Instrumentation is an instrument or equipment used to detect, measure, observe and calculate various physical quantities, material components and physical parameters. Vacuum leak detector, pressure gauge, length measuring instrument, microscope and multiplier are all instruments.

Broadly speaking, instruments can also have the functions of automatic control, alarm, signal transmission and data processing, for example, pneumatic regulating instruments, electric regulating instruments and distributed instrument control systems used in automatic control of industrial production processes also belong to instruments.

Instruments can improve, expand or supplement people's functions. People use sensory organs to see, hear, taste and touch external things, and instruments such as microscope, telescope, sound level meter, acidity meter, pyrometer and vacuum centrifugal concentrator can improve and expand these functions; In addition, some instruments and meters, such as magnetometer and ray counter, can feel and measure physical quantities that can't be felt by human sensory organs, and some instruments and meters can record, calculate and count beyond human ability, such as high-speed cameras and computers.

Instruments are important "tools" for the development of science and technology. Wang Daheng, a famous scientist, pointed out that "machines are tools for transforming the world, and instruments are tools for understanding the world". Instruments are multipliers of industrial production, pioneers of scientific research, military combat effectiveness and materialized judges of modern social activities. It goes without saying that instruments play a very important role in promoting the development of science and technology and national economy in today's era.