ISO INTERNATIONAL STANDARD 7066-2 First edition 1988-07-01 INTERNATIONALORGANIZATIONFORSTANDARDIZATION ORGANISATION INTERNATIONALE DE NORMALISATION ME>KAYHAPOAHAROPFAHM3ALMAOCTAHAAPTM3ALMW Assessment of uncertainty in the calibration and use of flow measurement devices - Part 2: Non-linear calibration relationships Evaluation de I'incertitude dans I'etalonnage et I'utilisation des appareils de mesure du debit Partie 2: Relations d'etalonnage non lineaires Referencenumber ISO 7066-2 : 1988 (E) Coovriaht Intemational Oraanization for Standardization ISO7066-2:1988 (E) Foreword Iso (the International Organization for Standardization) is a worldwide federation of national standards bodies (sO member bodies). The work of preparing International Standards is normally carried out through Iso technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- mental and non-governmental, in liaison with ISo, also take part in the work. iso collaborates closely with the International.Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulated to the member bodies for approval before their acceptance as International Standards by the ISo Council. They are approved in accordance with ISO procedures requiring at least 75 % approval by the member bodies voting. International Standard ISO 7066-2 was prepared by Technical Committee ISO/TC 30, Measurement of fluid flow in closed conduits, Users should note that all International Standards undergo revision from time to time and that any reference made herein to any other International Standard implies its latest edition, unless otherwise stated. ? International Organization for Standardization, 1988 Printed in Switzerland Coovriaht International Oraanization for Standardization ISO 7066-2:1988 (E) Contents Page Introduction Scope and field of application . 1 References Definitions - Symbolsand abbreviations 1 2 Curve fitting. 5.1 General 2 5.2 Computational methods 3 5.3Selecting the optimum degree of fit 3 6Uncertainty Annexes A Regression mothods 5 B Orthogonal polynomial curve fitting 9 c Computer program using orthogonal polynomials 11 D Examples. 17 E Finite-difference method . 27 im