With the development of the economy, the requirement for the level of greening engineering is increasing. Meanwhile, in order to further solve problems such as shortage of water resources, energy, and increasing labor costs, more and more green engineering is adopting the automatic control irrigation system.
The commonly used automatic control systems can be divided into two categories: timed control irrigation systems, ET intelligent irrigation systems, and central computer control irrigation systems.
The timed control irrigation system takes the start time, length of time, and period of irrigation as control parameters to achieve automatic irrigation of the entire system.
The basic components include: controller, solenoid valve, and optional equipment such as soil moisture sensors, rainfall sensors, and frost sensors. The controller is the core of the system. Irrigation managers can set the start time, length of time, and period of irrigation in the program of the controller, and the controller sends signals to the solenoid valve through cables to turn on or turn off the irrigation system.
There are many types of controllers, including electromechanical and mixed circuit types, AC power supply types, and DC battery operation types. Their capacities range in size, with the smallest controller controlling only one solenoid valve, and the largest controller being able to control hundreds of solenoid valves. The solenoid valve is usually an AC 24-volt diaphragm valve connected to the controller via cables.
The solenoid valve has a delay when opening and closing, which can effectively prevent water hammer in the pipeline and protect the system's safety. Currently, most automatic control irrigation systems in China are timed control irrigation systems.
The ET intelligent irrigation system automatically converts meteorological variables related to plant water demand, such as temperature, relative humidity, rainfall, radiation, and wind speed, into digital information and transmits them to the timed controller through one-way transmission.
When used, only the information for each site (slope, crop type, soil type, nozzle type, etc.) needs to be set. There is no need to set the opening, running, and closing time for the controller. The entire system will automatically and accurately irrigate according to local meteorological conditions, soil characteristics, and crop types.
The central computer control irrigation system reflects meteorological variables related to plant water demand (such as temperature, relative humidity, rainfall, radiation, and wind speed) through an automatic electronic weather station to calculate the required amount of water for the day. The computer will then notify the relevant execution equipment to turn on or turn off a sub-irrigation system.
In the central computer control irrigation system, the above timed control irrigation system can be used as a subsystem. Currently, it has been widely used in irrigation systems for lawn and gardens, as well as golf courses, in many developed countries.