agricultural irrigation system

What is an agricultural irrigation system？



Agricultural irrigation system is a comprehensive measure to utilize precipitation and irrigation water efficiently according to the law of crop water demand and local water supply conditions to obtain the best economic, social and ecological environmental benefits of agriculture. That is, water saving irrigation includes comprehensive measures such as technology, management and economy, and is not a single means.



Intelligent agricultural irrigation system is also called intelligent agricultural Internet of things fine agricultural automation system, which is a set of solutions to save water under the premise of ensuring the water demand of agricultural crops. The intelligent agricultural irrigation system simply means that agricultural irrigation does not need human control, and the system can automatically sense when to irrigate and how long it will be; the intelligent agricultural irrigation system can automatically turn on irrigation or automatically shut down irrigation; it can increase the amount of irrigation when the soil is too dry and reduce the amount of irrigation when it is too wet.



Working principle of agricultural irrigation system:



When the agricultural irrigation system works, the humidity sensor collects the dry humidity signal in the soil, and the detected humidity signal is converted through a/d module, and the standard current analog signal is converted into the humidity digital signal and input to the programmable controller. The programmable controller preset 50% - 60% RH as the standard humidity value. Compared with 50% - 60% RH, the actual measured humidity signal can be divided into three situations: in this range, it is beyond this range and less than this range.



The PLC transmits the control signal to the frequency converter. The frequency converter adjusts the motor speed according to the humidity value. The motor drives the pump to pump water from the water source. When irrigation is needed, the Solenoid Valve will automatically open. The main pipe and branch pipe are used as the water conveyance nozzle, and the nozzle will rotate automatically at the rotation angle of each self. The solenoid valve will close automatically at the end of irrigation. In order to avoid that the nozzle far from the water source cannot be supplied with enough pressure, a pressure gauge is installed on one side of the solenoid valve to ensure that the water pressure of each nozzle meets the set range of spray irrigation, and avoid the phenomenon that the range of the nozzle is reduced due to the lack of water pressure. The whole system coordinated work to realize the intelligent control of lawn irrigation.



In conclusion, to realize intelligent irrigation, the system needs programmable controller, sensor, a/d module, frequency converter, motor, water pump, solenoid valve, pipe network and nozzle, etc.



① PLC: responsible for issuing and receiving various operation program instructions, and is the central part of the whole control system.



② Sensor: because the design time is relatively short, the influence of temperature on irrigation is ignored, so no temperature sensor is used, only soil humidity sensor is used. The moisture signal in soil is collected by sensor to determine whether irrigation is needed.



③ A/d module: because the PLC can not receive analog signal, it is necessary to convert the voltage or current signal of the sensor into digital signal.



④ Frequency converter: adjust the spray irrigation flow by changing the motor speed to achieve the purpose of water saving.



⑤ Motor and water pump: the motor drives the pump to pump water from the water source, providing certain pressure for the sprinkler system.



⑥ Solenoid valve: control whether the spray irrigation of the nozzle is not.



⑦ Nozzle: achieve uniform spraying, easy to fully absorb.



⑧ Pipe network: the pipe for water delivery in irrigation system.



What are the functional designs of agricultural irrigation system?

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1. To realize the above functions, the intelligent agricultural irrigation system should make full use of the control function of the programmable controller. In order to realize the function of automatic sensing soil humidity, the system must have soil humidity sensor. To realize the regulation of irrigation water quantity more and less, frequency converter must be provided. The standard humidity is set in the PLC from 50% to 60% RH in advance. The humidity analog signal collected by the sensor is converted into digital signal by a/d module.



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2. In view of the low water use coefficient of irrigation, an intelligent irrigation control system based on embedded is proposed. The information of crop water demand in irrigation area is collected by wireless sensor network, and sent to the main control center by the gateway node. The central host determines the irrigation status and calculates the irrigation amount according to the information, and controls the irrigation equipment to realize intelligent irrigation; relying on the Internet administrator has the right to manage the system in a long-range way, which meets the needs of large-scale irrigation. According to the observation in the demonstration area, the irrigation water use coefficient is increased from 0.6 to 0.9. The system combines wireless sensor, computing and network communication technology, and solves the key technical problems that need to be solved in precision agriculture.



