RE: EMC Test Conditions
Bandele, Absolutely, if the situation/cost/timeline require it. Alternately, if the problem is minor, cheap and easy to I fix it and go away, even if I believe the requirement is wrong. Obviously, with organizations that have the legal authority to completely stop the process losing the argument pretty much dictates that you going to have decisions to make. You may have to re-evaluate the market to see if the money is there to proceed further, and if it is make the changes, if not drop the project. The only real long term solution to these types of problems are to work with and support standards making organizations to clarify or make corrections to the standards. A couple of examples: Years ago, when I was involved with monitors, the Nordic countries had requirements for the control of EM that the cost to build monitors from them meant that we didn't produce monitors for that part of the world. We actually, provided the systems with OEM monitors, and jacked up the price accordingly. (Marketing loves it when I use the terms like jacking up the price). I have had at least one safety agency try to hold me up with a requirement for seeing the emissions profile before giving me a safety mark. I pointed out that they had no authority to do so and they referenced various standards hoping that I wouldn't fully understand what was in them. I simply pressed them to show me the section in the standard which gave them such authority. It was quiet for awhile, then the engineer's boss called, and I repeated the arguments. It got quiet again while the went back to their world headquarters, and eventually when they couldn't find the legal or standards authority they capitulated. This isn't a matter of being pig-headed simply for the sake of being pig-headed, it was more of a matter of someone trying to add time to market by serializing my compliance process; complete EMC and then start safety. In order to keep the time to market as short as possible I believe the process must be parallel. The safety issues are investigated with the earliest prototype I can get my hands, and I begin the EMC process as soon as a system is ready for EMC tests. Eg. Safety agencies get may get wire wrap boards, and as soon as I get the re-worked boards I head off EMC certification, whether or not the safety is done. Yup, that can mean I have some issues to bring up with the safety agencies should I have to make modifications to the product that would affect them, but pragmatically that doesn't happen very often. I fear that a negative image is growing here. In my own defense I really don't spend the day trying to alter the course of the universe. I much prefer to work congenially along with others. They, like me, sometimes make mistakes or have to rely on standards that they can only interpret and sometimes they get it wrong, sometimes I get it wrong. But it would be remiss of me as to simply acquiesce when it imposes truly unnecessary expense and time, just to be a nice guy and not rock the boat. Gary -Original Message- From: Bandele Adepoju [mailto:badep...@jetstream.com] Sent: Tuesday, March 07, 2000 3:10 PM To: emc-p...@ieee.org Cc: 'Gary McInturff' Subject:RE: EMC Test Conditions Gary, This brings up an interesting observation, considering your point of view (and setting aside the matter of who is going to represent whom in court). Where do the TCBs, CABs, CBs fit into all this? It is my understanding that they interpret the rules, not just follow them. Do you insist on your position, contrary to theirs? Bandele Jetstream Communications, Inc. Los Gatos, CA -Original Message- From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf Of Gary McInturff Sent: Tuesday, March 07, 2000 11:59 AM To: 'Grasso, Charles (Chaz)'; Gary McInturff; 'lfresea...@aol.com'; emc-p...@ieee.org Subject: RE: EMC Test Conditions Charles, we probably don't disagree as much as you think. First of all let me clear up one point. I am not implying by any stretch of the imagination not to work with you test house. In 95% percent of the cases that will suit you very well, and they have in the past saved me some headaches. I have every confidence in the labs that I use (or I wouldn't use them) for this and other testing, I also have reasonable confidence in my knowledge and experience as well. The point I am trying to make is; when the situation isn't crystal clear, and there are large impediments
RE: EMC Test Conditions
Charles, we probably don't disagree as much as you think. First of all let me clear up one point. I am not implying by any stretch of the imagination not to work with you test house. In 95% percent of the cases that will suit you very well, and they have in the past saved me some headaches. I have every confidence in the labs that I use (or I wouldn't use them) for this and other testing, I also have reasonable confidence in my knowledge and experience as well. The point I am trying to make is; when the situation isn't crystal clear, and there are large impediments to getting it resolved, Then have to weight the lab input as well as my own. I take into consideration who pays the penalties for being right or wrong, and then make my decision on who to trust. If the test labs want to head into court for me and accept the full responsibility or if they want to pony up the $2,000,000 then I always listen to them. If not I probably will default to my opinion and act accordingly - again after listening carefully to what the lab says first and their justifications. If I have inadvertently offended some test labs I apologize. They do good work they are not infallible either, and if I have to pay the piper I will make the ultimate call. Thanks Gary -Original Message- From: Grasso, Charles (Chaz) [mailto:gra...