基于PLC的温度控制系统设计毕业论文.doc

通过对温室控制对象和温室环境的特点的分析,确定了控制系统的结构和控制方案,本文设计了以 PLC 为下位机,以装有组态王软件的 PC 机为上位机的分布式智能温室监控系统。硬件主要包括 PLC 及其特殊功能模块、各种传感器电路、电源和执行部件,软件主要是组态王软件和三菱 PLC 编程软件 GX Works。
控制系统有手动控制和自动控制两种控制方式。在自动控制模式下,下位机PLC 通过传感器采集环境参数,并与用户设定的环境参数上限下限比较,控制相应执行部件启停,调节温室环境参数。在手动控制模式下,用户根据需要控制上位机组态王手动画面的模拟开关,控制 PLC 发出开关指令控制对应执行机构,对温室环境进行调节。上位机 PC 的组态软件与下位机 PLC 通信,完成人机交互的功能。通过组态王实时显示下位机采集的环境参数当前值、执行部件状态、故障报警等,同时可以进行趋势曲线查看、数据库操作等。另外用户设定环境参数、手动自动控制切换、手动控制模式下控制模拟开关也在组态王上进行。
通过系统的测试实验,智能温室监控系统基本达到了预期的设计目标,但是还需要继续完善才能运用于实际温室。
关键词:智能温室,PLC,组态王ABSTRACT
ABSTRACT
As the biggest agricultural country in the world, China's agricultural production Hasa pivotal position in national the improvement of living standards,demand for green vegetables are growing,therefore our country agriculture overdevelopment extensive to intensive has e an inevitable trend,and as one of the importancy of the developing,agricultural facilities are receiving much more attention. Crop growth is mainly affected by temperature, humidity, light intensity, carbon concentration's and other environmental factors, so the purpose of building Intelligence is to automatically control these environmental parameters.
Through the analysis of controlled object and environmental quality greenhorn,we determine the structure of the control system and control programs. In this paper, we design a distributed intelligent greenhouse control system,which ha puter-programmable logic controller and puter-a personal with King. Hardware mainly includes the PLC and its special function module, all kinds of sensor circuit, power supply and execution unit;software maidenlinesses King and Mitsubishi PLC programming software-GX Developer.
The control system has two control modes-manual control and automatic control. In the automatic control mode, puter-PLC collected environmental parameter sensors pared with the minimum maximum environmental parameters which are set by the users to control the start and stop of the corresponding execution unit a