What is DCS? Basic knowledge of DCS - Solutions - Huaqiang Electronic Network

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Dcs, the so-called distributed control system, or distributed system in some materials, is a new type of computer control system compared to centralized control systems. It is developed on the basis of centralized control systems. Evolved. In terms of system functions, DCS and centralized control systems have little difference, but the implementation of system functions is completely different.
First, the backbone of DCS - the system network, which is the foundation and core of DCS. By: Introduction to Distributed Control System (DCS)
DCS, the so-called distributed control system, or distributed system in some materials, is a new type of computer control system compared to centralized control systems. It is developed on the basis of centralized control systems. Evolved. In terms of system functions, DCS and centralized control systems have little difference, but the implementation of system functions is completely different.
First, the backbone of DCS - the system network, which is the foundation and core of DCS. Since the network plays a decisive role in the real-time, reliability and scalability of the entire DCS system, all manufacturers have carefully designed this aspect. For a system network of DCS, it must meet the requirements of real-time performance, that is, complete the transmission of information within a certain time limit. The time limit of "determination" mentioned here means that in any case, information transmission can be completed within this time limit, and this time limit is determined according to the real-time requirements of the controlled process. Therefore, the measure of system network performance is not the rate of the network, which is commonly referred to as the number of bits per second (bps), but the real-time nature of the system network, that is, how long the required information can be transmitted. . The system network must also be very reliable, and network communication can't be interrupted under any circumstances. Therefore, DCS of most manufacturers adopts a dual bus, ring or double star network topology. In order to meet the requirements of system scalability, the maximum number of nodes that can be accessed on the system network should be several times larger than the number of nodes actually used. In this way, on the one hand, new nodes can be added at any time, and on the other hand, the system network can be operated in a light communication load state to ensure real-time and reliability of the system. During the actual operation of the system, the Internet access and the offline network of each node may occur at any time, especially the operator station. In this way, network reconfiguration will be performed frequently, and such operation must not affect the normal operation of the system. Therefore, the system The network should have strong online network reconfiguration capabilities.
Second, it is a network node that is fully capable of handling field I/O and implementing Direct Digital Control (DOS). In general, a set of DCS should set up an on-site I/O control station to share the I/O and control functions of the entire system. In this way, the failure of the entire system due to failure of one site can be avoided, the reliability of the system can be improved, and the data collection and control functions can be shared by each site, which is beneficial to improving the performance of the entire system. The operator station of the DCS is a network node that handles all the functions of the human-machine interface (hmi-Human Machine Interface or operator interface) associated with the operation.
The system network is the engineering station of DCS. It is the network node for offline configuration, configuration work and online system supervision, control and maintenance of DCS. Its main function is to provide tool software for configuring and configuring DCS. That is, the configuration software), and monitor the operation status of each node on the DCS network in real time when the DCS is running online, so that the system engineer can adjust the system configuration and some system parameter settings in time through the engineering station, so that the DCS is always at the best. Under the working condition. Unlike centralized control systems, all DCS require a system configuration function. It can be said that a system without a system configuration function cannot be called a DCS.
Since its inception in 1975, DCS has experienced more than 20 years of development. In the past two decades, DCS has not undergone major changes in the system architecture, but its functions and performance have been greatly improved through continuous development and improvement. In general, DCS is moving toward a more open, more standardized, and more product-oriented direction.
As a computer control system in the field of production process automation, the traditional DCS is only a narrow concept. If you think that DCS is just an automated system of the production process, it will lead to erroneous conclusions, because the meaning of the current computer control system has been greatly expanded, it not only includes the various content contained in the past DCS, but also goes down to the Every measuring equipment and executing agency on the site has been developed to the production management and all aspects of business management. The traditional DCS now only refers to the automation of the production process control part, and the concept of the industrial automation system should be positioned to the enterprise comprehensive solution, that is, the level of the total solution. Only by asking questions and solving problems from this point of view can computer automation really play its due role.
After entering the 1990s, computer technology has advanced by leaps and bounds, and more new technologies have been applied to DCS. Plc is an electronic device developed for sequential logic control that is primarily used to replace inflexible and cumbersome relay logic. Fieldbus technology has developed so rapidly since the mid-1990s that some people have predicted that fieldbus-based FCS will replace DCS as the protagonist of control systems.