Study And Design Of Tunnel Greenhouse Environment And Drip Irrigation Control System Use P87C552 Microcontroller

Greenhouse is not only an important part of facility agriculture, but also one of the developing emphases of modern developing agriculture. The experience of the greenhouse management has proved that improving greenhouse automation can increase the efficiency of greenhouse production. The purchases ability of farmers is limited in our country, and the purchasable intelligent monitor and control system for the greenhouse environment are expensive and complicated. In this paper a control system with lower price was designed for greenhouse control and automatic irrigation.This system can monitor greenhouse environment using P87C552 SCM, and control the greenhouse ventilation device, solar protection device, and drip irrigation system in order to let temperature and humidity among setpoints.It mainly included environmental parameters measuring module, data processing module, fuzzy decision-making module, real-time controlling module, and system parameters setting module.The environmental parameters measuring module mainly measured temperature, humidity and illumination in the greenhouse. It gathered temperature and illumination by the AD590 and the silicon photocell sensor, then output relevant signal. HM1500 was selected as humidity sensor. After integration, sensors were checked and calibrated; data indicated that it met the need of greenhouse measurement.The data processing module included data storage, display and sound and light alarm. Serial interface chip AT24C256 was selected as data storage; parallell extending chip 8155 as data display and LED as time, temperature, humidity and illumination display respectively. When some environmental values exceeded the setting upper and lower limit or faults come out, control system would send out alarm by buzzer and LED.The fuzzy decision-making module consisted by fuzzy controller. Using error and its rate of temperature and humidity to be the input values of fuzzy controller, the opening angle of shading and window were output. Triangle had been adopted as subjection curve, and the system was designed and simulated by Matlab according to the fuzzy control rules.The real-time control module had adopted the photo-electricity isolation to drive relay in order to control shading, window and drip irrigation system. The chips of photo-electricity were selected TLP521-4 and TLP521-2; and relay JZC-23F.The system parameters pre-setting module consisted of temperature, humidity, illumination and time parameters setting.After installation, contrast experiments had been conducted between well-controlled greenhouse and designed system. It showed shading and windows control had the same time sequence almostly between each other, but time sequence was different between drip and spray irrigation systems.