Sensor and Measurement
In addressing measurement problems, it is often seful to have a conceptual model of the measurement process. This chapter presents some of the fundamental concepts of measurement in the context of a simple generalized instrument model.
In abstract terms, an instrument is a device that transforms a physical variable of interest (the measurand ) into a form that is suitable for recording (the measurement ). In order for the measurement to have broad and consistent meaning, it is common to employ a standard system of units by which the measurement from one instrument can be compared with the measurement of another.
An example of a basic instrument is a ruler. In this case the measurand is the length of some object
and the measurement is the number of units (meters, inches, etc.) that represent the length.