Research On Control And Serial Communication For Analogs Based On DCS In Wastewater Disposal

The progress state of control system research for wastewater disposal plant in home and overseas is introduced in this article. According to the character of the sewage treatment plant of our country , we have adopted distributed control system(DCS) as the solve scheme for monitoring system. Three important analogs in wastewater treatment: PH, COD and DO are measured and controlled on-linly and in real time with modularization design method.Two level DCS of wastewater treatment is made up of AT89C51 singlechip system as the measure and control unit for analog in the locale , and PC as the monitoring unit. Data disposal is done based on fault diagnosis and data fusion, the long-range data communication between local unit and PC goes through RS-485 protocol, and the local data can be transported and saved to dynamic database in PC in real time for later use. The design process of software and hardware for data acquisition and data communication of analog has been shown in this article.Monitoring and control software of wastewater disposal is made up of three parts mainly: the main control application program based on VB, which is used for data acquisition, data communication, building dynamic database and creating interface of human-computer interaction; the data disposal module based on Matlab platform, which is used for calculation of complicated control arithmetic; the data monitoring system based on LabVIEW, which is used for dynamic show for analogs. Data communication among every modules are accomplished through Dynamic Link Library(DLL) and Dynamic Data Exchange(DDE).