基于PLC的恒压供水系统的设计

基于PLC的恒压供水系统的设计

文档编号:DQ311 文档字数:18644,页数:41

摘要
本设计根据楼宇供水要求，设计了一套由PLC、变频器压力变送器、多台水泵机组、计算机、通信模块等主要设备构成的自动/手动一体的变频恒压供水系统，具有全自动变频恒压运行、自动工频运行、现场手动控制等功能。
通过对变频器内置PID模块参数的预置，利用压力变送器的水压反馈量，构成闭环系统，根据用水量的变化，采取PID调节方式，在全流量范围内利用变频泵的连续调节和工频泵的分级调节相结合，实现恒压供水且有效节能。
本设计论述了采用多泵并联供水方案的合理性，分析了多泵供水方式的各种供水状态及转换条件，分析了电机由变频转工频运行方式的切换过程，给出了实现有效状态循环转换控制的电气设计方案和PLC控制程序设计方案。通过计算机和PLC之间通信协议，完成了上、下位机的通信设置，给出了计算机监控程序，通过通信模块实现了对供水系统的远程监控。

关键词: 恒压供水, PLC, 变频控制

Abstract
The design of water under the building requirements, design a set by the PLC, transducer pressure transmitter, multiple pump units, computers, communications equipment modules and other major form of automatic / manual one constant pressure water supply system with automatic frequency constant pressure operation, automatic frequency operation, on-site manual control functions.
Through the converter built-in preset parameters of PID modules, use the amount of pressure transducer pressure feedback, closed loop system, according to changes in water consumption, to PID regulation mode, the entire flow range of continuous adjustment using variable frequency pump and classification of the pump frequency of a combination of constant pressure water supply and effective energy conservation.
Discusses the design of parallel multi-pump water supply scheme is reasonable, of the multi-mode pump water water supplies status and conversion conditions, analysis of changing the motor from the inverter frequency during the switchover operation mode is given to achieve an effective state cycle conversion of electrical control design and PLC control program design. Through the communication protocol between the computer and the PLC has completed, the lower computer communications settings, given the computer monitor, through the communication module for remote monitoring of water supply systems.

Keywords: Water Supply, PLC, Frequency Control

目录
摘要Ⅰ
1 前言…………………………………………….…………………………………1
2 系统方案的介绍……………………………………………………2
2.1 变频恒压供水的理论分析…………………………………………………………….2
2.1.1 变频恒压供水的节能原理……………………………………………….…….2
2.1.2 变频恒压供水的理论分析……………………………………………………4
2.1.3 变频恒压供水的数学模型……………………………………………….…….5
   2.2 变频恒压供水系统的方案介绍………………………………………….….6
.   2.1.2 变频恒压供水系统的方案…………………………………………….….6
   2.2.2 供水系统中水泵切换分析………………………………………………….9
3 变频恒压供水系统的硬件组成………………………………………………10
3.1 系统主要配置……………………………………………………………….….10
3.1.1 水泵机组的介绍……………………………………………………….10
3.1.2 变频器的介绍………………………………………………………………11
3.1.3 PLC的介绍……………………………………………………………….12
3.1.4 压力变送器的介绍……………………………………………………….13
3.2 PLC的I/O端口设置…………………………………………………………………13
3.3 变频器接线…………………………………………………………16
3.4 系统主电路的设计………………………………………………16
3.5 系统控制电路的设计.18
4 变频恒压供水系统的软件设计.20
4.1 系统水泵运行状态……………………………….………….20
4.2 系统控制程序的设计21
4.3 恒压供水的PID调节过程分析与PID向导设置.23
       4.3.1 恒压供水的PID调节过程分析23
    4.3.2 PID向导设置.23
4.4 PLC的程序执行25
   4.5 可靠性分析……………………………………………………………………32
4.6 变频恒压供水系统的远程监控33
5 总结………………………………………………………………….….35
致谢………………………………………………………………………36
参考文献………………………………………….………………………………… .37

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