摘要

中央空调现已广泛的应用在各大商场、办公大厦等场所中，传统控制系统中在控制较适宜的温度的同时，却消耗了大量的能量。如今，人们越来越重视中央空调的舒适性和节能性，本文重点研究了中央空调控制系统，为舒适的生活工作环境及有效节能提供了技术条件。

本文主要介绍了中央空调的主要组成，分类以及工作原理；介绍了中央空调的控制技术的特点、结构和类型；分析了中央空调的控制要求，给出了其设计流程图，编写了PLC 梯形图，设计中央空调的PLC 控制系统，并进行调试运行；再利用WinCC flexible，设计中央空调的监控系统。整个调试运行结果验证了，上位机WinCC flexible和现场PLC 能实现互控，整个监控系统功能完善，操作简单。

该系统采用西门子的S7—300PLC作为主控制单元，利用传统 PID 控制算法，通过现场PLC控制水阀开度，保证系统根据实际负荷的情况调整流量，实现恒温控制，同时又可以节约大量能源。最后通过西门子Win CC flexible显示器实现人机界面的设计，人机界面包括系统工作流程图、设备启/停控制、状态显示、趋势曲线及报警显示等完善功能。最后使用 Win CC工控组态软件进行了系统的组态。

关键词：中央空调；PLC；控制系统

Abstract

Central air conditioning has been widely used in major shopping malls, office buildings and other places, the traditional control system in the control of suitable temperature at the same time, it consumes a lot of energy. Nowadays, people pay more and more attention to central air conditioning comfort and energy efficiency, this paper focuses on the research of central air conditioning unit control system, for comfortable living and working environment and effective energy-saving provide technical conditions.

This paper mainly introduces the main composition of central air-conditioning, classification and working principle. It introduces the control technology of central air conditioning the characteristics, structure and type. It analyzes the central air conditioning control requirements of someone hotel, gives the design flow chart, write PLC ladder diagram, the design of central air-conditioning and PLC control system, test and operation. The central air-conditioning monitoring system is designed. The debug operation results verified, PC-Win CC and on-site PLC can realize mutual control, the whole monitoring system has perfect-function and simple-operation.

The system adopts Siemens S7-300PLC as the main control unit, by using the traditional PID control algorithm, through the PLC control valve location, ensure the system according to the actual load adjusting flow, to achieve constant temperature control, but also can save a lot of energy. Siemens Win CC flexible display is realized through the man-machine interface design, Based on PLC and Win CC flexible Configuration the air-conditioning monitoring system is developed whose functions cover a wide range from display of working states of the system control of equipment start-to-stop processes display of trend curve to data and alarm display. finally using the Win CC configuration software for system configuration design.

Key words： Central air conditioning；PLC；control system