the only possible difference I can think of is increased probability of 50/60 Hz overload with a spectrum analyzer capable of measurements that low. If your spectrum analyzer doesn't tune below 9 kHz, that shouldn't be a problem. In any case, the CE limits are such that you can easily afford to put a 20 dB pad on the LISN port and that should stop any overload effect. An EMI receiver provides several features different than an analyzer: increased sensitivity, front end filtering (preselection), and (typically) a variety of detection modes, although spectrum analyzers are catching up in this regards. If you need to make average measurements, this is more easily accomplished with an EMI receiver. -- From: Muriel Bittencourt de Liz mur...@eel.ufsc.br To: EMC-PSTC List emc-p...@ieee.org Subject: Difference between SA and Receiver Date: Thu, Nov 1, 2001, 8:15 AM Hello Group, What are the differences that result using: 1. A Spectrum Analyzer (SA) or 2. A Receiver When I make measurements of conducted emissions of an equipment?? Best Regards Muriel --- 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. --- 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
RE: EN 55022 limits
Gert, You are absolutely correct. 1/R does not work between 3 and 10 meters and testing a product at 3 meters using this factor can lead to unpleasant surprises at 10 meters. However, good, bad or indifferent, CISPR 22 uses it when testing at distances other than 10 meters. Caveat engineer. Ghery -Original Message- From: CE-test - Ing. Gert Gremmen - ce-marking and more... [mailto:cet...@cetest.nl] Sent: Thursday, November 01, 2001 11:54 AM To: Pettit, Ghery; 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: RE: EN 55022 limits Recent investigations have shown that in spite of this rule of thumb about 10.5 dB (10) adding to the limits from 10 - 3 meters is not correct. A better correlation was found to be approx 4 dB only. This is of course due to the sizes of real life EUT and cabling, related to the antenna size and the angle at which signal arrive at the antenna. The vector some of the radiation from two radiation sources in your EUT might add up differently at 3 meters then at 10 meters. My personal experience is that this is true especially for lower frequencies say between 30-80 Mhz. For the moment several standards allow this conversion rule, however, in Europe where one should comply to essential requirements, and the standards result is not decisive (only presumptive ?!?) authorities might decide your product that passes close to the limit at 3m is at fault really. In general, drawing conclusions between 0 and 10 dB is rather dangerous, if your results are not statistically significant and or performed DUE DILIGENCE in establishing the emission characteristics of your equipment. Regards, Gert Gremmen, (Ing) ce-test, qualified testing === Web presence http://www.cetest.nl CE-shop http://www.cetest.nl/ce_shop.htm /-/ Compliance testing is our core business /-/ === -Original Message- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Pettit, Ghery Sent: Thursday, November 01, 2001 6:02 PM To: 'John Woodgate'; emc-p...@majordomo.ieee.org Subject: RE: EN 55022 limits John, I believe that is a major part of the reason. It certainly was one of the arguments that was used to kill a recent proposal in CISPR to create specific limits at 3 meters for both class A and class B devices. The proposal had a size limit for the EUT, but died anyway. Ghery -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, October 31, 2001 11:18 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN 55022 limits I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B518@ORSMSX108) about 'EN 55022 limits', on Wed, 31 Oct 2001: The note in CISPR 22 that allows testing at alternate distances applies only to class B products. What is the justification for not allowing it for Class A? Is it assumed that Class A products might be larger? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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. --- 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:
Re: EMC test table construction plans
