基于PLC的恒压供水控制系统设计
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摘要
本论文根据某些工业生产或特殊用户的供水要求，设计了一套基于PLC的变频调速恒压供水系统。该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电压和频率，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。
关键词：压力传感器；变频器；恒压供水
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ABSTRACT
The text based on certain industrial water supply or special user requirements,and design a PLC-based frequency control water supply system. The system consists of a programmable controller, inverter, water pumps, pressure sensors and industrial machines. The system includes three pump motor, they form the loop variable frequency operation mode. Three-phase inverter is used to achieve the pump motor soft-start and frequency control, operation switches between \pressure sensor detects the current signal into the PID operation with the set value after comparing PLC to control the output voltage and frequency of the inverter, then change the water pump motor speed to change the water supply and ultimately keep the pipe network pressure stabilized at set setting nearby.
Key words: Pressure sensors; inverter; Water Supply
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目录
基于PLC的恒压供水控制系统设计 ............................................................................................. 1
摘要 .................................................................................................................................................. 2
ABSTRACT .................................................................................................................................... 3
目录 .................................................................................................................................................. 4
一 绪论 ............................................................................................................................................ 8
1.1恒压供水问题的提出 ....................................................................................................... 8
1.2 国内外恒压供水控制系统的研究现状 .......................................................................... 9
1.3 本文的主要研究内容和结构 ........................................................................................ 10
二 变频恒压供水系统控制方案的分析及确定 .......................................................................... 12
2.1 变频恒压供水系统控制的理论分析 .................................................................................... 12
2.1.1 水泵电机的调速原理 ........................................................................................................ 12
2．2 供水系统控制方案的确定 .......................................................................................... 12
2.2.1 供水系统控制方案的分析 ................................................................................ 12
2.3 恒压供水的原理 .................................................................................................................... 13
2.4供水压力传感器的原理与选型 ..................................................................................... 14
2.4.1 压力传感器简介 ................................................................................................ 14
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2.4.2 压力传感器原理 ................................................................................................ 14
2.4.3 压力传感器的特性参数 .................................................................................... 16
2.4.4 压力传感器的选型 ............................................................................................ 17
2．5 供水压力信号的采集 ................................................................................................ 19
三 变频恒压供水系统的控制流程 .............................................................................................. 20
3.1变频恒压供水系统的组成及原理图 ............................................................................. 20
3.1.1 变频恒压供水系统的组成 ........................................................................................ 20
3.2变频恒压供水系统控制流程 ......................................................................................... 22
四 控制系统的硬件部分 .............................................................................................................. 25
4.1 系统主要硬件设备的选型 .................................................................................................... 25
4.1.1 PLC及其模块的选型 ......................................................................................... 25
4.1.2 变频器的选型 .................................................................................................... 26
4．1.3 水泵机组的选型 .............................................................................................. 26
4.2 硬件的PLC控制部分 .................................................................................................... 27
4．2.1 PLC的接线图 ................................................................................................... 27
4.2.2 PLC控制原理图 ................................................................................................. 28
4.2.3 PLC的程序的编制 ............................................................................................. 28
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