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3. Intelligent agricultural irrigation system involves sensor technology, automatic control technology, computer technology, wireless communication technology and other high-tech. the application of these new technologies has laid an important foundation for the transformation of agriculture from traditional labor-intensive to technology intensive.



4. Intelligent agricultural irrigation system can optimize water consumption according to plant and soil types and light quantity, and monitor soil moisture after rain. There is a research reality. Compared with traditional irrigation system, the cost of intelligent agricultural irrigation system is similar, but it can save 16 to 30% water.



What are the design characteristics of agricultural irrigation system

1. The system is modular and hierarchical design, which can improve efficiency, increase maintainability and facilitate expansion;



2. Flexible hardware configuration, users can upgrade and replace the controlled hardware equipment without changing software;



3. The man-machine interface is friendly, and the unattended irrigation process can be realized, the working intensity of personnel will be reduced and the irrigation efficiency can be improved;



4. The ability of anti electromagnetic interference is strong, and the system can operate reliably in the harsh environment of strong electromagnetic interference in the field;



5. The automatic fault detection function improves the robustness of the system, and the layout of various equipment requires beautiful appearance.



Working principle of agricultural irrigation system

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What are the nine functions of the agricultural irrigation system?

In order to save water for sprinkler irrigation and realize intelligent control, the irrigation system must have the following functions:



1. Data acquisition function: it can receive the analog quantity collected by soil humidity sensor. The processing of analog signal is to transform analog signal into digital signal (a/d conversion).



2. Control function: it has the function of timing control and cycle control, and the user can flexibly select the control mode according to the needs.



① Automatic control function: the programmable controller compares the humidity signal detected by the sensor with the preset standard humidity range value through the program. If the humidity value detected exceeds the set humidity value, (if it is lower than the setting value, the motor speed will be increased, and the motor speed will be reduced if it is higher than the setting value), then the motor speed will be adjusted automatically for irrigation operation.



② Timing control function: the system can set the on and off time for the solenoid valve. When the humidity value of irrigation reaches the set humidity value, the motor will stop irrigation automatically.



③ Cycle control function: the user pre programmed the control program in the PLC, set the start time, end time, irrigation time and stop time respectively, and the system automatically circulates irrigation according to the set time.



Variable speed function: compared with the moisture value of 50% - 60% RH which is the most suitable for lawn growth, the current measured soil humidity value can be divided into three results: greater than, equal to and less than three results, which can be divided into three states: high humidity, medium humidity and low humidity. The control panel is displayed as three indicators: high humidity, medium humidity and low humidity. The frequency converter automatically adjusts the motor speed according to the three states of soil humidity. The motor is equipped with three kinds of rotation speed, namely high speed, medium speed and low speed, which correspond to three indicator lights, namely high speed, medium speed and low speed respectively.



4. Automatic rotation and stop function: the control system automatically starts the spray irrigation according to the dry humidity of the soil, and controls the motor to rotate at the required speed. The sprinkler shall spray for 5 minutes, stop for 2 minutes, and then automatically stop running after spraying for 5 minutes.



5. motor overload protection function: when the motor is overloaded, the motor will stop rotating immediately, the irrigation process will be stopped, and the fault indicator will flash to alarm, and the overload will be automatically restored to operation after the overload is eliminated.



6. Automatic stop in rainy days: the switch value of humidity sensor is used as input signal of a programmable controller to realize the function of controlling related programs.



7. Power saving function: timing controller normally timing when power is off, so it is used as power control of programmable controller. Within the time limit of timing irrigation control, the timer will turn on the power supply of the PLC, and the PLC shall turn on the power supply of each control equipment according to the pre programmed program, and adjust the execution of the program at any time according to the change of input signal. In the non system working time, timer automatically disconnect the power supply of PLC, which not only reduces the power consumption of the system but also extends the service life of the equipment.



8. Emergency stop function: in case of emergency accident, press the emergency stop button, the motor will stop running immediately, the valve will be closed and the sprinkler will stop irrigation.



9. Automatic fault detection function: when the irrigation system fails, such as water pipe rupture (water pressure is zero), sensor failure, motor fault, frequency converter fault, solenoid valve fault, etc., the water pump stops running immediately, the solenoid valve is closed, the fault alarm lamp flashes and the alarm siren sounds. The operator can press the "mute" button to cancel the bell, but the fault indicator is still flashing, and the fault indicator will not stop flashing until the fault is eliminated.