I read in !emc-pstc that POWELL, DOUG doug.pow...@aei.com wrote (in b44016f6854cd511a6470003476b45e4381...@exchange.aei.com) about 'EMC test table construction plans', on Thu, 1 Nov 2001: 1) I will be testing products that weight up to 200 Lbs (91 kg). No problem 2) I want to minimize metalic fastners. No problem 3) I would like to make it a pivoting table (not motorized). Do you mean rotatable? 4) Height is 80 cm. No problem 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. It needs support at intervals of 50 cm in one direction to safely support 200 lb. 6) Suggestions on length width? Bigger than the biggest unit you want to put on it? 1 m by 0.5 m might be convenient. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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 test table construction plans
Doug, I am not sure what you mean by pivoting. We created a table that has the features listed below and include knock-down for flat storage. For a small square table, we used 3/4 plywood for top and legs. The legs were slotted and hollowed, and fit together in a perpendicular slot to slot fashion. A full size table uses the legs for the small square table plus one more long leg. For both the square table and full size table, the table is guided into position by glued-on blocks. We typically don't test 200 lb devices; but I have stood on the table. You might feel more comfortable with 1 plywood. See crude sketch below for a better concept. Table sketch.doc We place this table on a flush-mount turn-table for the rotational requirements. This table is light weight, easily stored, takes up minimal space in storage, strong, and is built with no metallic parts. Best regards, Don Umbdenstock Sensormatic -- From: POWELL, DOUG[SMTP:doug.pow...@aei.com] Reply To: POWELL, DOUG Sent: Thursday, November 01, 2001 12:37 PM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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. Table sketch.doc Description: MS-Word document
Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
I read in !emc-pstc that Ken Javor ken.ja...@emccompliance.com wrote (in 20011101170447.RTSO12020.femail23.sdc1.sfba.home.com@[65.11.150.27] ) about 'Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query', on Thu, 1 Nov 2001: My opinion only. No, it is shared by a significant number of others. There was a time when the reputation of a manufacturer or business in general was a very important part of the success of that company, and the honesty and integrity of that company, extending to high quality products, was the major part of a good reputation. That is part of a free-market economy. The rationale behind immunity standards (indeed, gov't enforced emission standards) is that the free-market place does not work and it is more efficient to impose external political control. It doesn't work well for consumer electronic products, because the purchasers would not understand claims of, for example, superior EMC performance. In fact, in the present paranoid atmosphere about 'radiation', even a mention of EMC terminology might provoke mass panic! This is untrue a priori but becomes a self-fulfilling prophecy: once you impose rigid governmental standards industry-wide, there is nothing to be gained by exceeding the standard performance and everything to be gained by finding ways to meet these limits in the most cost-effective way. In effect, industry-wide standards tend to make what might have been a unique product into a commodity to be purchased from the lowest priced vendor. In this way, gov't imposed standards are are an assault on the integrity of the marketplace and ultimately justify their imposition by destroying the integrity that previously existed, while destroying the perception of individual integrity on the part of the consumer. Your argument is far less easy to counter if you restrict it to 'professional' equipment, for which the purchasers may be assumed to understand the technical specification of the product. EN55103-2 imposes no immunity limits, it simply specifies methods of measurement and requires the manufacturer to disclose the immunity performance of the product. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: New EMC standards; now CISPR24/EN55024 query
