Based Opc And Fuzzy Control Sewage Aeration Monitoring System Research And Design. "

With the modern industrial process control systems becoming larger and more complicated, performance requirements to the control systems are becoming stricter. On the one hand, openness and inheritable development to the systems are strongly needed because of the more and more hardware using in the industry. On the other hand, the more complicated systems need a control algorithm that doesn't depend on the exact model of the systems. In allusion to this matter, a fuzzy control system for the waste water aeration based on OPC technology is proposed and designed.Firstly, technologies and technics of one waste water treatment plant in Zhongshan city are analyzed as well as aeration process. Electric control project based on PLC and VFD is designed in considering of feasibility, efficiency and engineering cost of the system. Siemens PLC-200 is selected as controller to control frequency of power supply by VFD for blower, as to adapt rotation speed of blower, and furthermore, which influence the aeration rate, aiming to control dissolved oxygen concentration of effluent from biochemical pond.And then fuzzy control system for waste water aeration is mainly designed, which means fuzzy control system applies to waste water aeration process. The design of fuzzy controller is the key of fuzzy control system design that consists of universes selecting, membership functions determining, fuzzy rules establishing and ultimately generation of fuzzy inquiring tables. And next, mathematical model of the aeration process is proposed, so as to compare traditional PID control with fuzzy control. MATLAB simulation shows that fuzzy control is more superior with no overshoot, and less settling time.Finally, the thesis designs monitoring system of waste water aeration established in configuration software, iFIX platform, whose data interaction between upper computer and lower computer via industrial ethernet and OPC. Fuzzy control algorithm is programmed in iFIX scheduling based on Visual Basic. Historical curve of dissolved oxygen concentration and frequency output is drawed with the historical data. Fuzzy control is superior to PID control with less average error of dissolved oxygen concentration and less mean square deviation of frequency output by analyzing these data, in other words, fuzzy control achieves high accurate and stable control performance. Indeed, it is fuzzy control that could enhance system performance.