DCS system

System introduction

DCS is the short for Distributed Control System (Distributed Control System), and it is commonly called distributed control system in China. It is a multilevel Computer system composed of process Control level and process monitoring level with Communication network as the link, integrating computer (Computer), communication (Communication), display (CRT) and control (Control) etc. The basic idea is decentralized control, centralized operation, hierarchical management, flexible configuration and convenient configuration.

The main technical characteristics of the system are summarized

1.The system mainly consists of field control station (I/O station), data communication system, man-machine interface unit (operator station OPS, engineer station ENS), cabinet, power supply and so on. The system has an open architecture and can provide multi-layer open data interface.

2.The hardware system has high reliability, easy maintenance and advanced technology in harsh industrial sites. The underlying Chinese software platform has powerful processing functions, and provides convenient configuration of complex control systems and users to develop special advanced control algorithms. Easy to configure, easy to use. Multiple fieldbus standards are supported to accommodate future extensions.

3.The design of the system adopts suitable redundancy configuration and self-diagnosis function from diagnosis to module level, which has high reliability. The failure of any component in the system will not affect the work of the entire system.

4.The parameters, alarm, self-diagnosis and other management functions of the system are highly concentrated on the CRT display and printed on the printer, the control system is really dispersed in function and physics, and the utilization rate of DCS and the whole system is at least 99.9%; The average trouble-free time of the system is 100,000 hours, which realizes the complete monitoring of nuclear power, thermal power, petrochemical, chemical, metallurgy and building materials.

5.The concept of "domain" : the large-scale control system is divided into a number of relatively independent sub-systems with high-speed real-time redundant networks, a sub-system constitutes a domain, each domain shares management and operation data, and each domain is a fully functional DCS system in order to better meet the use of users.

6.Network structure reliability, openness and advanced nature. In the system operation layer, redundant 100Mbps Ethernet is used; In the control layer, the redundant 100Mbps industrial Ethernet is used to ensure the reliability of the system. In the field signal processing layer, the 12Mbps PROFIBUS bus connects the central control unit and the various field signal processing modules.

7.Standard Client/Server architecture. Some DCS operating layer adopts Client/Server structure, open and reliable operating system. The operating layer of the system adopts WINDOWS NT operating system. The control station adopts the mature embedded real-time multi-task operating system QNS to ensure the real-time, security and reliability of the control system.

8.Standard control configuration software. The system adopts IEC61131-3 standard control configuration tool, which can realize any monitoring and control requirements. Scalability and tailoring to ensure economy.

DCS generally controls scale

1.Input/output signal type

The DCS process controller should be able to directly receive or process the following types of input and output signals, including analog input, digital input, analog analog output. Digital output.

2.Functional requirements of DCS system

The system generally has control function, continuous control, discrete control function, system monitoring function, monitoring software function including the overall picture, grouping picture. Trend screen, alarm screen, graphic screen, bar chart, etc.