@louisville.stortek.com] Sent: Tuesday, March 07, 2000 11:35 AM To: 'Gary McInturff'; 'lfresea...@aol.com'; emc-p...@ieee.org Subject:RE: EMC Test Conditions Gary - You make a compelling argument but I must disagree. I belive that BOTH the user and the testlab need to cooperate fully with good faith. The testlab is afterall the defacto expert in testing test standards, the user knows the product intimately (one hopes!) One or other cannot be fully responsible. BOTH together can produce a good test (again one hopes). -Original Message- From: Gary McInturff [mailto:gmcintu...@telect.com] Sent: Tuesday, March 07, 2000 12:05 PM To: 'lfresea...@aol.com'; emc-p...@ieee.org Subject: RE: EMC Test Conditions Derek, I think I have said this before, but the ultimate responsibility for compliance is yours not the test house. Their responsibility is to have equipment, staff, and procedures that allow them to make reliable and repeatable tests, in accordance with the test certification documents. In addition to that, as a customer service they can provide you with the latest in information or technical opinions. Sometimes these roles get confused and the test house assumes more responsibility than they really have, you certainly can understand why, they are trying to protect their reputation. But when in conflict use your own judgement. The test house can protect their accreditation and reputation by making whatever disclaimers they want about the test setup - but not how the test compares to the published limits. They can for example, state that while the test sample was measured to be under the required limits they are uncomfortable with the test set-up and they cannot assure the 90% upper confidence level with this arrangement, or something to that affect. In fact if they are following guide 25 for laboratories (part of their required documentation for certification) they actually have, but may not know it, a process for documenting customer and test discrepancies and problems. Given the number of possible set-ups and equipment operation and configuration there is ample room for reasonable and knowledgeable people to disagree. But when push comes to shove it is your responsibility to insure conformance, and you and your company will be the ones paying fines, removing or retrofitting equipment etc, not the test house. If you are convinced of your position and have listened carefully to what the test guys are telling you do as you see fit and let the test house make its comments in the test file. Then live with the consequences. Just an opinion Gary -Original Message- From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 7:27 AM To: emc-p
RE: EMC Test Conditions
Derek, With regard to the 3m cable limit. We also test to EN61326-1. In my eyes, the spirit of the standard is such that we can only take the exemption if the cable in question can be specified to a customer as less than 3m without restricting thier usage of your product. I have used this exemption for serial and parallel printer ports and put the 3m limit in the manual. I didn't feel guilty about this because there is an abundance of printer cables out there that are under 3m in length and fully shielded. In some cases we, tested these ports anyway and kept the 3m specification in our back pocket. If there was a failure that would be too costly to fix, then we would simply specify a cable less than 3m long to the customer.We also specify shielded cables for these ports. Paragraph 6.2 of the standard specifically exempts shielded cables and cables conductive cable trays or conduit from the conducted immunity requirements. However, we also have alarm leads on our products. These consisted of a set of terminal blocks to which a customer would terminate a wire pair. Given the customer installed nature of the wiring to the port, I felt that there was no way that we could limit the expected cable length to 3m. As a matter of fact, I considered them a long distance line. So, we went ahead with Conducted Immunity and Surge testing on these ports. With these ports, we rigged up a dummy cable 3m long. While it is very important to consider which ports to test; once you do decide to test a port, I don't think that the length of cable to use during the test is too important. Most labs will coil the wire into a bundle about two feet long anyway. (This keeps their results more repeatable.) I hope that I have helped you. Chris Maxwell -Original Message- From: lfresea...@aol.com [SMTP:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 10:27 AM To: emc-p...@ieee.org Subject: EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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
RE: EMC Test Conditions
