Required separation between item with 3V/m radiated immunity and Class A (industrial) emissions?
Hi Folks. At the moment I'm examining as a generic case, the potential for interference with Item A (tested to comply with 3V/m radiated immunity) caused by Item B (tested to comply with FCC or EN Class A [industrial] emissions). Using simple inverse distance ( E2 = E1 x d1/d2 ) extrapolation (assuming dominant interfering frequencies will be in the far field), I come up with a required separation distance of approximately 75cm to ensure the 3V/m immunity limit of Item A isn't exceeded by the 47dBuV/m emissions from Item B. Based on this, I'd expect then the risk for EMC problems should be relatively low provided: 1. A minimum separation of 1m was used between Items A B; 2. No direct interconnection of A to B via cables; 3. Use of a mains filter and/or separate power supply sources for A B; 4. The nature of Item B is such that no significant low (eg.power) frequency magnetic fields are emitted; Does anyone have any experience to suggest that the minimum separation of 1m under theses conditions would not be adequate? Thanks, Peter Poulos Design Engineer Foxboro Transportation (Invensys Rail Systems Australia) --- 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.
Standard for EM Immunity for cardiac pacemakers?
Can anyone point me in the direction of any standards that would cover the electromagnetic immunity requirements for cardiac pacemakers? The focus of my interest is for pacemakers that are likely to be found in Hong Kong or southern China. The closest I've found with my own hunting so far is IEC 60601-1-2 Medical electrical equipment - Part 1-2: General requirements for safety - Collateral standard: Electromagnetic compatibility - Requirements and tests but suspect there would be some more specific requirements for something so likely to cause a safety risk if it malfunctions. Thanks. --- 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: Transformer isolation (military)
Hi Dave. According to the documents on the DoD ASSIST-Quick Search web site, there are no longer any sections of MIL-T-27 that are active. They are all either marked inactive or cancelled. Most are available for viewing if you want to find out what tests the transformer was actually designed to pass. http://astimage.daps.dla.mil/quicksearch/ At 06:50 AM 29/03/2001, you wrote: Has anyone out there got any comments about the following: I have been involved with the import, into the U.K, of an item of off the shelf military equipment from the U.S.A. This avionics item operates from 3 phase 115v rms. I am told that the internal step down power transformer, which as far as I am concerned is required to provide double insulation primary to secondary, is only required to have 500v rms isolation, primary to secondary. This attribute, it is said, is compliant to MIL-T-27. There is always the perennial problem of matching military equipment characteristics to modern safety specifications, particularly for existing equipment, but 500v seems rather low, but then the MIL spec is current. Does anyone have any comments or advice about this. Dave Palmer --- 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: http://www.rcic.com/ click on Virtual Conference Hall,
IEC 61326 ammendment 2 - what does it cover?
Hi Folks. Been having hassles ordering a copy of ammendment 2 for IEC 61326-1 Was wondering if anyone can tell me the upshot of the changes. Regards, Peter Poulos --- 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: http://www.rcic.com/ click on Virtual Conference Hall,
Re: Safety of Add on components
Hi Brian. I'd agree with the gist of Oscar's comments. To paraphrase Scott Adams (creator of Dilbert) - everyone is an idiot for at least part of each day. I'd also like to add though, that even if the people you expect to have fitting the components are technically competent, I'd say there's still a pretty good chance that occasionally one of these people will act without thinking or slip and bump or touch something they shouldn't. So at the very least, I'd advise trying to ensure that not only after the assembly process, but also during the assembly process you take steps to protect them from any potential safety hazards. In some cases all you can reasonably do is provide adequate warnings (like turn the damn power off before you install the new component in the machine), but often a little thought about this sort of thing during the design can make components safer to install and use. Although you have to consider the commercial aspects of added costs, remember that the person who's fingers or eyes or life you save might turn out to be someone important to you. Regards, Pete. At 02:54 AM 3/11/2000, Brian Harlowe wrote: Hi Everybody A general question. Our company manufactures High tech Scientific Instruments. We also sell component parts for customers to fit to these instruments which we generally allow the users to fit and connect up. I would appreciate the groups comments on how safe we have to make this sort of item. Bearing in mind this is sold to customers with technical knowledge and in some cases electrical competence. Not members of the general public! We also supply a detailed set of instructions and in some cases we only provide setting up information on reciept of a declaration of competence As I say I would be interested in the groups comments on this both for Europe and North America Brian Harlowe Thermo V.G. Scientific Tel +44 (0)1342 327211 Fax +44 (0)1342 315074 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Re: Surge testing.
