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 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 ------------------------------------------- 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
