The industrial control system is the requirement of large data volume and high speed transmission such as image and voice signals, which has spawned the combination of Ethernet and control network that is popular in the commercial field. This wave of industrial control system networking will be such as embedded technology, multi-standard industrial control network interconnection, wireless technology and other popular technologies into the integration, thus expanding the development space in the field of industrial control, bringing new development opportunities.

With the development of computer technology, communication technology and control technology, the traditional control field is undergoing an unprecedented change and has begun to develop in the direction of networking.
The structure of the control system from the initial CCS(computer centralized control system), to the second generation of DCS(decentralized control system), to the now popular FCS(fieldbus control system).


Computer and network technology are closely related to the development of control systems. In the early 1960s, there appeared a control system that completely replaced analog control by computers, known as DirectDigitalControl (DDC). In the mid-1970s, with the emergence of microprocessors, computer control systems entered a new Period of rapid development, in 1975 the world's first set of microprocessor based distributed computer control system, it takes more than one microprocessor decentralized control together, and through the data communication network to realize centralized management, known as distributed control system (DistributedControlSystem, DCS).
After entering the 1980s, people use the microprocessor and some peripheral circuits to form a digital instrument to replace the analog instrument, this DDC control mode improves the control accuracy and control flexibility of the system, and in the multi-loop circuit sampling and control has the performance and price ratio that the traditional analog instrument can not match.
In the mid and late 1980s, with the increasing complexity of industrial systems and the further increase of control circuits, a single DDC control system can no longer meet the on-site production control requirements and production management requirements, while the performance and price ratio of small and medium-sized computers and microcomputers has been greatly improved. Therefore, the layered control system, which is composed of small and medium-sized computers and microcomputers, has been widely used.
After entering the 1990s, due to the rapid development of computer network technology, DCS system has been further developed, improve the reliability and maintainability of the system, DCS still occupies a dominant position in today's industrial control field, but DCS does not have open, complex wiring, high cost, there are great difficulties in the integration of different manufacturers' products.
Since the late 1980s, due to the development of large-scale integrated circuits, many sensors, actuators, drivers and other field equipment intelligent, people began to seek to use a communication cable to connect the field equipment with a unified communication protocol communication interface, the transmission of the equipment layer is no longer I/O(4 ~ 20mA/24VDC) signals, but digital letters This is the fieldbus. Because it solves the reliability and openness of network control system, fieldbus technology has gradually become the development trend of computer control system. Since then, some developed industrial countries and multinational industrial companies have launched their own fieldbus standards and related products, forming a herd of competitors.