一. Program overview
This program adopts Coolmay PLC all-in-one machine to automatically control the irrigation system. The controller model is Coolmay CX3G-34MT-12AD8DA-A0-A0-485/485. The main components require 10 solenoid valves and 2 frequency converters. 2 motors, 4 proportional valves, 2 pressure sensors, 4 liquid level sensors.
二. Technical effect
1. Solenoid valve control
The system uses 10 solenoid valves, which can be controlled manually or automatically.
In the automatic control mode, an automatic process includes 10 steps, the user can specify how many steps to use, as well as the solenoid valve and power-on time of each step, after pressing the automatic start, the system will execute from the first step of the process to use the last step.
In the manual control mode, the switch of the solenoid valve can be directly controlled, and the switch status of the solenoid valve can also be monitored through the HMI on the all-in-one machine.
2. Water pump control
Manual and automatic controls are required. After the automatic control is turned on, it keeps at a set pressure value. If one or more valves are opened and the pipeline pressure drops, the system will automatically increase the operating frequency of the inverter, and the motor will speed up to maintain the pipeline pressure at the set value. The pressure value, so that the pressure is kept in a constant range, and the outlet pressure of each pipe is kept constant.
Regarding the operation of the water pump, when the valve is closed, the pressure in the pipeline will stop after it rises to the set value, and when it is lower than the pipeline pressure, the system will automatically adjust the pressure to maintain the pressure at the set value. When the pipeline pressure exceeds the alarm set value, the system will alarm to indicate that the pressure is too high, and when it is lower than the alarm to indicate that the pressure is too low, and stop to protect the motor. When the motor is running at low frequency for a long time, the inverter will automatically stop running after the motor reaches the low frequency stop time to protect the motor.
3. Fertilization control
The fertilization control part consists of 4 proportional valves, a water pump and 4 liquid level gauges. During the fertilization process, put the fertilizer in the container to dissolve, then put the four pipes into the container, and set the ratio of the four fertilizers on the HMI, the controller will adjust the opening of the proportional valve through calculation, and control the four pipes. The fertilizers are mixed in proportion.In the process of fertilization control, it is also necessary to set the control range of the pressure of the pipeline. After opening, through the setting and operation of the system and PID adjustment, the fertilization pressure can be maintained within a constant pressure range, and the pressure of the fertilization pipeline needs to be higher than that of the water pump pipeline. The pressure is high, so as to ensure the normal delivery of fertilizer.
Fertilization is turned on and off by a manual switch. When the pressure exceeds the set pressure alarm value, the system will start to alarm. When the liquid level of the fertilizer tank is too low, the system will alarm and remind the staff to add material, or pay attention to the operation of the system. If the temperature is too low, the system will automatically stop the operation of the fat pumping motor and send out an alarm.
4. PID control
Constant pressure water supply. When opening different numbers of solenoid valves, it is necessary to keep the water pressure constant, so as to avoid that the water pressure becomes smaller due to the increase of the water output, and the irrigation does not reach the set irrigation range. Therefore, the operating frequency of the inverter must be changed through the PID adjustment operation. Thereby changing the running speed of the water pump motor to maintain the water supply pressure within a constant range.
Constant pressure fertilizer supply. When transporting fertilizer, the pressure of the fertilizer delivery pipeline must be greater than the pressure of the water supply pipeline. Through the PID parameter setting adjustment, the pressure of the fertilizer delivery pipeline is controlled within a constant set value range to maintain the normal operation of fertilization.
三．Solution advantage
1. Construct a complete intelligent irrigation system to realize quantitative irrigation, regular irrigation and on-demand irrigation;
2. Establish an intelligent management monitoring platform, the control system can help users automatically and continuously detect the actual working conditions of each irrigation area, and display relevant data on the touch screen in the all-in-one machine;
3.Convenient operation, stable performance and low maintenance cost.
四. Program Summary
Coolmay PLC all-in-one machine is used in the design of water-saving irrigation control engineering, which can simplify the hardware structure, improve reliability, increase flexibility, and is suitable for various environmental conditions. It is an excellent solution for the automation of agricultural irrigation systems, and has broad application prospects and use value.