毕业设计 基于PLC的工业污水处理系统的设计.doc

河南科技学院 20届本科毕业论文（设计） 论文题目： 学生姓名： 所在院系： 机电学院 所学专业： 导师姓名： 完成时间：200 年 月 日 Design based on the PLC industrial sewage processing system Abstract In recent years, sewage treatment plant has already become one of the most important infrastructures in every city, and especially in small and medium-sized ones, to build and expand such plants has been on the local governments’ top agenda to improve peoples’ life. With the development and improvement of automation technique and computer technology, automation level of sewage treatment plants has also made a corresponding leap. While PLC has series of merits such as: mature technique, fine universal property, high reliability, flexible to install, convenient to expand, excellent cost performance, etc, which have enabled it gain a more and more widespread application in industrial control. This paper will mainly introduce the composition and function of the automatic control system in sewage treatment plants and several problems that may occur in the practical use of the system and the possible solutions to them. Since the transformation by employing PLC control system in sewage treatment, the reliability of automatic control has been advanced, which has not only reduced workers’ work intensity, but also improved the operational efficiency of the sewage treatment plants, thus has made the scientific administration of manufacturing in sewage treatment plants possible. Key words: PLC, Sewage treatment, SBR reaction 目　　录 1 引言 1 2 系统总体设计 1 3 控制系统设计 2 3.1 除渣 2 3.2 除油 3 3.3 中和处理 4 3.4 除有机物 5 3.5 除盐 6 4 PLC选型 7 4.1 PLC的I/O口分配 8 4.2 系统外部接线图 9 4.3 软件设计 10 5 上位机与下位机的设计 10 5.1 上位机设计 10 5.2 下位机设计 11 5.3 上位机与下位机之间的通信 12 5.3.1 PLC的通信功能 12 5.3.2 PLC的通信协议 12 6 通讯网络 15 6.1 中央控制室 15 6.2 控制分站 15 6.3现场监测仪表 15 7 结束语 16 致谢 17 参考文献 18 1 引言 随着国民经济的发展，国家对环保事业也越来越重视，越来越多的污水处理厂正在兴建或待建中，只要稍上规模的污水处理厂，无一例外地都使用了PLC作为其自控系统的主要设备。 工业污水处理自动控制近年来一直是控制领域研究的热点之一。伴随着技术进步、工艺改进、系统完善的同时,对工业污水处理的控制也提出了更高的要求。本系统构建了基于PLC的工业控制网络,采用PC机和PL