基于PLC的变频调速供水系统设计毕业论文

摘  要恒压供水系统装置就是建筑物外的供水管网里的水流进蓄水池，在由水泵抽水至屋顶水箱和建筑物内供水装置。水泵水箱联合给水方式适用的条件是：当建筑外管网压力经常低于建筑内给水系统所需压力，而且建筑内用水量又很不均匀时，采用水泵加压给水，同时采用水箱贮存调节用水量。此方式，一是能使水泵在高效率条件下工作，同时水箱能够贮存调节生活和其他用水量，二是使水泵间断工作，可以利用变频器和PLC来实现对水泵的变频调速控制来达到水泵运行与停止自动化，能及时向管网和水箱充水，也可使水箱容积大大减小。这种给水方式技术上合理，供水可靠，节能，是我过和国外建筑采用的一种常见给水方式。通过对计算机和PLC之间通信协议的研究，完成了上下位机通信设置，开发了计算机监控程序，通过通信模块实现了对恒压供水系统的远程监控和故障报警。系统有效地解决了传统供水方式中存在的问题，增强了系统的可靠性。并与计算机实现了有机的结合，提升了系统的总体性能。关键字：PLC，变频调速，液位检测，自动控制AbstractWater Supply System device water into the reservoir outside the building water supply pipe network, pumping by the pump to roof tank and the building water supply installations. Applicable conditions of the joint water supply of the pump tank is: when building outside the pipe network pressure is often lower than the construction of water supply system within the desired pressure, and the building's water consumption is very uneven, pressurized water pump, while water tank storage supply of water volume. In this way, first, make the pump work under conditions of high efficiency, and tank storage to regulate life and other water use is the water pump stopped working, you can use the inverter and PLC variable frequency speed control of pumps to achieve pump is running and stop automated, timely water-filled pipe network and water storage tanks, also allows the tank volume is greatly reduced. This water supply is technically sound, reliable water supply, energy saving, I had and foreign construction using a common water supply.To complete the communication protocol between the computer and PLC communication settings of the upper and lower machine, developed a computer monitoring program, through the communication module to achieve a constant pressure water supply systems, remote monitoring and fault alarm. System to effectively solve the existing problems in the traditional way of water supply, and enhance the reliability of the system. Computer to achieve the organic combination to enhance overall system performance.Keywords: PLC, frequency control, liquid level detection, automatic control

目  录摘  要 1Abstract 2目  录 3前  言 3第一章 绪论 5第二章 水泵调速运行及变频调速技术 72.1水泵的基本性能参数和特性曲线 72.2离心泵的选用 82.3水泵的结构特点 92.4水泵的安装 10第三章 变频器设计 113.1变频器的概述 113.2变频器的基本结构 123.3变频器的构成 133.4变频器的工作原理 143.5变频器的选型 153.6变频器标准接线图 183.7液位传感器 203.8 三菱FX2N 系列可编程序控制器介绍 223.9 PLC程序设计 28第4章 水泵性能曲线拟合及系统仿真 364.1 双吸Slow200-400I型离心泵的性能曲线拟合 364.1.1单台水泵变频调速运行时的性能曲线拟合 364.1.2单台水泵变频调速运行时的扬程拟合曲线绘制 374.1.3单台水泵变频调速运行时的功率拟合曲线绘制 384.1.4单台水泵变频调速运行时的效率拟合曲线绘制 384.2 开环的变频供水系统仿真 394.2.1 PWM脉冲生成系统仿真 394.2.2 开环变频供水系统仿真 404.3 闭环恒压变频供水系统仿真 42结束语 44参考文献 45致  谢 46