Research On Real-Time Database System Of Process Industry And Its Application

Real-time Database is the integration based on the technologies of real-time control and database system,which is widely used in the fileds where there are urgent demands on the functions of database system and the properties of real-time transaction.The RTDBS(real-time database system) has explicit time limitations on data and transactions. Furthermore,the validity of database system is based not only on the logic result of transactions,but also on its time.Real-time data processing,placement and integration are very importment issues in process industry.They can't be fully solved by Distributed Control System(DCS) and relational database.The RTDBS can provide high-speed,real-time data services,and can integrate different control systems and constitute data platform of process enterprise together with relational database.It plays an important role in the information integration in process CIMS(Computer Integrated Manufacturing System).In this thesis,data characteristic and transactions characteristic of RTDBS were analyzed.The concurrency control protocols in RTDBS and in traditional database were discussed in contrast.Process data compression technology was studied for large amounts of real-time data processing and placement in process industry.Issues including mathematical description of data compression,several commonly used data compression methods,SDT(Swinging Door Trending) algorithm were analyzed in detail.A new SDT algorithm based on bias feedback was presented.Simulation experiments and the compression processing of practical data showed that the algorithm could identify and deal with anomalous data.The restoration errors were controllable when there were noises in process data.The research on OPC technology for large amounts of real-time data integration in process industry was done,including OPC object interface, OPC data access specification and COM component technology,etc.The realization of OPC client softsware was given.Test of the client verified the feasibility and effectiveness of the scheme.The OPC technology was applied to a control platform composed of MATLAB7.0 and B&R PLC. The fuzzy adaptive PID algorithm based on the platform was applied to a temperature plant.The control performance was well.Finally,Process Information Manage System(PIMS) for MDI project of a well-known chemical enterprise was designed using PI RTDB platform,including real-time database,flow charts,real-time data reports, SQC,etc.The PIMS was successfully applied to practical production.