I've been performing in-house calibrations of LNA's, LISN's, CDN's, Current clamps and they have been accepted by the auditors. There is no restriction in terms of 17025 if you follow the requirements such as dedicated calibration instrumentation and MEASUREMENT UNCERTAINTY assessment. I admit my MU figure for calibration is larger than a calibration laboratory and it is accounted in EMC measurements. Again, how do you guarantee / justify what you are doing if you don't care about the MU.
I am strongly disagree with the I did it and it is correct attitude in EMC discipline. Maybe it explains the overall situation and measurement deviations between the laboratories OOO (Own opinions only) Best regards, Deniz Demirci National Technical Systems (NTS Canada) Phone: 403-568-6605 ext 244 fax: 403-568-6970 email:deniz.demi...@ntscorp.com web: http://www.ntscorp.com/about/locations From: emc-p...@ieee.org on behalf of Bob Richards Sent: Thu 8/12/2010 7:51 AM To: emc-p...@ieee.org Subject: Re: Calibration supplier for signal generator with pulse modulation --- On Thu, 8/12/10, Ken Javor <ken.ja...@emccompliance.com> wrote: And similarly, not because of MU but because of 17025 or perhaps ISO 9000, I've seen test equipment that could easily have been calibrated in house, such as current probes, LISNs and a 41 inch rod antenna have to be sent to the calibration lab. This is totally unproductive, except for the calibration lab. And I would argue further that it is detrimental to the discipline, because if you do your own calibration, you understand better how things work. This is a subject near to my heart. I've performed in-house calibrations of cables, LISNs, CDNs, current probes etc, and I agree 100% with what you said. Knowing the procedure helps to understand how things work and, just as important, gives a person the knowledge of how to perform quick verifications of a test setup in case there is ever any question as to the proper operation of that equipment. Every so often, a conversation comes up in the lab about whether we should do in-house calibrations. The issue is never about MU, cost or validity of data, it usually hinges around 17025 and what auditors will say. IMHO, shipping LISNs and/or CDNs to have calibrations performed by a cal lab is less reliable than in-house calibrations. This has little to do with the cal lab's ability, but from the possibility of damage during shipping. I've had CDNs come back with stuff rattling around inside (possibly chips off of ferrites?). If I can't perform an impedance verification in house, then what should I do to insure it is not damaged - send it back to the cal lab? Bob R. - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com> - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <emc-p...@ieee.org> All emc-pstc postings are archived and searchable on the web at http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <emcp...@socal.rr.com> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher <j.bac...@ieee.org> David Heald <dhe...@gmail.com>
