基于PLC的恒压供水控制系统设计-毕业论文.doc

英文摘要 PAGE 12 毕业设计（论文） 设计（论文）题目： 基于PLC的恒压供水控制系统设计 摘 要 原始的供水方式如气压罐供水等供水方式在用户用水高峰期时经常出现水压低，工作不稳定的情况从而影响用户使用。在消防用水时也可能由于供水压力不足而不能及时扑灭火灾。因此，本文针对传统供水方式的不足之处设计了一款可使网管水压保持在水压设定值上的恒压供水控制系统。该设计以PLC和变频器作为系统的控制元件，用压力变送器实时监测用户网管处的水压，将水压以模拟量信号传送给PLC，PLC对此模拟信号进行分析计算，再将计算结果传送给变频器，变频器和PLC通过改变系统水泵接入的数量或调整电机运行频率的方式实现对水泵转速的控制，以此来保持管网水压处于恒定状态。另外，本次设计采用的SIEMENS公司S7-200系列PLC （CPU226）和SIEMENS公司MicroMaster430型号的变频器性价比高、功能齐全而且操作和接线简便，所以具有很大的使用和推广价值。 关键词：恒压供水；PLC；变频器 ABSTRACT The original water supply mode, such as air pressure tank water supply, often has low water pressure and unstable operation during the peak period of water consumption, which affects the use of users.The fire may not be put out in time due to insufficient water supply pressure. Therefore, this paper designs a constant pressure water supply control system which can keep the water pressure on the set value of water pressure. In this design, PLC and frequency changer are used as the control elements of the system. The pressure transmitter is used to monitor the water pressure at the network management of the user in real time, and the water pressure is transmitted to PLC as analog signal. PLC analyzes and calculates the analog signal, and then transmits the calculation result to the frequency changer. The frequency changer and PLC realize the speed of the water pump by changing the number of water pumps connected to the system or adjusting the operating frequency of the motor In order to keep the water pressure in a constant state. In addition, the S7-200 series PLC (cpu226) of Siemens company and Micromaster 430 model frequency changer of Siemens company adopted in this design have high cost performance, complete functions and simple operation and wiring, so they have great use and promotion value. Key Words：Constant pressure water supply; PLC; Frequency changer 目 录 目 录 TOC \o 1-3 \h \z \u 1绪论 1 1.1 选题背景 1 1.2 课题研究的目的和