I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B52E@ORSMSX108) about 'New EMC standards; now CISPR24/EN55024 query', on Thu, 1 Nov 2001: I feel that immunity is a product quality issue and is best left to a manufacturer as a customer satisfaction issue and should not be a regulatory matter. A lot of people agree with you, but in Europe we don't have a choice - it IS a regulatory matter and the SLIM review of the Directive decided not to recommend changing that. In Germany, there was a major problem of lack of immunity in TV sets in the 70s and 80s. Consequently, the German authorities do not favour relaxation in this matter. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: classification for part 18
I don't know about Part 18, but because the modem connects to the telecom network, it would have to comply with Part 68. John P. Wagner Regulatory Compliance Mandatory Standards AVAYA Strategic Standards. 1300 W. 120th Ave, Room B3-D16 Phone/Fax: (303) 538-4241 johnwag...@avaya.com -- From: Stuart Lopata[SMTP:stu...@timcoengr.com] Reply To: Stuart Lopata Sent: Thursday, November 01, 2001 9:38 AM To: emc Subject: classification for part 18 Does a medical device that connects to a blood pressure unit and sends info over the phone lines need to be tested under part 18. I think not, however, it is a medical device. Please comment. Sincerely, Stuart Lopata --- 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: Difference between SA and Receiver
Most analyzers are not CISPR 16 compliant. Receivers are always easer to read QP and Avg. directly. If you can pass the CISPR limits with a peak reading (analyzer), you can most definitely pass the QP / Avg. limits with a receiver. For official testing a compliant (CISPR 16) device is always needed to measure with. Michael Sundstrom NOKIA TCC Dallas / EMC ofc: (972) 374-1462 cell: (817) 917-5021 amateur call: KB5UKT -Original Message- From: ext Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, November 01, 2001 10:21 AM To: Muriel Bittencourt de Liz; EMC-PSTC List Subject: Re: Difference between SA and Receiver Assuming 50/60 Hz power and CE measurements made at a CISPR 16 LISN EMI port, the only possible difference I can think of is increased probability of 50/60 Hz overload with a spectrum analyzer capable of measurements that low. If your spectrum analyzer doesn't tune below 9 kHz, that shouldn't be a problem. In any case, the CE limits are such that you can easily afford to put a 20 dB pad on the LISN port and that should stop any overload effect. An EMI receiver provides several features different than an analyzer: increased sensitivity, front end filtering (preselection), and (typically) a variety of detection modes, although spectrum analyzers are catching up in this regards. If you need to make average measurements, this is more easily accomplished with an EMI receiver. -- From: Muriel Bittencourt de Liz mur...@eel.ufsc.br To: EMC-PSTC List emc-p...@ieee.org Subject: Difference between SA and Receiver Date: Thu, Nov 1, 2001, 8:15 AM Hello Group, What are the differences that result using: 1. A Spectrum Analyzer (SA) or 2. A Receiver When I make measurements of conducted emissions of an equipment?? Best Regards Muriel --- 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. --- 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.
Receiver calibration
Can anyone point me in the direction of vendors/labs that can calibrate a Schaffner receiver? Best Regds Bayode --- 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: Difference between SA and Receiver
I guess the most significant difference is that analyzers normally don't have a Quasipeak detector which is required for this measurements Best Regards Lothar Schmidt Technical Manager EMC/Radio BQB CETECOM Inc. 411 Dixon Landing Road Milpitas, CA 95035 * +1 408 586 6214 * +1 408 586 6299 -Original Message- From: Ken Javor [mailto:ken.ja...@emccompliance.com] Sent: Thursday, November 01, 2001 8:21 AM To: Muriel Bittencourt de Liz; EMC-PSTC List Subject: Re: Difference between SA and Receiver Assuming 50/60 Hz power and CE measurements made at a CISPR 16 LISN EMI port, the only possible difference I can think of is increased probability of 50/60 Hz overload with a spectrum analyzer capable of measurements that low. If your spectrum analyzer doesn't tune below 9 kHz, that shouldn't be a problem. In any case, the CE limits are such that you can easily afford to put a 20 dB pad on the LISN port and that should stop any overload effect. An EMI receiver provides several features different than an analyzer: increased sensitivity, front end filtering (preselection), and (typically) a variety of detection modes, although spectrum analyzers are catching up in this regards. If you need to make average measurements, this is more easily accomplished with an EMI receiver. -- From: Muriel Bittencourt de Liz mur...