IEEE C62.41-1991 has some good background information on rates and severity of power surges - graphs for surge peak vs rate of occurrence etc. At 09:34 AM 20/10/2000, Cameron O'phee wrote: Hi all, I would like to know if anyone could point me to any articles or studies of real world mains born interference that substantiate the need to test equipment for immunity to these phenomena. I want to convince an engineer from another company that the standards my company has chosen to adopt are not excessive. Regards, Cameron O'Phee. EMC Safety Precompliance. Aristocrat Technologies Australia. Telephone : +61 2 9697 4420 Facsimile : +61 2 9663 1412 Mobile : 0418 464 016 --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
RE: Near Field Versus Far Field
Hi Don. Thanks for the example. Hearing about these kinds of experiences makes troubleshooting easier for everyone I think. Thanks to Chris Maxwell for his contribution too. It'd be great to hear more stories from the experience of some other members of the group. I think your approach was great for the problem you had, but wanted to say it doesn't always yield the quickest answer. To add to the examples: Most of the equipment we test has a large number of (mostly long) communication cable attachments. We had a recent experience where the equipment was over the limit due to emissions being conducted onto one such cable. Although with the cable attached the emissions from the cable were high, the actual emissions from the source in the near field were low (most of the noise was directly conducted onto the cable rather than radiated from the problem circuit board). Near field probing wouldn't have told us any quicker what the source was than the educated guessing + far-field measurement approach we took. In our case though, just from the frequency of the emission we already knew which circuit board was the culprit so it was just a matter of finding out what the coupling mechanism was to the cable. Under different circumstances though, I certainly agree that if you can use near field probes to home in on an unknown source, that would be likely to yield an answer quicker than trial and error. I guess I'm trying to say near field probing is useful, but doesn't always work. Because there can be such differences in the emissions measured in the near field as opposed to the far field it isn't always the best method. Regards, Pete. - Please note: The views, opinions and information expressed and/or contained herein do not necessarily reflect the opinions or views of Foxboro, the organisation/s through which this communication was transmitted nor any other third party, unless explicitly stated so. Peter Poulos (Hardware Design Engineer) Foxboro Australia At 12:16 AM 16/09/2000, umbdenst...@sensormatic.com wrote: Hello Joe, Consider the following -- in the far field (3 or 10 meters), a plane wave is monitored. In the near field, using either commercial or lab built near-field probes, either E field or H field emissions will be monitored separately. The E, H components will be isolated. The emission may be identified with a probe, but the effective radiator (culprit antenna) for that emission might be missed. The above is an answer to the question. If you would like a real life experience describing the difference, read the example that follows. On a recent product we had a band of frequencies of non-compliant emissions that were somewhat polarity sensitive. We observed a particular signature of the emission (modulation on a pulse) at 3 meters using a bilog antenna. Using a direct contact E field probe, the pulse frequency showed up at high levels around the processor and DSP chip, but not with the signature. We were able to find a trace of the corresponding polarity that was suspect and had a similar signature, and at a lower level than we found around the processor and DSP chip. Looking at the schematic, we identified a reasonable fix. But that only helped part of the profile. We then sniffed with a non-contact magnetic loop probe and found another viable culprit. The fix implemented brought the product into compliance with reasonable margin. Neither fix by itself brought the product into compliance. Both were necessary, required a minimum amount of components and contributed to rationale source suppression. We did not introduce balloon squeezing, i.e., beat down an emission at one frequency and see it pop up at another frequency. This kind of isolation is more effective than monitoring the far field emission, hypothesizing the culprit antenna while analyzing the schematic. We have done it both ways. The near field approach takes a little more time to set up but saves time in the long run. Or maybe we were just lucky! Best regards, Don -- From: marti...@appliedbiosystems.com[SMTP:marti...@appliedbiosystems.com] Reply To: marti...@appliedbiosystems.com Sent: Thursday, September 14, 2000 1:07 PM To: emc-p...@majordomo.ieee.org Subject: Near Field Versus Far Field I am having a difficult time answering the following question for a non-technical person. Hopefully, someone can put the answer into a language that a non-technical person can understand. We have a 400 MHz clock and are failing radiated emissions at 10 meters by 10 dB at 400 MHz. We bring the product back to our lab and start making modifications on the clock circuit and taking measurements with a near field probe. With these modifications and measuring with a near field probe, we realize a 10 dB reduction in emissions at 400 MHz. Why would we not see the same reduction
RE: Near Field Versus Far Field
