毕业设计论文_基于plc的排水系统控制设计.docVIP

基于PLC的污水坑水位控制系统设计 摘 要 PLC（可编程逻辑控制器）是一种基于数字计算机技术、专为工业环境下应用而设计的电子系统。它具有功能强大、使用可靠、维修简便等许多优点。由于可编程序控制器安全性高、功能完善、性能稳定、应用广泛，因此，污水坑水位控制系统中的控制部分采用可编程序控制器来控制。在本系统中，采用西门子S7-200型PLC控制潜水泵的起停，其中PLC选用DC24V输入、DC24V继电器输出。污水坑水位控制系统的操作方式分为手动方式和自动方式。本课题主要任务是自动控制方式部分，用4个水位开关检测污水坑的水位，PLC根据水位情况控制潜水泵的起停。该设计中采用4台潜水泵循环工作方式取代了通常的3用1备工作方式，更加合理的分配了潜水泵的起停，提高了每台潜水泵的利用率，避免了电动机的频繁启动，对电动机的保护也更加完善。最后通过编程实现自动控制。 关键词：水位控制，潜水泵，PLC The design of Sewage pit Water level control system Based on PLC Abstract PLC (programmable logic controller) is one kind of electronic system based on technology of digital computer, and designed specially for using in industrial environment. It has many merits such as powerful function, reliable use and easy-mending. With the rapid development of microelectronic and computer technology, PLC has widely used in industrial control area. Because the PLC is safe, stable, reliable, and applied widely, the PLC is used as the controller for the sewage pit water level control system. In this system, using Simens S7-200 PLC to control the start and stop of diving pumps, in which PLC selects DC24V of input, DC24V relay of outputs, and has DC24V voltage-stabilized source. The sewage pit water level control system operating mode divides into the manual way and automatic way. This topic primary mission is the automatic control way, with 4 water level switch examining sewage pit water level, PLC according to the water level situation control the start and stop of diving pumps. To instead of past method which three pumps is working and one is for ready, the new cycle work method is applied in this design. It makes the start and stop of the diving pumps more reasonable. And at the same time, it makes the diving pumps work more efficiently and avoids to start the electric motors frequently. So the electric motor can be better protected. At the end the LAD program of the sewage pit water level control system is provided. Key words：water level control, diving pumps, PLC 目 录 摘 要 I Abst