During the initial period, the batching system was characterized by single loop regulation. At this time, the computer is used as a tool for digital calculation, or for digital statistics or digital analysis, and there is no physical connection between the computer and the batching device. The computer only acts as an "offline".
During the centralized development period, the batching system is realized by centralizing the display, operation and control of several control loops and all variables on a single computer. However, this also created a problem, that is, the vulnerability of concentration. A single computer controlled all the circuits and concentrated the danger. Once the computer malfunctioned, it caused a total paralysis.
With the continuous improvement of the decentralization of modern industrial control and the concentration of management, distributed or distributed batching control systems came into being. The distributed batching control system consists of a distributed instrument control system, which divides the control system into several independent local control systems to complete the automatic control tasks of the controlled production process. The emergence and development of microcomputers provide a material and technical basis for decentralized control. The distributed control system adopts standardized, modular and serial design. It is composed of process control level, control management level and production management level. It is a centralized display operation management with communication network as the link. The control is relatively decentralized and has flexible configuration. Multi-level computer network system structure with convenient configuration. It is produced by the mutual development and penetration of computer technology, signal processing technology, measurement control technology, communication network technology and human-machine interface technology. It is different from the decentralized instrument control system and the centralized computer control system. It is Absorbing the advantages of the two, a system engineering technology developed on the basis of them has strong vitality and significant advantages