@eel.ufsc.br To: EMC-PSTC List emc-p...@ieee.org Subject: Difference between SA and Receiver Date: Thu, Nov 1, 2001, 8:15 AM Hello Group, What are the differences that result using: 1. A Spectrum Analyzer (SA) or 2. A Receiver When I make measurements of conducted emissions of an equipment?? Best Regards Muriel --- 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. --- 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 test table construction plans
Doug, You might want to look at a paper that was presented at the Montreal IEEE EMC Symposium by HP on measurements that they made on a table when starting to test above 1 GHz. As you know, the FCC (ANSI C63.4) and CISPR 22 requirements simply call out that the table should be non-conducting. That's about all that is said. Measurements made by HP in Vancouver, WA show that this might just be an inadequate specification for the table due to reflections from the table/air boundary. Their table was wood with no metal fasteners of any kind, with a plastic sheet on the top. It meets the non-conducting requirement, but demonstrated that this minimal standard is inadequate to ensure accurate and repeatable results. I am certain that the results of their tests will cause some interesting discussions in various standards bodies over the next few years. That said, a wood or fiberglass table should meet your needs quite nicely. I've seen a number of construction techniques over the years that have all had minimal metal content (our tables have two swivel casters under the legs at one end and metal axels for the wheels at the other end as their total metal content). These range from all wood, to PCV pipe frame with a wood top to fiberglass construction. All are sturdy enough to hold 200 pounds and all are non-conductive. I'm not sure what to suggest for your swivel mount, but I have seen turntables built with a single metal pivot in the middle with a race of pool balls used for ball bearings further out on the table. Quick, simple and elegant. Non-conductive, except for the pivot in the middle. Good luck and have fun. Based on HP's paper, I suspect that a lot of us will be building new tables of a yet to be determined material in the next few years. Should make for some interesting conversations. Ghery Pettit Intel -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Thursday, November 01, 2001 9:38 AM To: EMC-PSTC (E-mail) Subject: EMC test table construction plans Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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: CENELEC Ammendments
I did find a lower cost alternative - IEC. At least when the CENELEC standard is identical with the IEC standard. The cost of the amendments are about half that of what I could find elsewhere and they are downloadable. Richard Woods Sensormatic Electronics -Original Message- From: Ron Pickard [mailto:rpick...@hypercom.com] Sent: Wednesday, October 31, 2001 3:39 PM To: wo...@sensormatic.com Cc: emc-p...@ieee.org Subject: Re: CENELEC Ammendments Hi Richard, You might want to try the following. Global Engineering Documents: http://global.ihs.com/ ANSI: http://web.ansi.org/ Pro's 7 Con's. ANSI is more likely to have separate amendments, documents that are generally less expensive, and have more documents in electronic format. Global will have the document that you're looking for most of the time, but will likely be only in paper format (hardcopy). Both have document search facilities. Good luck in your search. Best regards, Ron Pickard rpick...@hypercom.com wo...@sensormatic.com Sent by: To: emc-p...@majordomo.ieee.org owner-emc-pstc@majordomcc: o.ieee.org Subject: CENELEC Ammendments 10/31/01 12:16 PM Please respond to WOODS Where can I obtain an amendment to a CENELEC standard? I am spending a small fortune having to buy the complete amended standard from BSI every time it is revised. Richard Woods Sensormatic Electronics --- 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.
