Sewage Treatment Automatic Control System Based On S7-300 PLC

With the development of modern industrial control automation,the disadvantages of the low degree of automation of the traditional sewage treatment control system and the unsatisfactory treatment effect need to be solved.Therefore,improving the controllability of the sewage treatment process,reducing the manual intervention during the operation of the system,and timely collecting the data information of each control link become the development direction of the sewage treatment automatic control system.According to the process characteristics of the sewage treatment process and the overall requirements of the control system,this paper designs an automatic control system for sewage treatment with S7-300 PLC as the core controller.Aiming at the shortcomings of the traditional sewage treatment control system,the overall design scheme of the system was formulated,and the strategy method of precise control of dissolved oxygen concentration was proposed.The hardware design and software design of the system were carried out.The hardware design scheme adopts the control architecture based on industrial Ethernet PROFINET and PROFIBUS-DP bus.The industrial computer is used as the upper computer,the programmable logic controller PLC and the distributed I/O device are the lower computer,which constitutes the multi-bus distributed I/O control system.The software design mainly includes PLC program design,PC software development and touch screen interface design.The STEP 7 programming software is used to complete the PLC control program,the WinCC configuration software is used to design the host computer monitor program and WinCC flexible software completes the touch screen scene.The entire sewage treatment automatic control system combines the latest state of the art and PLC control system technology to provide an effective self-control solution for wastewater treatment.In order to achieve precise control of dissolved oxygen concentration in bioreactor,this paper proposes a fuzzy adaptive PID optimization algorithm to realize the automatic control of blower speed and running state for system dissolved oxygen concentration characteristics,and verify the optimization algorithm through MATLAB software simulation.The sewage treatment automatic control system based on S7-300 PLCdesigned and developed in this paper can meet all the requirements of sewage treatment automation,with remarkable control effect and good reliability and real-time.