Research And Implementation Of Data Acquisition And Supervisory Control System Based On Lightweight RTDB

The technology of Internet of Things(IOT)is an important part of the new generation of information technology.As industrial automation requirements are improved constantly,the industrialization and IOT are mutually combined to realize the equipment monitoring and production status analysis in industrial process.In the supervisory control and data acquisition(SCADA)based on IOT,the data storage and transmission is a key technology.Especially for the monitoring system with high real time and large amount of data collection which works on the data acquisition site for a long time,the high-efficiency and stability of data acquisition need to be guaranteed.Therefore,this paper proposes the method of realizing lightweight RTDB(Real-time Database)by utilizing Redis main memory database and high-powered PostgreSQL database and combining with data compression processing and RabbitMQ real-time data transmission technology,thus to meet the SMEs'(small and medium-sized enterprises)need to monitoring the industrial production process and reduce the costs of purchasing and large-scale and expensive RTDB.In consideration of the need of high-efficient storage of data in RTDB,LZW algorithm in two-stage compression strategy based on preprocessing is optimized,so as to reduce the time spending on data compression and decompression and improve the data query efficiency.In this dissertation,the study background and significance,domestic and overseas study status as well as the related technologies are introduced firstly.Secondly,its architecture and functional structure are designed according to the actual needs.The lightweight RTDB—the core of the monitoring system is designed,and moreover,the application process of combining Redis PostgreSQL,RabbitMQ and two-stage compression strategy based on preprocessing is stated.Thirdly,the communication service function of data interaction among configuration client which realizes humancomputer interaction,upper computer and lower computer is designed.In the end,the LZW compression algorithm is studied and optimized.The work of this paper mainly includes:Firstly,narrate the overall needs of SCADA,design its architecture and functional structure,and describe the operating platform and key development technology applied in this project.Secondly,study the function and core technology of RTDB.Study RabbitMQ which realizes real-time communication aiming at the real time transmission of monitoring data and persistent storage of historical data,and meanwhile,construct the high available Redis Cluster to realize the cache to real-time data;design data compression strategy and history library structure in detail according to the needs of compression storage of historical data.Thirdly,study the application of configuration client in monitoring system,divide its functional module according to functional requirement,and state the application value of front end and back end isolation technology in configuration client.Fourthly,analyze the process of communication between upper computer and lower computer in monitoring system,and realize data acquisition service and equipment control service with NodeJS.Fifthly,study the LZW algorithm which is suitable for historical data compression,optimize LZW starting from encoding length and dictionary structure by taking shortening the time of data compression and decompression as the target,and verify the experiment validity through comparing.