摘要：本毕业设计介绍了节能、环保和恒压型供水控制系统。落实节能科技的策略，阐述了基于STEPT7恒压供水系统在楼宇供水中的应用。采用PLC现代控制技术和变频器调速恒压控制技术，介绍了基于STEP7恒压供水系统的工作原理。详述恒压供水系统的特点，进行了PLC控制系统的硬件和软件设计。基于STEPT7恒压供水系统基本控制策略是：以变频器调速装置与可编程控制器(PLC)构成控制基础，优化泵组的调速控制方式，实现供水压力的闭环控制，达到了恒压供水的目标，凸现了系统控制方式的优势。系统的控制对象为泵组出口管的压力，将反馈的实际出口管的压力与系统设定值进行比较，其差值输入计算机处理后，发出控制指令，控制泵组的运行台数和电机的运行转数，保证出口管的压力处于恒值，实现了恒压供水的目标。31991
毕业论文关键词：可编程控制器（PLC）；变频器；PID控制；恒压供水 
The control system of constant pressure water-supply based on STEP7
Abstract：The paper design of the energy conservation, environmental protection and the constant pressure water-supply control system are presented. Carrying out the strategy of energy saving technology, expounds the constant pressure water-supply system in the application of the building water-supply based on STEP7.Using the modern control technology of PLC and frequency converter speed regulation constant pressure control technology, and the working principle of constant pressure water -supply system based on STEP7 are introduced. In detail the characteristics of constant pressure water-supply system, design the hardware and software of PLC control system. The basic control strategy based on STEPT7 is: constant pressure water-supply system with frequency inverter speed control device and a programmable controller (PLC) based control, optimization of pump speed control mode, realization of water supply pressure closed-loop control, to achieve the goal of constant pressure water supply, highlight the advantages of the system control mode. System control object for the pump outlet pipe, the pressure of the feedback of actual outlet pipe pressure and system set data comparison, the difference between input after computer processing, sends out control instructions, control the operation of the pump group sets and motor operation of revolution, to ensure that the outlet pipe pressure at a constant value, to achieve the goal of constant pressure water supply.
Keywords: Programmable；controller (PLC) ；The inverter ；PID control ；Constant pressure water-supply
目  录
1. 绪论    1
1.1 选题的意义和背景    1
1.2 恒压供水系统简介    1
1.3 本设计主要工作    2
2. 恒压供水的基本构成    3
2.1 基本概述    3
2.2 设计模型    3
2.3 控制目标    3
2.4 变频恒压控制系统设计    4
3. 变频器和压力传感器的选型    5
3.1 变频器的介绍    5
3.2 变频器的基本结构    5
3.3 变频器的分类    6
3.4 变频器的选型    7
3.4.1 变频器的控制方式    7
3.4.2 变频器容量的选择    8
3.5 压力传感器    10
4. PID控制设计    11
4.1 PID控制原理    11
4.2 PID控制器的选型    12
5. 硬件设计    13
5.1 PLC控制器的概述    13
5.2 PLC型号的选择    13
5.3 PLC的CPU选择    14
5.4 I/O模块选择    14
5.5 电气系统控制原理    17 PLC基于STEP7恒压供水控制系统设计+梯形图:http://www.youerw.com/zidonghua/lunwen_28364.html