Accurate measurements play a vital role at each stage in development and production of quality product. The effectiveness of quality control steps depends directly on the accuracy and confidence with which the test & measuring instruments (TMI) can yield test results. Thus systematic and periodic checking of Test & measuring Instruments is very essential for reliable measurements. The process of periodic checking of TMI by comparison with another instrument of better accuracy is termed as Calibration.
Further for worldwide exchange of goods, products & technology and interchangeability of components & parts, it is essential that measurement represent the same quantity everywhere. This is possible only when the measurements have a common reference base, which is internationally accepted. This common reference base is the SI unit of measurement. Standard is the physical realization of the unit of measurement. The process of making sure that our measurement stem from a common reference base is termed as Traceability. Periodic calibration of TMI provides the most vital link between international standards of measurement and the day-to-day test & measurement data through the medium of National measurement standards held by the National standards laboratory.