Research Of SFC Control & Collect Real-Time Data In DCS System

With the development of computer technology, industry control technology, graphics technology, network technology and field bus control technology, DCS(Distribution Control System) is enjoying a rapid development and tends to be more open, networking and intelligent. DCS system can help enhance enterprise's automatization and management capability, while produce huge economic and social benefits, so it has enormous applicable and research value.The thesis is developed for the following aims:First we introduce the systematic structure and functional features of DCS, while describing the details of DCS development and the structure and features of plantweb of DeltaV system.Combined with the practice, a practical example of the SFC(sequence function control) is given, since DCS sequence control has no good graphical interface, which can not adjust the controlling parameters flexibly according to practical requirement. This example provides a better HMI interface, via the exploitation with the SFC graphical interface , which can reach more flexible control strategy.Based on studying and analyzing relevant theories on key technologies of real—time database, the thesis makes deeper analysis on data compression of real—time and S2PL-HP concunrrency control protocol, and then supported by DeltaV system, the author puts forward to the study of real—time database and history database.As for the openness of DCS system, the thesis makes research in the COM(Component Object Model), data access method of OPC, (OLE for Process Control), interface access, and access-to-data method of it. The client software is designed based on OPC technology and combining with practical requirements, through which real—time data can be obtained from the automatic interface of OPC server for providing information support for enterprise's management information system.