DCS is the abbreviation of central control distributed control system, which is also called distributed control system in domestic automatic control industry. It is a computer control system relative to the centralized control system. It is developed and evolved on the basis of the centralized control system
Firstly, the framework of DCS - system network, which is the foundation and core of DCS. Because the network plays a decisive role in the real-time, reliability and expansibility of the whole DCS system, Jinan hanorda Control Technology Co., Ltd. has made careful design in this regard. For the system network of DCS, it needs to meet the requirements of real-time, that is, to complete the transmission of information within a certain time limit. The "determined" time limit mentioned here refers to that in any case, the information transmission can be completed within this time limit, which is determined according to the real-time requirements of the controlled process. Therefore, the index to measure the performance of the system network is not the rate of the network, that is, the number of bits per second, but the real-time performance of the system network, that is, how long it can ensure the transmission of the required information. The system network also needs to be very reliable, and the network communication can not be interrupted under any circumstances. Therefore, the central control and Hollysys DCS operated by the company adopt the network topology of double bus, ring or double star. In order to meet the requirements of system expansibility, the number of accessible nodes 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, on the other hand, the system network can also run in a light communication load state to ensure the real-time and reliability of the system. During the actual operation of the system, the online and offline of each node may occur at any time, especially at the operator station. In this way, the network reconstruction will be carried out frequently, and this operation can not affect the normal operation of the system. Therefore, the system network should have a strong online network reconstruction function.
其次，这是一种完全对现场I/O处理并实现直接数字控制（DDC）功能的网络节点。一般一套DCS中要设置现场I/O控制站，用以分担整个系统的I/O和控制功能。这样既可以避免由于一个站点失效造成整个系统的失效，提高系统可靠性，也可以使各站点分担数据采集和控制功能，有利于提高整个系统的性能。DCS的操作员站是处理一切与运行操作有关的人机界面（HMI-Human Machine Interface或operator interface）功能的网络节点。
Secondly, this is a kind of network node that completely processes the field I / O and realizes the function of direct digital control (DDC). Generally, a set of DCS shall be equipped with on-site I / O control station to share the I / O and control functions of the whole system. This can not only avoid the failure of the whole system caused by the failure of one station and improve the reliability of the system, but also enable each station to share the data acquisition and control functions, which is conducive to improving the performance of the whole system. The operator station of DCS is a network node that handles all human-machine interface (HMI human machine interface or operator interface) functions related to operation.
The engineer station is a network node for offline configuration, configuration and online system supervision, control and maintenance of DCS. Its main function is to provide tool software (i.e. configuration software) for DCS configuration and configuration, and monitor the operation of each node on the DCS network in real time when DCS is running online, so that the system engineer can timely adjust the system configuration and the setting of some system parameters through the engineer station, Keep DCS in working state at any time. Different from the centralized control system, all DCS require system configuration function. It can be said that a system without system configuration function cannot be called DCS.
The above is a detailed introduction about the DCS card of Zhejiang University central control. I hope it will be helpful to you If you have any questions, please contact us We will provide you with professional service http://www.sdjkyqyb.com