EMC test table construction plans
Hello all, I plan to construct my own insulated EMC test table for a 5 meter chamber. Seems simple enough to do and I could easily come up with something. I thought I might first ask for input from those of you in the discussion group who have experience or maybe even construction plans. Here are some features I want: 1) I will be testing products that weight up to 200 Lbs (91 kg). 2) I want to minimize metalic fastners. 3) I would like to make it a pivoting table (not motorized). 4) Height is 80 cm. 5) The surface should be replacable if it gets badly worn or scarred. I'm thinking of using hardboard. 6) Suggestions on length width? -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- 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: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
My opinion only. There was a time when the reputation of a manufacturer or business in general was a very important part of the success of that company, and the honesty and integrity of that company, extending to high quality products, was the major part of a good reputation. That is part of a free-market economy. The rationale behind immunity standards (indeed, gov't enforced emission standards) is that the free-market place does not work and it is more efficient to impose external political control. This is untrue a priori but becomes a self-fulfilling prophecy: once you impose rigid governmental standards industry-wide, there is nothing to be gained by exceeding the standard performance and everything to be gained by finding ways to meet these limits in the most cost-effective way. In effect, industry-wide standards tend to make what might have been a unique product into a commodity to be purchased from the lowest priced vendor. In this way, gov't imposed standards are are an assault on the integrity of the marketplace and ultimately justify their imposition by destroying the integrity that previously existed, while destroying the perception of individual integrity on the part of the consumer. Here is a simple example that works in the USA. Sometime in the 1930s the Federal Deposit Insurance Corporation was formed to insure bank deposits. Banks still like to boast about how strong they are, but for the average depositor the strength of the bank (the quality of their loans) is a moot point of little or no interest. If the bank goes bust, they are insured by the Fed. One bank looks pretty much like another to the average depositor. -- From: Gregg Kervill gkerv...@eu-link.com To: 'John Woodgate' j...@jmwa.demon.co.uk, emc-p...@majordomo.ieee.org Subject: Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query Date: Thu, Nov 1, 2001, 9:20 AM I agree whole heartedly with John's point.And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- However it is not so much a lack of standards but a lack of will and commitment to Quality designs that I believe is the problem. Back in the dark ages - long ago - one of my design jobs was with a company making industrial photo-electric controls. We checked out emissions on all of our products using a LW/MW/VHF radio and a TV. We checked out susceptibility by wiring a BIG contactor as a buzzer and put x-y caps between the open contact end of the coil and ground and neutral. IT wiped out radios for about 50 feet! (But was only used sparingly maybe less than 30 seconds a month) GOOD - meant the unit continued to function normally. That was my EMC practice during the 1970's. Product Safety followed a similar pattern Later I worked in a larger company that employed a few sages; although they may have been a little past their prime in terms of innovation they were wonderful mentors and ensured that we did not kill anyone with our designs! In the same way that nurses protect patients from newly appointed doctors. During the last 10 years the mentors seem to have be down-sized (due to efficiencies) - Old Traditional (empirical) practices are displaced - standards (safety and EMC) are seen as intrusive and an excuse to design down to minimal requirements (at best) or as a challenge to the integrity (dare I say manhood) of designers. During my 20 years in RD I did some very dumb things and designed several 'iffy power supplies - I know now that they are non-compliance but a few escaped into the market place. Take away the mentors - allow companies to Self Assessment and Self Certification in Safety are will things get better or worse. Do we need to direct a change of design culture? Is there a need for a recognized EMC or safety credential? DISCUSS... Gregg Eurolink Ltd. -One Link-199 Countries P.O. Box 310 Reedville, Virginia 22539 Phone: (804) 453-3141 Fax: (804) 453-9039 Web:www.eu-link.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: 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: EN 55022 limits
John, I believe that is a major part of the reason. It certainly was one of the arguments that was used to kill a recent proposal in CISPR to create specific limits at 3 meters for both class A and class B devices. The proposal had a size limit for the EUT, but died anyway. Ghery -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, October 31, 2001 11:18 PM To: emc-p...@majordomo.ieee.org Subject: Re: EN 55022 limits I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B518@ORSMSX108) about 'EN 55022 limits', on Wed, 31 Oct 2001: The note in CISPR 22 that allows testing at alternate distances applies only to class B products. What is the justification for not allowing it for Class A? Is it assumed that Class A products might be larger? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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.
Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
I read in !emc-pstc that Gregg Kervill gkerv...@eu-link.com wrote (in 002f01c162e8$ca3f3800$7300a8c0@MENHADEN) about 'Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query', on Thu, 1 Nov 2001: Is there a need for a recognized EMC or safety credential? York University in UK offers a (post-graduate?) qualification in EMC. Others may as well, by now. I don't know of one for product safety. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: New EMC standards; now CISPR24/EN55024 query
John, I have no argument with you on that point. A product that will not function in its intended environment is rather useless. However, as an anarchist Yank (well, that might be putting it a bit too strongly, but I do believe in limited government - a topic for some other forum), I feel that immunity is a product quality issue and is best left to a manufacturer as a customer satisfaction issue and should not be a regulatory matter. The regulators have a vested interest in protecting licensed users of the radio spectrum, so emissions limits are in order. Immunity requirements do not serve a similar function, so should be left to the customer and vendor. In the U.S. the only commercial immunity requirements are contained in the NEBS documents for telco equipment. A customer written and administered requirement that works quite well. Ghery Pettit -Original Message- From: John Woodgate [mailto:j...@jmwa.demon.co.uk] Sent: Wednesday, October 31, 2001 11:28 PM To: emc-p...@majordomo.ieee.org Subject: Re: New EMC standards; now CISPR24/EN55024 query I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B526@ORSMSX108) about 'New EMC standards; now CISPR24/EN55024 query', on Wed, 31 Oct 2001: Even then, changes in CISPR documents occur at glacial speed. This isn't always a bad thing, either. Things are changing, even in CISPR. And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: Difference between SA and Receiver
Muriel, Unless your spectrum analyzer is equipped with a tracking pre-selector, or a high pass filter, you run the risk of high level emissions at frequencies below 150 kHz desensitizing the front end. This will result in readings that are lower than the actual levels. I remember seeing this a number of years ago when testing to the old German standards that had us doing power line conducted emissions measurements down to 9 kHz. Two different labs claimed that a particular product passed, but when I tested it with a receiver, I failed it. Turns out they were using spectrum analyzers and when I repeated the measurement with a spectrum analyzer, I got the same results they did. I've used nothing but receivers for PLC testing ever since. A tracking pre-selector in front of a spectrum analyzer would work just as well, however. Ghery Pettit Intel -Original Message- From: Muriel Bittencourt de Liz [mailto:mur...@eel.ufsc.br] Sent: Thursday, November 01, 2001 6:16 AM To: EMC-PSTC List Subject: Difference between SA and Receiver Hello Group, What are the differences that result using: 1. A Spectrum Analyzer (SA) or 2. A Receiver When I make measurements of conducted emissions of an equipment?? Best Regards Muriel --- 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.
classification for part 18
Does a medical device that connects to a blood pressure unit and sends info over the phone lines need to be tested under part 18. I think not, however, it is a medical device. Please comment. Sincerely, Stuart Lopata --- 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 Measurement Uncertainty
Howdy all, I hate to ask this loaded question. But, I must. For accredited EMC labs how are you addressing uncertainty? I've read NIS 81, NIST TN 1297, a few papers published in the IEEE Symposium Notes, and my Statistics text book. My basic question, is there an easy, step-by-step method for doing this? Let me take the radiated site as an example: In general, radiated sites use the following devices for which we need to determine uncertainty (there are others such as 3dB pads and external preamplifiers, but lets keep it simple): EMI Receiver Antenna(s) Coaxial cables Site (NSA) 1) The EMI RCVR has an uncertainty reported by the cal lab. 2) The antenna(s) have an uncertainty reported (in our case) from by the cal lab. 3) The coaxial cable cal is performed in house using the above RCVR 4) The NSA is performed using the RCVR and the in house cal'ed coaxial cable. Seems to me the RCVR uncertainty value is as reported by the cal lab. Same is true for the antenna. However, the coaxial cables uncertainty would a factor of the RCVR uncertainty plus (Root Sum Square), of the variation of the coaxial cable measurements (several sets identical data typically). The NSA uncertainty, would be the RSS deviation from theoretical NSA, the coaxial, RCVR, and antenna uncertainties. This would be done for 3 and 10 meters and horizontal and vertical. And finally the total radiated emissions uncertainty would be the RSS of all uncertainties above 1-4. I am determining uncertainty for each component using the following method: confidence of 95% .05(SDEV) / (sqr N) That is, confidence level of 95% times the standard deviation all over the square root of the number of measurements Any comments or direction would be greatly appreciated. regards David Spencer --- 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.
