Study And Design Of Tea Gardon Constant Pressure Spray Irrigation Control System Based On PLC

The importance of automatic technology in irrigation management is discussed, the present situation and existing problems of water saving irrigation controller at home and abroad are introduced in detail and the trends for further research are also discussed.According to the requirement of water supply in student apartment d istrict of,a set of automatic system of constant pressure water supply by using variable frequency and remote monitoring and controlling which is composed of PLC, transducer, pressure sensor, pumps and electro-motors, computer and device of communication is designed to that end. This set of system has the functions like automatic constant pressure operation by using variable frequency,automatic work frequency operation, and the function of long-range controlby hand and the on the spot control by hand etc. The system has solved efficiently the problem existing in the tra- itional way of water supply, which has various supplementary functions to strengthen the reliability. The system has an organic combination with computer and Promotes the systematic overall performance.Based on the lift and pipe characteristics of a water supply system the paper analyses the mechanism of energy saving that the way of water supply by using the method of variable velocity variable frequency is superior to the traditional way of constant pressure water supply controlled by valve.Setting up in advance the parameter of the PID modual built in the transducer, a system of closed circuit using the feedback of hydraulic pressure of far biography pressure table has formed. According to the change of water consumption, with PID,in the sphere of whole rate of flow, combining the constant regulation of the pump of frequency con- version with the work frequency pump grade regulation, the system of closed circuit can realize the constant pressure water supply and save energy efficiently.This paper the control strategy was put forward that two pumps were controlled in grades and freqeequency conversion by turns, and analyses the conversion condition and the various states of water supply of the two pumps way of water supply . At some time, analyses the switch process and the problem of agenerator from variable frequency operation mode to work frequenay operation mode, providing specific cut-over methods and control circuits.By researching the communication agreement between the computer and PLC,this paper has finished setting up the communication between upper and lower computer , and also has developed computer monitoring program to realize the long-range monitoring and fault reporting for water supply system through communication modular.The paper on the basis of analyses the inverters jamming source ofcontrol system, from two aspects of handware and software, advanced some anti-interference technology measures ,the reliability and continuity of the system have strengthened.