| The function and structure design of multi-span plastic greenhouse in East China has reached the international excellent level, but the facility of environment monitor and control system has not been current yet. The main task of the paper is to research the optimal design of intelligent monitor and control system, and the task roots in the item of the optimal design of structure and control facilities for multi-span plastic greenhouse in East China (Transform item of technological and fatal production during ten-five period in China).An ADuC812-based monitor and control system for the structure of multi-span plastic greenhouse is presented, and related hardware and software design methods are given. The ADuC812 is a fully integrated 12-bit data acquisition system including eight analog input channels. The system used the technology of sensor, automatic acquisition, communication and computer to collect greenhouse environment factors of temperature, humidity, light intensity and CO2 concentration in real time. The general idea of the system design is as followed. The sensors transform the not-electric signals to electric signals, and which are sent to the microprocessor ADuC812. The digital signals dealed with ADuC812 are sent to the LED, and compared with the digits which are set by user's experience. If one or more of the detection values are beyond the limited the light and sound alarm case will be given, then the system transfers control signals from the controller to the actuators. The actuators are automatically controlled to reach the aim of integration of multi-monitor and multi-control. Meanwhile the microprocessor connects with personal computer through the bus of RS-485 to retake the test data stored in memory and put in the database of the management control system. The user interface of computer is designed based on LabVIEW(National Instruments), using the technology of database to analyze the digitals, display as well as save and print some kind of curves and tables. And that realize the accurate and intelligent monitor and control of temperature, humidity, light and CO2 concentration in greenhouse, which is the foundation of the industrialization.The main study includes the design of hardware and software of the system, the concrete content is as followed:(1) Based on the microprocessor ADuC812, the multi-parameter monitor system of greenhouse was developed, and the parameters can be automatically detected. The system composed of outside weather station, sensor, main controller, microprocessor and printer is created involved with the subjects of information, electronics, detection technology and bio-environment etc.(2) There is a controller in every district of greenhouse. It can modulatethe facility in the greenhouse such as the roof and side ventilation-windows, shade curtains, sprayer, heater and circumfluent fans etc, and then complete the function of decrease or increase the temperature, humidity, light intensity and C02 concentration in the greenhouse.(3) The low layer communicates with top layer exchanging the data and control state by the RS-485 in real time.(4) The development of the computer system software based on LabVIEW, and the function of real time detecting, data presentation, graphical trendline displaying, digital data analysis, storage, and printing is achieved. The software include the following ten modules: communication module, real time detect module, digital analysis module, system parameter setting module, intelligent control module, database management module, controlled signal output module, printing module, real time alarm module and help module.(5) The system has manual control and auto-control and which to choose depends on the users. The auto-control system has the control strategy of PID control, fuzzy control and neural networks, and which strategy to be chosen is also decided by user.Tests showed this system was distinguished by its high precision, stable performance, simple hardware structure, and miniature volume and... |
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