NVLAP compared to A2LA
Hello Group, I am also looking at the lab accreditation process and would appreciate your opinions on NVLAP compared to A2LA. Please email me directly. Responses will be kept confidential. Regards, Don MacArthur -- This e-mail may contain SEL confidential information. The opinions expressed are not necessarily those of SEL. Any unauthorized disclosure, distribution or other use is prohibited. If you received this e-mail in error, please notify the sender, permanently delete it, and destroy any printout. Thank you. --- 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.
Have we lost something? was John Woodgate - RE: New EMC standards; now CISPR24/EN55024 query
I agree whole heartedly with John's point.And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- However it is not so much a lack of standards but a lack of will and commitment to Quality designs that I believe is the problem. Back in the dark ages - long ago - one of my design jobs was with a company making industrial photo-electric controls. We checked out emissions on all of our products using a LW/MW/VHF radio and a TV. We checked out susceptibility by wiring a BIG contactor as a buzzer and put x-y caps between the open contact end of the coil and ground and neutral. IT wiped out radios for about 50 feet! (But was only used sparingly maybe less than 30 seconds a month) GOOD - meant the unit continued to function normally. That was my EMC practice during the 1970's. Product Safety followed a similar pattern Later I worked in a larger company that employed a few sages; although they may have been a little past their prime in terms of innovation they were wonderful mentors and ensured that we did not kill anyone with our designs! In the same way that nurses protect patients from newly appointed doctors. During the last 10 years the mentors seem to have be down-sized (due to efficiencies) - Old Traditional (empirical) practices are displaced - standards (safety and EMC) are seen as intrusive and an excuse to design down to minimal requirements (at best) or as a challenge to the integrity (dare I say manhood) of designers. During my 20 years in RD I did some very dumb things and designed several 'iffy power supplies - I know now that they are non-compliance but a few escaped into the market place. Take away the mentors - allow companies to Self Assessment and Self Certification in Safety are will things get better or worse. Do we need to direct a change of design culture? Is there a need for a recognized EMC or safety credential? DISCUSS... Gregg Eurolink Ltd. -One Link-199 Countries P.O. Box 310 Reedville, Virginia 22539 Phone: (804) 453-3141 Fax: (804) 453-9039 Web:www.eu-link.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: 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: EN 55022 limits
My opinion only. The reason for not allowing the 3 m test for Class A is that the limit is higher than for Class B so the rationale for moving in to 3 m separation and raising the limit is not as persuasive. -- From: John Woodgate j...@jmwa.demon.co.uk To: emc-p...@majordomo.ieee.org Subject: Re: EN 55022 limits Date: Thu, Nov 1, 2001, 1:18 AM I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B518@ORSMSX108) about 'EN 55022 limits', on Wed, 31 Oct 2001: The note in CISPR 22 that allows testing at alternate distances applies only to class B products. What is the justification for not allowing it for Class A? Is it assumed that Class A products might be larger? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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.
Difference between SA and Receiver
Hello Group, What are the differences that result using: 1. A Spectrum Analyzer (SA) or 2. A Receiver When I make measurements of conducted emissions of an equipment?? Best Regards Muriel --- 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.
