Design And Implementation Of Train Segment Sewage Treatment Control System Based On KingView

In order to save water resources and protect the environment,the sewage treatment system has been widely applied in various fields,such as industry,agriculture,commerce,construction,medical treatment and catering.To ensure that the effluent discharge meets the National Sewage Treatment Discharge Standard,appropriate sewage treatment processes for the water quality and water quantity should be carefully selected and designed.Meanwhile,it is also extremely essential to design and carry out an advanced automatic sewage treatment control system.In this thesis,a train segment sewage treatment control system is designed and developed,according to the actual demands of consumer from a real sewage treatment project for a train segment,and a more in-depth study of the liquid level control problem is conducted.Taking the water quality character and effluent standard of a train segment sewage into account,taking A~2O process as an example,the main process flow of sewage treatment is analyzed in this thesis.The functions needs of the sewage treatment control system as well as the requirements of data transmission network are analyzed.Then,the overall design of the control system is carried out.The control system scheme with three-layer structure consisting of field equipment layer,control layer and regulatory layer is constructed based on ideas of centralized management and decentralized control.The field layer provides the environmental condition for control equipment and the arrangement,connection and operation of instruments and apparatus.The control layer is responsible for the data collection and operation control,it can also accomplish the data communication with regulatory layer.The configuration is established by regulatory layer according to the field data realizing the monitoring of the whole system,information management and Web release.In accordance with the communication demand of each subsystem,the system network design scheme is determined which is a combination of industrial Ethernet and field bus.Considering the importance of pool level control in sewage treatment process,the mathematical model of the tank level system,taking the characteristics and mechanism of the anaerobic pond level control into consideration,is established first based on the analysis of the influence of sewage level on the A~2O process.And then,to reduce the difficulty in adjusting PID parameters and realize unmanned operation,an anaerobic tank level control algorithm is proposed based on fuzzy PID,in order to adapt to the dynamic changes of water quality and water quantity.The algorithm proposed is simulated in Matlab environment.The results show that the fuzzy PID control algorithm designed can realize quick adjustment of sewage liquid level to the set height.In addition,the fuzzy PID control system has good robustness by the interference verification.In order to realize the automatic control of the whole system,the program creation for S7-300 PLC controller is accomplished by adopting STEP V5.5.According to the requirements of remote monitoring and web browsing,the configuration of host computer monitoring system and the release of Web server are completed by utilizing King View configuration software.Aiming at the demand of system control and data transmission,the Ethernet and Profibus network are selected to realize the communication and data interaction of three-layer system.The sewage treatment control system designed is simulated and tested in the laboratory environment.The results show that the sewage treatment control system designed and developed in this thesis can effectively accomplish the automatic control,remote monitoring,and web browsing and other expected functions of sewage disposal pool are realized.Through the control of the level of the anaerobic tank and other sewage treatment tanks,the hydraulic retention time of the sewage treatment process is ensured,and then the effluent can reach the standard.