Metrology the Science of measurements
Metrology and calibration can be traceable back many millennia. Some of the early examples are mentioned in the texts of Manusmrithi in India and in the ancient Egyptian literatures. Metrology has undergone several industrial revolutions leading to the complexities of modern day microprocessor-controlled measurements. Today’s technological evolution has made it possible to measure parameters deemed impossible only a few years ago. Improvements in accuracy, tighter control, and waste reduction have also been achieved.
This book is specifically written as an introduction to modern day metrology and calibration for the benefit of technical, vocational, or degree students, and as a reference manual for managers, engineers, and technicians working in the field of calibration. It is anticipated that the prospective student will have a basic understanding of mathematics, and physics. This course should adequately prepare a prospective technician, or serve as an introduction for a prospective engineer wishing to get a solid basic understanding of metrology and calibration. Metrology involves a wide range of technologies and sciences, and they are used in an unprecedented number of applications.
Metrology is defined by the International Bureau of Weights and Measures (BIPM) as “the science of measurement, including both experimental and theoretical determinations at any level of uncertainty in any field of science and technology. Core concept in metrology is traceability, defined as “the property of the result of a measurement or the value of a standard whereby it can be related to stated references, usually national or international standards, through an unbroken chain of comparisons, all having stated uncertainties.” The level of traceability establishes the level of comparability of the measurement: whether the result of a measurement can be compared to the previous one, a measurement result a year ago, or to the result of a measurement performed anywhere else in the world.
Traceability is most often obtained by calibration, establishing the relation between the indication of a measuring instrument and the value of a measurement standard. These standards are usually coordinated by national metrological institutes: National Physical Laboratory (NPL) New Delhi, etc. Traceability, accuracy, precision, evaluation of measurement uncertainty are critical features of a calibration management system.