毕业设计 [论文]
题目：基于PLC的变频调速恒压供
水系统设计
系别：电气与电子工程系
专业：电气自动化技术
河南城建学院毕业设计摘要
摘要
在城市化进程迅速的今天，城市的居住形式主要是生活小区，那么小区供水系统的建设就显得尤为重要。而且随着城市用水量不断增加，对供水系统的建设提出了更高的要求。供水的经济性、可靠性、稳定性直接影响到小区住户的正常生活和工作。本系统是针对居民生活用水而设计的一套由变频器、PLC、水泵机组等设备组成的自动变频恒压供水控制系统。系统将PLC、变频器、相应的传感器和执行机构有机地结合起来，并发挥各自优势，能够最大程度满足需要，具有运行稳定、操作简单和高效节能等特点。该系统对变频器内置PID模块参数进行预置，通过压力传感器对水压的反馈构成闭环控制系统；
PID模块根据用水量的变化调节水泵的输出流量，实现恒压供水，并达到有效节能的目的。系统采用变频调速方式自动调节水泵电机转速或加、减泵。改变以往“先启后停”方式，自动完成泵组软启动及无冲击切换，使水压平稳过渡。变频器故障时系统仍可运行，保证不间断供水。系统断电恢复后可自启动。采用硬件/软件备用及钟控功能，使各泵进行轮休，延长了设备的机械使用寿命。
首先介绍采取变频调速方式实现恒压供水相对于传统的阀门控制恒压供水方式的节能原理；其次，对水泵机组的各种供水状态及转换的条件、水泵由变频转工频运行方式的切换过程进行分析，着重研究并提出了基于PLC和变频器的恒压供水系统的方案，并给出了硬件设计和PLC控制程序设计。
关键词：PLC；变频调速；恒压供水
河南城建学院毕业设计摘要
ABSTRACT
In today's rapid urbanization, urban living is mainly living quarters, then the construction of residential water supply system is particularly important. And with the growing urban water demand, water supply systems, the proposed higher requirements. Economics of water supply, reliability and stability to the district residents directly affected the normal life and work. PLC, water pump and other
equipment consisting of automatic constant pressure water supply control system. System PLC, frequency converter, the corresponding sensors and actuators together organically, and play their respective advantages, the control system easy to operate, not only to the greatest extent to meet the needs of stability and security of its operating performance, simple and convenient mode of operation , and the complete and thoughtful features, will make water saving water, saving, labor saving, high efficiency high-quality final run, reliable, energy-saving purposes. This paper introduces the way to achieve frequency control constant pressure water supply valve control compared to conventional energy-saving principle of constant pressure water supply. Converter built-in PID module on the preset parameters, using hydraulic pressure sensor feedback, closed loop system. According to changes in water consumption, to PID regulation mode, by adjusting the pump output flow, constant pressure water supply and efficient energy. Then it analyzes the state of pump units and conversion of various water conditions, analysis of the pump frequency by the frequency change operating mode of the switch process. Important parts of functional analysis, focusing on research and put forward based on PLC and frequency constant pressure water supply system program, were given control of the hardware design and PLC programming.
Keywords: PLC; frequency control; constant pressure water supply
目录
1 绪论 (1)
1.1 研究背景 (1)
2 系统的理论分析及方案的确定 (4)
2.1 调速方式的比较与选择 (4)
2.2 控制系统方案 (6)
2.3 供水系统的控制流程 (8)
2.4 变频恒压供水系统中加减水泵的条件分析 (10)
3 变频恒压供水系统的硬件设计 (11)
3.1 PLC选型及接线 (11)
变频器恒压供水3.1.1 PLC选型 (11)
3.1.2 PLC的接线及I/O分配 (14)
3.2 水泵机组选型 (15)
3.3 变频器选型及接线 (16)
3.3.1 变频器选型 (16)
3.3.2 变频器的接线 (19)
3.4 PID调节器 (20)
3.5 压力传感器 (22)
3.6 系统主电路设计 (22)
4 系统软件设计 (24)
4.1 PLC控制 (24)
4.1.1 PLC程序流程图 (24)
4.1.2 手动运行 (25)
4.1.3 自动运行 (25)
4.2 编程及介绍 (26)
4.2.1 总程序的顺序功能图 (26)
4.2.2 自动运行顺序功能图 (26)
4.2.3 手动模式顺序功能图 (27)
4.2.4 系统程序梯形图设计 (28)
5 总结与致谢 (29)
参考文献 (30)
附录A 系统硬件总图 (2)
附录B 系统梯形图 (3)