Design Of Low-cost Intelligent Monitor And Control System For The Greenhouse Environment

The population is much, the agricultural soil is little and the weather condition is bad in our country, in order to realize superior quality, efficient and high produce of farm crop, develop and research intelligent monitor and control system for the greenhouse environment is very necessary; the purchases ability of the agriculture customer is limited in our country, but intelligent monitor and control system for the greenhouse environment or controller products, which is existing in market, their cost is high, price is expensive, control decision is more simple and regulate ability to the greenhouse environment is limited. Aim at these problems, this thesis present and design a kind of low price, low cost and practical intelligent monitor and control system for the greenhouse environment.According to the condition, control characteristics and control method of environment factors such as temperature, humidity, light shine and carbon dioxide, which influence farm crop grow in greenhouse, the thesis put forward the project controlling these environment factors that is fit for this system. Considering the different request of the different customer, the monitor and control system for the greenhouse environment was designed for the four kinds of constituting mode. According to actual demand, the customer can choose the fit mode.Adopting MSP430F449 of ultra-low-power consumption microcontroller as a core, the general intelligent terminal and the intelligent temperature and humidity sensors was designed in the paper. The design and realization of the tasks, hardware, software and control algorithm of the intelligent terminal and the intelligent sensors is introduced with emphasis. In the aspect of hardware, the design thinking, the principle electric circuit and the anti-interference methods of every part of the system is introduced, and the total hardware principle diagram was given. Moreover, for realizing low cost of system, the cheap component was chosenpossibly under satisfying the design request. In the aspect of software, the admixture scheduler, which is triggered by time, was adopted when designed, and the reliability and the expansibility of the system is improved.It is another emphasis that RS-485 multiprocessor communication is designed in the thesis. Compared with several kinds of communication bus at present, and considered that the characteristics of RS-485 bus is cheap, the period of development is short, communication agreement is made freely, easy to expand and maintenance, RS-485 was chosen as the communication bus, the hardware of 485 communication interface was designed, serial communication agreement was defined, the principle and the method that RS-485 multiprocessor communication was realized by MSP430F449 microcontroller and VB, the communication program of PC and MCU designed, and the method of the correspondence anti- interference was given.Because it doesn't reach the effect anticipated, when the traditional PID control algorithm to control the temperature and the humidity in greenhouse adopted, fuzzy control algorithm to controlthe temperature and the humidity was adopted by the intelligent the temperature and humidity sensors of the system, and taking an example that fuzzy control is applied to reduce the temperature degree in greenhouse in summer, the design and the realization was described.Because the function of master computer renews continuously according to actual circumstance or customer's need, from the minimal function request by the monitor and control system, master computer PC was designed.According to the function of system designed, the thesis designed, installed and debugged the experiment device of the general intelligent terminal and the intelligent temperature and humidity sensor, and constituted the monitor and control system by 485 bus. Based on the device, lots of experiments prove that the system is right and viable.Finally, the thesis was summarized, the main work that the thesis completed was introduced, the main characteristics and the significance was explained, at the same time, the shortage and the improved idea was pointed out and the preparation was made forthe further research in future.