The purpose of a process plant is to convert raw material, energy, manpower and capital into end products. In some cases the quality of the product can be verified by doing necessary measurements of the final product, but in many cases the quality cannot be verified only by measurements of the final product. The only way to assure the quality of the end product is to perform measurements during the process. Typical examples are processes that require certain conditions during the process, such as temperature treatments during the process of the product.
Performing calibrations consumes time and money, and performing too many calibrations is a waste of resources, time and money.