Thanks Michael. I agree completely. Even though my comments probably didn't reflect it too well(hastily bashed out late on a Friday afternoon), changing one thing at a time is how I'd normally work on these problems. At 10:59 PM 15/09/2000, michael.sundst...@nokia.com wrote: I might add that the BEST way to do this is to only change one thing at a time, then retest. It's hard to tell what single change of the multiple changes attempted actually did the change. Michael Sundstrom Nokia Mobile Phones, PCC EMC Technician cube 4E : 390B phone: 972-374-1462 mobile: 817-917-5021 michael.sundst...@nokia.com amateur call: KB5UKT -Original Message- From: EXT Peter Poulos [mailto:pet...@foxboro.com.au] Sent: Friday, September 15, 2000 1:38 AM To: marti...@appliedbiosystems.com; emc-p...@majordomo.ieee.org Subject: Re: Near Field Versus Far Field Hi Joe. You asked for an explanation as to why the difference between the near and far field results. I think the replies so far have probably answered that question. I've tried here to give some help with the real problem of solving the excess emissions. From my own experience and discussions with colleagues, I've found you definitely need to do some (if not most) of the trouble-shooting while at the test site. Finding a problem then just returning to the lab to solve it usually leaves you with a lot of questions unanswered. That might not be much help this time but perhaps next time? The following is how I'd go about tackling the problem. I'm curious to see if there's anyone in the group who disagrees with my approach. As with any EMC problem, you've got to consider the source, the transmission medium and the victim. Obviously there's nothing you can change about the victim (the test antenna) but you should be able to narrow it down to work out the real source, and the means by which it is being radiated. For clues to the problem's cause to begin with I usually ask: (1) For the problem frequency, what's the most likely source? (2) For the problem frequency, what's the most likely source antenna? At 400MHz the wavelength is a bit under 1m (3x10^8 / 400x10^6 = 75cm) so any short cables (or at this frequency, maybe even long PCB track - like back-plane tracks?) that might make nice 1/2 wavelength or 1/4 wavelength dipole antennas would be the first I'd check out. Could also be a slot antenna effect in your enclosure - any seams or gaps in the box that are in this ball-park? Usually I'd try isolating the source by either disconnecting cables, turning off or unplugging cards, attenuating cable emissions with copious amounts of ferrite clamps etc and get the test engineer to do a spot check at the problem frequency as I tried eliminating each suspect. This is where the buckets of ferrite cable clamps, rolls of aluminium foil, shielding mesh and earthing straps come in to play. Here's where that near-field probe might come in handy too. This kind of troubleshooting though often requires a fairly intimate understanding of the way the equipment under test works so you can be confident about your assumptions and the conclusions you draw from the observed results. If the design engineer isn't actually at the test site, she/he should at least be accessible by phone to discuss the problems and make suggestions as to what to try. Using this technique, you can usually narrow it down fairly quickly to the source and antenna. If there's time, and its practical then I'd try some quick modifications to the problem circuit that's the source of the noise in order to get some reference of what changes cause what kind of reduction in the emission levels. Quite often though, you have to be aware that a change may solve the emission problem at the frequency you're working on, but result in the energy appearing elsewhere in the radiated spectrum causing the equipment to exceed the limit at some other frequency, especially if you've just modified the source antenna and not the signal causing the emission. Also note - although its difficult when you're rushing to get the problem fixed, it pays to make good records of what you change and what the results are - can help a lot later on. If you have the time at site to try a few different options (that are repeatable later), and get the highest 3 or 4 emission levels for each option at site, then if you can't find a solution you're happy with at the test site, it gives you a reference to work with back in the lab. For example, say that you found that: Design Change #1 resulted in 6dB reduction in the emission at 400MHz with other peaks (below the pass/fail limit) at 200MHz (3dB under), and 800MHz(8dB under) Design Change #2 resulted in 20dB reduction in the emission at 400MHz but caused the peak at 200MHz that went over the limit by 6dB with the peak at 800MHz reducing to 10dB under the limit. Design Change #3 resulted in 3dB reduction in the emission at 400MHz with other peaks (below the pass/fail limit) at 200MHz
Re: Near Field Versus Far Field