Gary - You make a compelling argument but I must disagree. I belive that BOTH the user and the testlab need to cooperate fully with good faith. The testlab is afterall the defacto expert in testing test standards, the user knows the product intimately (one hopes!) One or other cannot be fully responsible. BOTH together can produce a good test (again one hopes). -Original Message- From: Gary McInturff [mailto:gmcintu...@telect.com] Sent: Tuesday, March 07, 2000 12:05 PM To: 'lfresea...@aol.com'; emc-p...@ieee.org Subject: RE: EMC Test Conditions Derek, I think I have said this before, but the ultimate responsibility for compliance is yours not the test house. Their responsibility is to have equipment, staff, and procedures that allow them to make reliable and repeatable tests, in accordance with the test certification documents. In addition to that, as a customer service they can provide you with the latest in information or technical opinions. Sometimes these roles get confused and the test house assumes more responsibility than they really have, you certainly can understand why, they are trying to protect their reputation. But when in conflict use your own judgement. The test house can protect their accreditation and reputation by making whatever disclaimers they want about the test setup - but not how the test compares to the published limits. They can for example, state that while the test sample was measured to be under the required limits they are uncomfortable with the test set-up and they cannot assure the 90% upper confidence level with this arrangement, or something to that affect. In fact if they are following guide 25 for laboratories (part of their required documentation for certification) they actually have, but may not know it, a process for documenting customer and test discrepancies and problems. Given the number of possible set-ups and equipment operation and configuration there is ample room for reasonable and knowledgeable people to disagree. But when push comes to shove it is your responsibility to insure conformance, and you and your company will be the ones paying fines, removing or retrofitting equipment etc, not the test house. If you are convinced of your position and have listened carefully to what the test guys are telling you do as you see fit and let the test house make its comments in the test file. Then live with the consequences. Just an opinion Gary -Original Message- From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 7:27 AM To: emc-p...@ieee.org Subject:EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables
RE: EMC Test Conditions
Interesting problems Derek.. Some comments: 1. Testing the device on a table. I'm not sure it is a stupid thing to do. As I see it this is a similar problem to rack qualifications. If the EUT does NOT require the metal support for any EMC performance (shielding/filter grounding) then testing and passing on a non- conductive support would be OK ...and look over here is a convenient table to put the equipment on. 2. On the other hand... If you are concerned that the metal support will detrimentally change the emissions profile - then you will need the actual structure and not a facsimile. (The table seems attractive to me..) 3. I agree with your concerns on the spec. To be so severly limited to floor/table top is also a concern of mine. 4. On your second concern. This is an issue I feel strongly about. There is a tendency to replace good judgement with letter of the law thinking. In this case I agree with Ed N. I guess the right thing is to look in the documentation to be delivered to the customer. If the lab still does not insist on the lab - find another lab!! -Original Message- From: John Juhasz [mailto:jjuh...@fiberoptions.com] Sent: Tuesday, March 07, 2000 11:52 AM To: 'lfresea...@aol.com'; emc-p...@ieee.org Subject: RE: EMC Test Conditions I agree with Derek that simulation of 'actual use'/'actual installation' of the EUT to the best of your ability is clearly the best way to test the equipment. Anything short of that isn't clearly representative. You note that It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. As long as the EUT is mounted to your smaller metal structure (1 cubic meter) to simulate the installation), what concerns do have with regard to the height at which it is tested? Is the product be normally at floor level? Or can it be mounted at any height? If it's normally mounted at floor level (and specified in the 'installation manual',if you have one), I would indeed fight it. Regarding your item #2, I am in agreement as well. If there is any question as to the product's compliance by an authority, having gone the 'straight narrow', and having it documented in the report is better than having less testing done because of the length of the cables. If I were the authority, THAT would be the product I would pull-in for verification of the test results. John Juhasz Fiber Options Bohemia, NY -Original Message- From: lfresea...@aol.com [ mailto:lfresea...@aol.com mailto:lfresea...@aol.com ] Sent: Tuesday, March 07, 2000 10:27 AM To: emc-p...@ieee.org Subject: EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment
RE: EMC Test Conditions
