Design Of Industry Process Control System Applying PLC And Its Application In Fountain Water Supply

With the development of technology of programmable logic controller, and because of its high reliability, high ratio of performance to price, PLC has found more and more broad adaptability in industry spot and convenient technique expansibility, so PLC become more and more abroad in the automation process control in industry.Base on this background, after comparing with performances of several ordinary types of domestic PLC, this thesis discusses the ordinary design methods and the measurements to improve reliability of PLC. The emphasis of this essay lies in the discussing methods of hardware and software in PLC control systems compare and synthesize method of experience design, logic design, time-order design, and sequence design; and also the designing method of human-machine interface of control system. To solve some ordinary practical problems in the process of PLC real-time control spots, this essay gives some suggestions, such as to power supply interface, extending to PLC inputs and outputs and system interlocking problems. Finally, based on engineering of Zao Shi Hydro-Project automation water supply system, this essay designs a whole automation control engineering. To accomplish this, And in order to satisfy the system's performance-criteria, the S7-226 PLC of Siemens PLC serials S7-200 is used because of its excellent high ratio of performance to price, as well as its better developing plat and a large amount of references which has found its extensive application in small scale PLC control systems. In this essay, the STEP7/WIN software supplied by Siemens is taken into use; and debug could be done in the Windows2000. And the frame view 5.5 is used to implement the real-time inspection, Modbus is used between hot-computer and target-computer to implement communication.The test operation has proved the good reliability and real-time which has proved the design requires and the economic efficiency.