1. Industrial control system refers to an automatic control system composed of computers and industrial process control elements, which consists of controllers, sensors, transmitters, actuators and input/output interfaces. These components are connected through industrial communication lines according to a certain communication protocol, forming an industrial manufacturing or processing system with automatic control capability.
2. According to "People's Republic of China (PRC) * * * Information Security Level Protection Industrial Control System Standard" and "National Security Industry Standard", the general hierarchical model of industrial enterprise control system can be divided into five logical layers from top to bottom according to different functions, which are enterprise resource layer, production management layer, process monitoring layer, field control layer and field equipment layer in turn. According to different hierarchical structure, each level plays different functions in industrial control system.
Second, the industrial control network
At present, there is no standard definition of industrial control network. Industrial control network is the network part of industrial control system, which is a communication network that organizes all production processes and automatic control systems in the factory through various communication devices.
2. The industrial control network consists of several "network nodes", which refer to measurement and control instruments with corresponding digital communication capabilities scattered in various production sites. It adopts standardized and open communication protocol, and takes the field bus as the link of communication connection, so that the field control devices can communicate with each other and jointly complete the corresponding production tasks.
3. Realizing measurement monitoring is the basic task of industrial control network, so industrial control network emphasizes the integrity, reliability and real-time of data transmission, which requires industrial control network to provide corresponding real-time communication functions.
4. From the development process, the industrial control network has evolved from the traditional control network to the field bus, and then to the wireless network and industrial Ethernet which are widely studied at present.
Three. Industrial control system and industrial control network
1. Industrial control system includes industrial control network and all industrial production equipment, while industrial control network only pays attention to the elements that constitute communication network in industrial control system, including communication nodes (including host and controller), communication network (including fieldbus, Ethernet and various wireless communication networks) and communication protocols (including Modbus and Profibus).
2. Many enterprises have misunderstandings about the security of industrial control networks: they think that industrial control networks are not directly connected with the Internet, and intruders cannot attack industrial control systems through industrial control networks. In fact, the control networks of many enterprises are "open" and there is no effective isolation between systems. In addition, hackers and malware using the latest technology can even effectively invade physically isolated networks.
Different from the traditional production safety, the network safety of industrial control system is to prevent and resist attackers from artificially creating production accidents, damages or casualties through malicious acts. It can be said that without the network security of industrial control system, there is no production security of industrial control system. Only by ensuring that the system does not suffer from malicious attacks and destruction can the safety of the production process be effectively guaranteed. Although the network security of industrial control is also caused by various malicious attacks, the network security of industrial control is very different from the traditional IT system.