Derek, I would like to add to Scott's comment. You are probably not going to experience any benefits from the large metallic structure. If anything, it will act as an antenna, increasing your radiated emissions and decreasing your immunity. Your concerns regarding installation are valid and you may want to do on-site testing to determine the real world RF signature. Good Luck, Dave Spencer Oresis Communications -Original Message- From: Lacey,Scott [mailto:sla...@foxboro.com] Sent: Tuesday, March 07, 2000 8:17 AM To: 'lfresea...@aol.com' Cc: 'emc-p...@ieee.org' Subject: RE: EMC Test Conditions Derek, The points you make are extremely valid. Product testing should not be merely a paper chase, with a certificate as the only goal. I agree that if your product always gets bolted to a large metal structure, it should be tested in a simulated condition. However, and I am guessing here, if the structure is outdoors and painted, ground bonding through the structure may be poor in an actual installation. I guess it depends on what you are trying to accomplish. If the product will not pass without the metal structure, I would be highly skeptical of results obtained by the simulation. If, on the other hand, you are trying to simulate the worst case, I say press your case with the test lab. It has been my experience that problems experienced in testing, especially immunity, ALWAYS show up sooner or later in the field. That is why we try to bias tests towards failure. Scott Lacey -Original Message- From: lfresea...@aol.com [SMTP:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 10:27 AM To: emc-p...@ieee.org Subject:EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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
RE: EMC Test Conditions
Derek, I think I have said this before, but the ultimate responsibility for compliance is yours not the test house. Their responsibility is to have equipment, staff, and procedures that allow them to make reliable and repeatable tests, in accordance with the test certification documents. In addition to that, as a customer service they can provide you with the latest in information or technical opinions. Sometimes these roles get confused and the test house assumes more responsibility than they really have, you certainly can understand why, they are trying to protect their reputation. But when in conflict use your own judgement. The test house can protect their accreditation and reputation by making whatever disclaimers they want about the test setup - but not how the test compares to the published limits. They can for example, state that while the test sample was measured to be under the required limits they are uncomfortable with the test set-up and they cannot assure the 90% upper confidence level with this arrangement, or something to that affect. In fact if they are following guide 25 for laboratories (part of their required documentation for certification) they actually have, but may not know it, a process for documenting customer and test discrepancies and problems. Given the number of possible set-ups and equipment operation and configuration there is ample room for reasonable and knowledgeable people to disagree. But when push comes to shove it is your responsibility to insure conformance, and you and your company will be the ones paying fines, removing or retrofitting equipment etc, not the test house. If you are convinced of your position and have listened carefully to what the test guys are telling you do as you see fit and let the test house make its comments in the test file. Then live with the consequences. Just an opinion Gary -Original Message- From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 7:27 AM To: emc-p...@ieee.org Subject:EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC
RE: EMC Test Conditions
I agree with Derek that simulation of 'actual use'/'actual installation' of the EUT to the best of your ability is clearly the best way to test the equipment. Anything short of that isn't clearly representative. You note that It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. As long as the EUT is mounted to your smaller metal structure (1 cubic meter) to simulate the installation), what concerns do have with regard to the height at which it is tested? Is the product be normally at floor level? Or can it be mounted at any height? If it's normally mounted at floor level (and specified in the 'installation manual',if you have one), I would indeed fight it. Regarding your item #2, I am in agreement as well. If there is any question as to the product's compliance by an authority, having gone the 'straight narrow', and having it documented in the report is better than having less testing done because of the length of the cables. If I were the authority, THAT would be the product I would pull-in for verification of the test results. John Juhasz Fiber Options Bohemia, NY -Original Message- From: lfresea...@aol.com [mailto:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 10:27 AM To: emc-p...@ieee.org Subject: EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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: EMC Test Conditions
Derek, I run into the less than x feet issue all the time with my customers. They purposely make their cable just under this length to get out of testing for certain requirements. We tell them that is not the intent of the requirement, but that it only applies to lengths of cables that are specified to be such a length in their manual or literature and that it does not apply to the cable that is brought in with the EUT at the time of testing. Ed Nakauchi Director of EMC Technical Services Garwood Laboratories. inc. -Original Message- From: lfresea...@aol.com lfresea...@aol.com To: emc-p...@ieee.org emc-p...@ieee.org List-Post: emc-pstc@listserv.ieee.org Date: Tuesday, March 07, 2000 9:44 AM Subject: EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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: EMC Test Conditions
