Research Of Sewage Treatment Control System Based On PLC

Zhejiang is a leading province in private economy and manufacturing, while the majority of her private enterprises put inadequate investments on sewage disposal and lack of latest technology. With the further development of the manufacturing, the more sewage is discharged into the environment, the worse it will threaten people's physical and mental health. Therefore, it is urgent to accelerate the implementation of sewage disposal project.This paper is to take a certain chemical plant as a sample. The existing sewage disposal process is mainly fulfilled by handwork with low working efficiency and poor sewage disposal capability. Based on this, therefore, it is urgent to transform the existing one and establish a set of new automatic control system for sewage disposal with high-performance and high reliability.According to the project requirements, this paper is to design a set of automatic control system for sewage disposal which integrate PLC technology, configuration software technology and network communication technology in it. The control system mainly consists of a computer, PLC, communication module and sensor composition. It is used to detect some relevant parameters, such as system liquid level, temperature and PH value, and to control some implemental equipment like pumps, mixers, scrapers and valves. The section of Software design part adopts Kingview and GX Developer to develop the Host Computer Monitoring Software and the lower computer user software. Through the hardware and software design, the system is able to realize three kinds of linkage ways to control, which are on-site manual control, PLC control and central control, and is to achieve the effect of centralized monitoring and decentralized control.In the process of sewage disposal, PH value is one of the important parameters to attribute water quality, and the effect of controlling PH value in the neutral pool directly affect water quality. In order to improve its performance and accuracy, the system utilizes PID control to stabilize PH value within a given range for ensuring a good control effect.