Greenhouse Automatic Control System Design

AbstractClimate conditions, control emPhases of auomatic control greenhousesintroduced from abroad are different from these in home and the introducingand production cost of them is so high,so it is difficult to pOPularize and usecosmically .At presed, in greenhouses designed and built in home itself, thedegree of environment control and modern management of most of them is solow,so thcy cannot satisfy crops' demand for high production and planing alIthe year; some can only cap oot cofltrol on partial environrnent factorswithout considering mutua1 affect and couPling of them in the process ofcontrol: some still need manual cOfltrol: so these factors greatly restrictexertion of economic benefit of greenhouses. Changing traditional modes ofcontrOl, practicing comPuter monitoring and establishing greenhouseautomatic monitoring system accord with the situation of China haveimPortan meaning for quickening modem degree of greenhouse productionin our country and increasing benefit of greenhouses.Based on summarizing formers' researches, the paPer analyzesenvironmental parameters, the integrative control proPerty of greenhousesystems and the control process Which is a nonlineap delay and comPlicatedsystem: Based on analyzing modes of current greenhouse monitoringsystems and properties of single-chip microcomputers, a practical alltomaticmonitoring system for greenhouse environment is designed which can realizethe monitoring of every parameter in greenhouse environmeflt bysynthetically using sensor technology fuZZy control theory communicationtechnology and microcomputer technologyThe system hardware is comPosed of tWo parts: a lower-level and ahigher-level computer. The higher-level comPuter is a PC microcomPuter,which is the headquarter of the system and finishes the unified managementand control of a greenhouse by way of COM port RS-232 connecting with thelower-level compllter. In monitoring environmellt, the system can finishmonitoring for this nonlinear and delay system and realize crops' demand forgreenhouse environment by using fuZZy control theory and technology .Thecentral component of the lower-level comPuter is 8098 single-chipmicrocomputer of MCS-96 series, which is used to collect, pretreat, controIand communicate with the higher-level computer.The system software consists of two parts .The higher-level software is developed by VB and composed of seven modules of setting system parameters, demarcating sensors, ascertaining fuzzy control table, connecting and monitoring real-time data, recurring to history data and help, and each module has certain function and each other is independent from others. The lower-level software is developed by 8098 assemble language and composed of six modules of a main program, a sending and interrupting service program, a receiving and interrupting service program, ascertaining a sampling cycle, connecting data and pretreating data. Simulative experiment shows that the whole system is convenient to operate, high efficient, easy to expand, has better adaptability and universal property and establishes certain base for realizing control system design with many factors in greenhouse environment.