Derek, Someone once said, Customer is always right. You are the customer. I would find another lab. As long as your customers (people who buy your equipment and the people who enforce thr rules) are happy... From the logic you presented, I don't see how you would have a problem presenting your case. As far as making a change in the rules, good luck. My opinion only (maybe that of others out there too). Eric Petitpierre Pulsecom Herndon, VA eric.petitpie...@pulse.com __ Reply Separator _ Subject: EMC Test Conditions Author: lfresea...@aol.com at smtp List-Post: emc-pstc@listserv.ieee.org Date:3/7/00 10:27 AM Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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: EMC Test Conditions
Would it be appropriate to apply the TCF approach (EMC Direcitve definition) for your compliance statement? Exerpted from Article 10: 2. In the case of apparatus for which the manufacturer has not applied, or has applied only in part, the standards referred to in Article 7 (1) or failing such standards, the manufacturer or his authorized representative established within the Community shall hold at the disposal of the relevant competent authorities, as soon as the apparatus is placed on the market, a technical construction file. This file shall describe the apparatus, set out the procedures used to ensure conformity of the apparatus with the protection requirements referred to in Article 4 and include a technical report or certificate, one or other obtained from a competent body. Could you claim in your TCF that the emissions test was done with a simulated system, and include those results? On Tue, 7 Mar 2000 10:27:29 EST, lfresea...@aol.com wrote: the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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: EMC Test Conditions
Derek, The points you make are extremely valid. Product testing should not be merely a paper chase, with a certificate as the only goal. I agree that if your product always gets bolted to a large metal structure, it should be tested in a simulated condition. However, and I am guessing here, if the structure is outdoors and painted, ground bonding through the structure may be poor in an actual installation. I guess it depends on what you are trying to accomplish. If the product will not pass without the metal structure, I would be highly skeptical of results obtained by the simulation. If, on the other hand, you are trying to simulate the worst case, I say press your case with the test lab. It has been my experience that problems experienced in testing, especially immunity, ALWAYS show up sooner or later in the field. That is why we try to bias tests towards failure. Scott Lacey -Original Message- From: lfresea...@aol.com [SMTP:lfresea...@aol.com] Sent: Tuesday, March 07, 2000 10:27 AM To: emc-p...@ieee.org Subject:EMC Test Conditions Folks, the testing of a product at a MAJOR Compliance lab has me concerned. I have two main concerns, they are: 1) The test item is designed to be bolted to a large metallic structure which cannot be part of my set-up, it costs way to much ( $2,000,000 each ). So I have a fixture, which mounts all the components as they would be mounted, using wiring as it would be wired etc. etc. etc. Because this fixture is only about a cubic metre, the lab is telling me I should test as table top equipment. I don't think this is correct. IMHP, table top equipment is meant to be EUTs like PC, printers, coffee makers, TVs etc. In most cases, the location in which they reside has very little metal in the proximity. OTOH, control systems like ours, are almost always fastened to metal objects. It is important to have this metal, or a simulation of it present, because I've found that otherwise, there is little correlation to the final installation. I also feel strongly that lifting this metal structure 80 cm off the ground plane is a stupid thing to do. So, my opinion is that there needs to be a third testing consideration added to table top and floor mounted equipment, that of simulated installation testing. OK, so this would require additional work. But if this is not considered, then results from all these system will vary dramatically. We worry at great length about the setup for table top equipment, and floor equipment. But if systems don't fit in this category, it's open season! 2) Since my device can be installed almost anywhere, it is supplied with a 3 foot length of flying lead. The intent is for final customers to extend this cable as needed. Here the lab tells me I'm OK testing with just 3 feet of lead My product standard is EN 61326, which allows me if my cables are under 10' in length, to blow away FTB and CI testing. This is ludicrous! I know now how some of my competitors can claim EMC compliance when they fail in my lab. I feel very strongly about issue 1, enough that I would offer to draft guidelines to present to whoever makes the rules. On issue 2, there has to be some education, at the moment the playing field is not level. I do not want to play the same games as others, because I feel the EMC protection we incorporate is really needed. Anyone got any constructive comments? Derek Walton --- 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
