Differences between DCS and SIS

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Differences between DCS and SIS [Copy link]

 

DCS, or Distributed Control System, is a centralized and distributed control system based on microprocessors. The first distributed control system was introduced in the mid-1970s, and it has been widely used in the field of industrial control until now. The main characteristics of a distributed control system are to achieve centralized management and decentralized control through real-time monitoring.

SIS, or Supervisory Information System, is a plant-level automation information system that integrates real-time process monitoring, optimization control and production process management. The goal of SIS is to achieve the sharing of real-time production information and management information through large-scale data collection and processing. On this basis, through calculation, analysis, statistics, optimization, and data mining, the production process monitoring, process equipment performance and economic index analysis and operation guidance of chemical plants can be realized. The main characteristics are reflected in the system decision support.

The DCS system focuses on real-time monitoring and precise control, with the purpose of safe and stable operation of equipment. SIS is based on DCS, and through real-time analysis of monitoring data, the real-time command and dispatch of the production operation of the whole plant is carried out to ensure the operation quality and economy of the entire production system. Therefore, SIS system and DCS system are systems facing different levels, different goals, and have different functions. They are both interconnected and have significant differences. These two systems should coexist, cannot replace each other, and some functions can also overlap.

In short, DCS controls the entire process under normal daily conditions. However, when normal operations cannot achieve control, SIS will intervene to reduce the possibility of accidents.