Why is it "impossible, or at least very difficult" to determine auto calibrator uncertainty ?
luck, Brian > -----Original Message----- > From: [email protected] [mailto:[email protected]]On Behalf > Of Barker, > Neil > Sent: Wednesday, October 31, 2007 2:35 AM > To: 'Gordon,Ian'; 'IEEE EMC & SAFETY PSTC' > Subject: RE: UKAS v standard calibration > > Ian, > > An accredited laboratory will be operating to ISO 17025 and > will provide a > statement uncertainty of measurement for any item that they > calibrate. This > is essential to have if you want to be able to make a statement of > uncertainty of measurement for any tests that you perform with that > equipment. Also, the calibration methods for an accredited > calibration will > generally have a shorter line of traceability to national > standards. In many > countries calibration that is not accredited is simply not > recognised. > > I think the UK is unusual in there being a large segment of > calibration > providers who operate to standards, and can prove a line of > traceability, > but are not operating strictly to ISO 17025; more likely > operating to ISO > 9001 + ISO 10012. > UKAS calibration is often more costly than a non-accredited > calibration > because it is impossible, or at least very difficult, to > calculate the > measurement uncertainty for automatic calibrators such as > are used routinely > for instruments such as oscilloscopes or multimeters. > > Best regards > > Neil R. Barker CEng MIET HonFSEE MIEEE > Manager > Quality Engineering > e2v technologies (uk) ltd > 106 Waterhouse Lane > Chelmsford > Essex CM1 2QU > UK == INSERT LOG REF 0xbc90a == - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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 [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc ______________________________________________________________________ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email ______________________________________________________________________
