Industrial instruments can automatically perform measurement, recording, and control tasks without human intervention. Furthermore, they enable long-distance information transmission and data processing.
Although industrial instruments are diverse, they are all based on the principle of balance, including force balance, torque balance, and electrical balance. The sensing part of the instrument—the sensor—takes the measured parameter (such as temperature, pressure, flow rate, etc.), which is then converted by the transmitter into amplifiable quantity (such as voltage, current, and mechanical quantity), and further amplified. Part of the amplified value is transmitted to the display unit, and the other part is compared with the measured value through the feedback unit to achieve balance.
There are many types of industrial instruments. According to the parameters of the production process being measured, they can be classified as temperature measuring instruments, pressure measuring instruments, flow measuring instruments, level measuring instruments, mechanical quantity measuring instruments, process analysis instruments, etc. Industrial instruments can also be classified according to their function in the industrial production process, such as detection instruments, display instruments, and control instruments.
Measurement instruments are mainly used to measure parameters in industrial production processes, such as temperature, pressure, flow rate, level, and mechanical quantities. Sometimes they also have recording and regulation functions. Display instruments are instruments that display the output signals of measurement instruments for observation. They are used in conjunction with measurement instruments, transmitters, and sensors. According to different display methods, they are divided into analog display instruments, digital display instruments, and character image display instruments. Regulation instruments, also known as regulators, are used to compare the measured parameters in the production process with the set parameters, and then send regulation signals to the actuators according to certain regulation rules.
Control instruments are classified into intermittent controllers and continuous controllers according to their control method; into base-type, unit-combination type, and assembly type according to their structural form; and into self-powered, electric, pneumatic, and hydraulic type according to their working energy source and medium. Some control instruments also have detection and display components.
