Design And Realization Of Monitoring And Control System For A Sewage Treatment Plant

Wastewater treatment is an important means to promote the recycling of water resources.Automatic sewage treatment system can avoid the influence of artificial factors.The development of sewage treatment monitoring system plays an important role in reducing the incidence of accidents,declining cost of wastewater treatment,the optimization of process control and reducing manual labor.Data which sewage treatment system required for making report,alarm and trend curve is collected from smart meters,the transmission of data is by PLC.And in this paper the applied database is WinCC's SQL database.In order to realize the design of monitoring system better,based on the detailed study of monitoring system for communication network and network protocol,proposed the PROFIBUS fieldbus + industrial Ethernet network as the communication network of the sewage treatment plant,fieldbus using PROFIBUS-DP protocol while industrial Ethernet using TCP-IP protocol,realizing the data sharing of sewage treatment.The content of DO in sewage treatment process is closely related to wastewater treatment effect.DO model has characteristics of nonlinear,time-varying,coupling,and parameters and structure uncertainty,etc.Aiming at these problems,based on a detailed study of commonly used model and control method of DO,a method which combined PID with fuzzy logic is proposed to control the concentration of DO.The simulation of fuzzy-PID controller is carried out through MATLAB,and the feasibility of the scheme is proved,then program PLC to meet actual demand.Based on the PROFIBUS fieldbus + industrial Ethernet ring network as the communication network scheme of the sewage treatment plant,this paper finally using C language and VB language to complete the design of man-machine interface in the WinCC configuration software,interface enables the control of equipment,the display of equipment operation status and process data,the recording of alarm,the display of real-time curve,the processing of report,and other functions,the system meets all functional requirements steadily after debugging.