Software Design For SCADA System Data Server Based On Qt

The data server software of SCADA system scheduling-side is an important part of scheduling-side software. Data server software is more based on UNIX operating system or LINUX operating system, also based on Windows operating system. Different operating system platforms require different versions of the data server software, the system open-future is poor. Therefore, the design of scheduling-side SCADA system data server software which has the characteristic of cross-platform enables that the open future of software platform is more and provide comprehensive and flexible platform solution.On the basis of summarizing the research and design which has been accomplished, this dissertation implements a data server software of SCADA system by the use of Qt as development platform. Main tasks are as follows:Firstly, a detailed needs analysis including software modules and associated data structure is defined, and the UML sequence diagram of the telemetry, remote commutation, remote control is completely analyzed. Secondly, the dissertation uses Qt's signals and slots mechanism to implement a large number of callback functions of SCADA system software design. Then the dissertation elaborates the operation of Qt-based multi-thread API, and discusses in detail the relationship between it and the signals and slots mechanism. And then for the function modules of data server software, it elaborates by detailed the procedure process and their key technologies of the human-computer interface, network communication, information processing, data recording stored. Finally the author tests the Qt server software in a lab environment.Aiming at the defect that most data server software do not have data compression function, the dissertation analyzes in depth the data compression algorithm which is specially useful for text and database compression including Huffman compression algorithm, adaptive (dynamic) Huffman algorithm, and the Swinging-door algorithm of lossy compression method, and analyze the Huffman algorithm compression ratio, coding efficiency and other important indicators. On the basis of this the dissertation completes the compression and decompression process analysis and their programming flow-progress diagram both of the adaptive Huffman coding and Swinging-door algorithm.