European Hydraulic Control Valve Requrierments
Dear All, Anyone one knows what CE-IIA or CE-IIB mean? I assume Class IIA or Class IIB. Is this from the Pressure Equipment Directive? The product in question is an automatic hydraulic control valve. Regards, This e-mail message may contain privileged or confidential information. If you are not the intended recipient, you may not disclose, use, disseminate, distribute, copy or rely upon this message or attachment in any way. If you received this e-mail message in error, please return by forwarding the message and its attachments to the sender. PETER S. MERGUERIAN Technical Director I.T.L. (Product Testing) Ltd. 26 Hacharoshet St., POB 211 Or Yehuda 60251, Israel Tel: + 972-(0)3-5339022 Fax: + 972-(0)3-5339019 Mobile: + 972-(0)54-838175 --- 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: Radiated Emissions EUT Config
I read in !emc-pstc that Scott Lemon sle...@caspiannetworks.com wrote (in 3be064c5.e48c3...@caspiannetworks.com) about 'Radiated Emissions EUT Config', on Wed, 31 Oct 2001: I am in search of opinions regarding the acceptable EUT configuration for radiated emissions testing. If a system is comprised of one or more independent shelf-level products (e.g. one shelf in a rack or several racks full), at what level is it acceptable to test? Assume that the system can be sold as one independent fully functional shelf or as numerous interconnected shelves (interconnection just increasing system capacity). For example, one shelf could be sold and deployed, then 6 months later another shelf added (cabled up to the first), and so on, etc. 1. Would it be acceptable to test at the shelf level? 2. If not, where is the line drawn? Two? Ten? In a typical CO you may see racks and racks of the same equipment shelves/chassis - chances are, they were not all tested together - where is it reasonable to stop? FCC (ref. ANSI C63.4)/EN300386/GR1089 have some guidance, differing slightly, but not clear. Any and all opinions/experiences from the group are welcome. Adopt a 'real world' approach. If the separate products could be simply placed side-by-side or stacked on a table or shelf, instead of being mounted in a rack, you do not need to measure the rack as a whole. See IEC/EN61000-3-2, which says this explicitly. In Europe, the question should not arise, because since each product can be marketed separately, each requires to conform to applicable standards and to be CE marked. Assembly into a rack could be carried out by anyone - an installer or end-user - and clearly to then require re-testing would be unrealistic. The only snag is that if the **manufacturer** assembles the products into a rack, **and then markets the rack as a single article of commerce, i.e. at an inclusive price**, then it is classed as a system under the EMC Directive and DOES need to conform as a whole to the applicable standards, unless the product standard says differently, as CISPR15/EN55015 does for dimmers. Large assemblies and aggregations are almost always more or less 'site- specific' and are thus 'installations' under the EMC Directive. Installations need no a priori testing but the installation must be in accordance with the product manufacturers' instructions, including the correct use of appropriate cables. Installations are assessed for EMC only in case of complaint (of either excessive emission or inadequate immunity). -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: New EMC standards; now CISPR24/EN55024 query
I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B526@ORSMSX108) about 'New EMC standards; now CISPR24/EN55024 query', on Wed, 31 Oct 2001: Even then, changes in CISPR documents occur at glacial speed. This isn't always a bad thing, either. Things are changing, even in CISPR. And while deliberation may not always be a bad thing, a lack of immunity in an industrial computer must always be a bad thing, and very possibly a BAD THING! -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: EN 55022 limits
I read in !emc-pstc that Cook, Jack jack.c...@cax.usa.xerox.com wrote (in 966d119da042d21193780001fa8719c60605d...@caxmail.cax.es.xerox.com) about 'EN 55022 limits', on Wed, 31 Oct 2001: Are you interpreting the other reasons as meaning if one doesn't have a 10 m facility, then it's ok to test at 3 m? I'm a tiny bit skeptical that this was the intent. Or has this practice been accepted? I think so. 10 m facilities are very rare in some countries. -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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: EN 55022 limits
I read in !emc-pstc that Pettit, Ghery ghery.pet...@intel.com wrote (in D9223EB959A5D511A98F00508B68C20C0226B518@ORSMSX108) about 'EN 55022 limits', on Wed, 31 Oct 2001: The note in CISPR 22 that allows testing at alternate distances applies only to class B products. What is the justification for not allowing it for Class A? Is it assumed that Class A products might be larger? -- Regards, John Woodgate, OOO - Own Opinions Only. http://www.jmwa.demon.co.uk Eat mink and be dreary! --- 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.
