In special control fields, such as nuclear power plant control system, the meaning of DCS is mistakenly called digital control system, and its essence is still distributed operating system.
In domestic automatic control industry, it is also called distributed control system. Compared with centralized control system, it is a new computer control system, which is developed and evolved on the basis of centralized control system.
Extended data
Hardware architecture
1, field control unit
The field control unit is generally far away from the control center and installed near the field. Its highly modular structure can be configured into process control units with different sizes from several monitoring points to hundreds of monitoring points according to the needs of process monitoring and control.
The structure of the field control unit is to install many boards (or cards) with scattered functions in the board box according to a certain logical or physical order, and each field control unit and its control management level are connected through the bus to realize information interaction.
The hardware configuration of the field control unit needs to complete the following contents:
Plug-in configuration: according to the system requirements and control scale, configure hardware devices such as host plug-in (CPU plug-in), power plug-in, I/O plug-in and communication plug-in; Hardware redundancy configuration: Redundant configuration of key equipment is an important means to improve the reliability of DCS. DCS can usually realize redundant configuration of host plug-ins, power plug-ins, communication plug-ins and network and key I/O plug-ins.
Different DCS are installed on hardware, and the installation of various plug-ins in the plug-in box will have corresponding logical or physical order. In addition, field control units are usually divided into two types: basic type and extended type. The so-called basic model means that all kinds of plug-ins are installed in a plug-in box, but more often, an extensible structure is needed, that is, a field control unit also includes several digital input/output expansion units, which are connected together through a bus.
In essence, the structural form and configuration requirements of the field control unit are consistent with the hardware configuration of modular PLC.
2. Console
The operation station is used to display and record the process data from each control unit, and it is the operation interface for people to interact with the production process information.
A typical operating station includes a host system, a display device, a keyboard input device, an information storage device and a printout device. , which mainly realizes powerful display functions (such as analog parameter display, system status display, multi-screen display, etc.). ), alarm function, operation function, report printing function, configuration and programming function, etc.
In addition, DCS operation station is divided into operator station and engineer station. From the system function, the former mainly realizes general production operation and monitoring tasks, and has the functions of data acquisition and processing, monitoring screen display, fault diagnosis and alarm.
Besides the general functions of operator station, the latter should also have the functions of system configuration and control target modification. From the point of view of hardware equipment, the engineer station and operator station of most systems are combined into one, and only one engineer keyboard is used to distinguish them.
Baidu Encyclopedia-Distributed Control System
Baidu encyclopedia -DCS