Research on Power Plants Data Acquisition System Based on MODBUS
|School||Harbin Institute of Technology|
|Keywords||power plant data collection system MODBUS redundant network|
More and more monitor equipment applied field bus communication protocol in the monitor system of power plant. The current DCS system technology has not opening character, and can link the joint directly. A data collection system based on filed bus communication protocol is developed for the power plant to make the DCS take on the opening character, and the DCS can directly connect the equipment satisfied the protocol so as to increase the economy character of the system.Firstly, the data collection system model of power plants is discussed in this paper. And then, the existing means and protocol of communication and redundant network are researched deeply. Afterwards, with data features of power plants considered, it becomes communication protocol of data collection systems that taking field bus protocol into distributed control system of plants. A new data collection system of plants based on MODBUS is designed so that data transmission speed is improved, system’s fault tolerance is enhanced and data collection capacity of distributed control system is improved. Nowadays, MODBUS has been supported by many manufactures and a lot of products are supported on MODBUS protocol so that it becomes easy to add the other manufacturers’equipment to the data collection systems.In this paper field bus MODBUS protocol in data collection systems of plants is researched for applying. According to data characteristics of power plants, the paper raises that industrial control computer is the main station and high-speed singlechip is the core of the assistant station, and a detailed analysis is made on hardware and software structure of systems. Microprocessors ATmega128 on the basis of reduced instruction set is selected as high-speed singlechip of the assistant station so that the bus can be used to make high-speed data communication and deal with data on real-time. Industrial control computers in main stations can both effectively manage lots of assistant stations and support equipments on MODBUS protocol, and receive and handle field data by complex algorithm that it shows the powerful capacities of dealing with data, calculation and high reliability after long time running. Designed by redundant processing approach through main station cooperating with assistant ones, a new set of dealing with the failure mechanism is designed that both reduces the burden of main stations and make use of resource in assistant station. Meanwhile, tbat redundant channel selection should be made by assistant stations accord with distributed control system theoretics.According to data characteristics of plants, the paper designs the representative thermal resistance data collection card as the exam system in the assistant station and the corresponding hardware devices are produced. Two assistant stations are produced in order to exam the system. According to the protocol and redundant modes of overall system, the bottom divers program of main station is designed so as to further develop and to debug by simple display software designed. In assistant station is a complete data collection and communication with main station program. Exam results proves that calculation capacity and accuracy of data collection. Finally, an improvement schedule is raised according to real situation.