The Study And Development Of Greenhouse Environment Computer Controlling System

Our country is a traditional large agricultural country.Agriculture development has a series of limitation, such as overpopulation, limited soil and water, low science and technology level farm produce.In order to solve these, we should develop modern efficient agriculture with high quality produce. Facility agriculture which uses greenhouse as representative is one aspect of modern agricultural development fields. Therefore, environment control is an important aspect of greenhouse plant.In 21st century,Facility agriculture is the most vigorous industry. Greenhouse environment control technology has a rapid development in recently 50 years. Developed countries has owned very advanced equipments and means in environment control. Environment factors such as illumination, temperature, humidity and atmosphere are all real time control. But their equipments mainly depend on large quantity of energy waste.Furthermore their control focus does not match our continental climate. Developed countries has mighty economic power and enough energy, while our country is a developing one. Foreign equipments do not all fit the situation of our country. It's necessary to develop low cost and good quality greenhouse environment control system at home.The control system consists of one PC as Upper computer, eight PLC as lower computer. On distribution of systemic function, upper computer and lower computer can parallel work. It increases the dependability of the system.PC has RS-495 serial interface commonly.Software is the center of control system. It contains two parts:upper computer software and lower computer software.The former adopts VC++6.0, Windows98 as operation platform. The latter adopts SIMATIC S7-200 WINCC4.0 language. Lower computer software is composed of some submodels:initialization model,LCD display model,data transmission/receiving model,data sampling disposal model . Upper computer software is composed of communication model,data managing model,parameter setting model and data real time detecting model.