who owns a farm/ranch?) or perhaps the roof at work, to those measured at the test site. Use the antenna and analyser to measure the peaks with your equipment under test switched off first so you have an idea of what the ambient peaks are, then measure the emissions from the unmodified equipment, set up as close as practical to how it was at site. Although far from ideal, if you can see a decent correlation between what you measure and what was measured at site for the same equipment under test, then I'd have a lot more confidence in the results of this kind of measurement than for those taken in the near field. Although the results would only be ball-park, that's often all you need anyway. Given the expense of official OATS testing (unless your company happens to won its own site), I'd want to be pretty confident of a fix before booking in again. Hope that's of some help. Regards, Peter Poulos - Please note: The views, opinions and information expressed and/or contained herein do not necessarily reflect the opinions or views of Foxboro, the organisation/s through which this communication was transmitted nor any other third party, unless explicitly stated so. Peter Poulos (Hardware Design Engineer) Foxboro Australia At 03:07 AM 15/09/2000, marti...@appliedbiosystems.com wrote: I am having a difficult time answering the following question for a non-technical person. Hopefully, someone can put the answer into a language that a non-technical person can understand. We have a 400 MHz clock and are failing radiated emissions at 10 meters by 10 dB at 400 MHz. We bring the product back to our lab and start making modifications on the clock circuit and taking measurements with a near field probe. With these modifications and measuring with a near field probe, we realize a 10 dB reduction in emissions at 400 MHz. Why would we not see the same reduction when taking the product back to a 10 meter site? Your help is appreciated. Regards Joe Martin marti...@appliedbiosystems.com --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson:pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
Magnetic field immunity in the Arctic regions
Hi folks. Has anyone had experience with demonstrating immunity to magnetic fields that can be expected in the Arctic / north pole regions? I'm trying to find out what level of magnetic fields can be expected as a worse case in order to demonstrate immunity of some electronic equipment. Is anyone aware of any standards that would cover this? - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, jim_bac...@monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
EMC for automation control - Electricity utilities (UNIPEDE)
Hi. I've recently been shown a standard published by a European group called UNIPEDE titled Automation and Control Apparatus for Generating Stations and Substations - Electromagnetic Compatibility Immunity Requirements - Ref# 23005Ren9523. This standard generally adheres to the same requirements for immunity as the CE-mark standards, however for ESD it requires 8kV contact and 15kV air for HV substation environments. As is usually the case, there's no rationale provided as to why these levels where chosen (something that really annoys me about most standards). Does anyone have suggestions as to why the authors of the standard would expect worse ESD conditions in a substation than they seem to expect in an air conditioned, carpeted office? (equipment in environments other than HV substations only need meet 6kV contact, 8kV air according to this standard) - Please note: The views, opinions and information expressed and/or contained herein do not necessarily reflect the opinions or views of Foxboro, the organisation/s through which this communication was transmitted nor any other third party, unless explicitly stated so. Peter Poulos (Hardware Design Engineer) Foxboro Australia 42 McKechnie Drive, Eight Mile Plains, QLD, Australia 4113 Tel:+61 (07) 3340 2118 Fax: +61 (07) 3340 2100 E-mail:pet...@foxboro.com.au - This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to majord...@ieee.org with the single line: unsubscribe emc-pstc (without the quotes). For help, send mail to ed.pr...@cubic.com, j...@gwmail.monarch.com, ri...@sdd.hp.com, or roger.volgst...@compaq.com (the list administrators).
MIL-STD-461,462
Greetings. Does anyone know of an EMC test laboratory in Australia which has experience in testing to MIL-STD-461 and/or MIL-STD-462 (Emissions Susceptibility tests)? Sincerely, Peter Poulos = Peter Poulos Hardware Development Engineer Foxboro-LN (Australia) Ph: +61 7 3340 2118 E-mail: pet...@foxln.com.au
EN61010-1/IEC 664 Installation Category
Greetings folks. I'm in the process of working out what tests need to be performed on a particular product for compliance with EN61010-1. The item in question operates from a DC supply. For determining the test level required for impulse withstand, I need to determine which Installation Category (Overvoltage) Category is applicable. Unfortunately, the standard only provides AC supply voltages (phase-to-earth voltage) in its table for determination of the applicable category. The installation category selection is based on IEC 664. Is there anyone who has encountered this problem with EN61010-1 or IEC 664 who can offer advice? Thanks in advance, Peter Poulos Hardware Development Engineer Foxboro-LN (Australia) Ph: +61 7 3340 2118
Re: ITE approvals for Australia
Charles, For info on what's required for the C-Tick, I suggest you contact the SMA (Spectrum Management Agency ). They have a web site which may help (http://www.sma.gov.au) or you can email them at e...@sma.gov.au. Regards, Peter Poulos Hardware Development Engineer Foxboro-LN At 10:44 AM 3/26/97 -0700, you wrote: Does anyone know if IMMUNITY testing is required for ITE equipment for the C-Tick mark?
Re: ITE approvals for Australia
Charles, For info on what's required for the C-Tick, I suggest you contact the SMA (Spectrum Management Agency ). They have a web site which may help (http://www.sma.gov.au) or you can email them at e...@sma.gov.au. Regards, Peter Poulos Hardware Development Engineer Foxboro-LN At 10:44 AM 3/26/97 -0700, you wrote: Does anyone know if IMMUNITY testing is required for ITE equipment for the C-Tick mark? __ * . * * _--_|\ Peter Poulos * * / \ Foxboro-LN (Formerly LEEDS + NORTHRUP) * * \_,--._/Powerful Technology/Simple Solutions * *v 42 McKechnie Drive, Eight Mile Plains, QLD, Australia 4113 * * * * Tel:+61 (07) 3340 2118 Fax: +61 (07) 3340 2100 Internet:pet...@foxln.com.au * __
