基于PLC的恒压供水泵站系统设计_毕业设计论文.doc

PAGE XXXII 南京工程学院 自动化学院 本科毕业设计（论文） 题目： 基于PLC的恒压供水泵站系统设计 专 业： 自动化 Graduation Design (Thesis) Design of Constant Pressure Water-supply System Based on PLC By Jia Ruiyong Supervised by Associate Prof. Liu Yunxia Department of Automation Engineering Nanjing Institute of Technology June, 2013 PAGE \* MERGEFORMAT II PAGE \* MERGEFORMAT II 摘 要 本设计以一个城市小区供水系统作为被控对象，研究基于PLC的变频恒压供水系统，使系统获得较好的性能指标，力求做到使系统运行稳定，操作简单，解决实际供水中问题，保证供水安全、快捷、可靠，目前变频恒压供水系统已在国内外实际供水控制系统中得到广泛的应用。 此变频恒压供水系统由水泵机组，共包括四台水泵电机，其中三台为常规水泵，一台为辅助水泵，其与可编程序控制器、变频器、压力传感器等相关器件组成了一个变频循环运行系统 。系统实时比较管网压力与压力设定值偏差的变化情况，经PLC进行PID运算，由PLC控制水泵电机的变频、工频切换，自动控制水泵电机投运台数和电机转速，实现闭环自动调节恒压供水。 经软件仿真及实验室调试，证明系统基本可以满足设计要求。 关键词： PLC；PID；变频器；恒压供水 ABSTRACT The design of a city district water supply system as a controlled object, the study is based on the PLC constant pressure water supply system, allowing the system to obtain better performance indicators, and strive to make sure that the system is stable and easy to operate, to correct the problem that is the actual water supply to ensure water supply safe, fast, reliable, constant pressure water supply system has been widely used in domestic and foreign real water supply control system. Constant pressure water supply system consists of a pump unit, including a total of four pump motor, three conventional pumps, one for the auxiliary water pump, a variable frequency with a programmable logic controller, inverter, pressure sensors and other related devices cycle operation system. Real-time comparison system pipe network pressure and pressure setpoint deviation changes, the PID operation by the PLC, the PLC controlled pump motor frequency, frequency switching, automatic control of the number of units put into operation the pump motor and the motor speed to achieve constant loop automatic adjustment pressure water supply. The software simulation and laboratory testing, proof system could