Automatic control systems are divided into two categories based on the different objects they control. A type of motion control system (also known as transmission control system) that requires electric motor drive to achieve motion properties, and the working process of the motion control system is called motion control; Another type of control object is the quantity in industrial production processes such as temperature, pressure, flow rate, material, composition, liquid level, and acidity/alkalinity, such as the production control of chemical products in distillation towers and the control of steam temperature in boilers. The automatic control system that controls such objects is called a process control system, and the working process of the process control system is called process control.
Generally, process control often involves the flow of objects and energy. By controlling the size of the flow of materials and energy, the requirements of process control objectives can be achieved. The executing element of motion control is the electric motor, and the executing element of process control is the regulating valve. Both motion control and process control are applicable to the same automatic control theory.
However, due to the different characteristics of the controlled objects, the two types of control systems also exhibit different response characteristics. For example, the adjustment time of the motion control system is short and the response speed is fast; However, process control systems often contain large inertia components, large delay components, etc., with long adjustment times and slow response speeds. There may be certain differences when applying control theory to solve specific control problems. In these two categories of control systems, control systems can be further classified based on the specific requirements of the control object, the characteristics of the input signal, whether the signal transmission process is continuous, whether the parameters are time-varying, and whether the system contains nonlinear components.