摘 要：本文根据中国城市小区的供水要求，设计了一套基于PLC的变频调速恒压供水系统。变频恒压供水系统由可编程控制器、变频器、水泵机组、压力传感器、工控机等构成。本系统包含三台水泵电机，它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速，运行切换采用“先启先停”的原则。压力传感器检测当前水压信号送入PLC，与设定值比较后进行PID运算，从而控制变频器的输出频率和电压，进而改变水泵电机的转速来改变供水量，最终保持管网压力稳定在设定值附近。通过工控机与PLC的连接，采用组态软件完成系统监控，实现了运行状态动态显示及数据、报警的查询。57231

毕业论文关 键 词：恒压供水，变频调速， PLC，组态

Abstract: According to the China city residential water demand, this paper designs a set of water supply system of frequecey control of constant voltage based on PLC .Variable frequency constant pressure water supply system consists of a programmable controller, inverter, water pump, pressure sensors, industrial control computer. This system includes three water pump motor, they are composed of variable frequency circulating operation mode. For three-phase motor soft start and frequency conversion speed regulation by frequency converter, operation switch adopts the "start stop" principle. The pressure sensor detects the pressure signal into the PLC, compared with the set value after PID operation, the output frequency and voltage to control the frequency converter, and then change the water pump motor speed to change the water supply pipe network pressure, finally keep stable around the setting value. By connecting the PLC and industrial computer, monitor system using configuration software, to achieve the dynamic operation state display and query data, alarm.

Keywords: constant-pressure water supply,variable frequency speed-regulating, PLC,  supervision control and data acquisition.

目录

1 绪论 4

1.1 课题的研究背景 4

1.2 变频恒压供水系统的研究现状 4

1.3 西门子S7-200PLC简介 4

1.4 本课题的主要研究内容 5

2 恒压供水系统控制方案确定 5

2.1 变频恒压供水系统的理论分析 5

2.2 变频恒压供水系统的组成 6

2.3 变频恒压供水系统控制流程 7

3硬件设计 8

3.1设备的选型 8

3.2 系统主电路分析及其设计 10

3.3 系统控制电路分析及其设计 11

3.4  PLC的I/O端口分配及接线图 12

4 软件设计 14

4.1软件设计分析 14

4.2 PLC程序设计 15

4.3 PID控制器参数整定 18

5 组态及仿真 20

5.1 组态王的通信参数设置 20

5.2 新建工程与组态变量 21

5.3 组态画面 22

5.4 监控系统界面 23

结论 25

参考文献