Hardware
1. PLC
controller: Coolmay CX3G-34MT-12AD8DA-A0-A0-485/485
2. Main
components: 10 solenoid valves, 2 inverters, 2 motors, 4 proportional valves, 2
pressure sensors, 4 liquid level sensors
3. Other
components
Solenoid
valve control
This system uses 10 solenoid valves, which
can be controlled manually or automatically.
l Automatic
control
The process includes 10 steps. You can
specify how many steps to use, and you can specify the solenoid valve and
power-on time of each step. After pressing the automatic-start button, the
process will start from the first step of the process to the last step.
l Manual
control
Manual control mode can directly control the
switch of the solenoid valve, and can also monitor the switch state of the solenoid
valve from the HMI, and easily monitor the status of each solenoid.
Water
pump control
Manual and automatic control.
After the automatic opening, it has been
maintained at a set pressure. If one or more valves are opened and the pipeline
pressure is reduced, the system will automatically increase the operating
frequency of the inverter, and the motor will accelerate to maintain the
pipeline pressure at the set pressure. This keeps the pressure in a constant
range and keeps the pressure at the outlet of each pipe constant.
The
water pump is running. When the valve is closed, the pressure in the pipeline
will rise to the set point, and it will stop. When the pressure 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, it will prompt a high pressure alarm. When the pipeline
pressure is lower than the low-pressure alarm set value, it will prompt a low
pressure alarm and stop the motor to protect the motor. When the motor is
running at low frequency for a long time, after the motor reaches the low-frequency
stop time, the inverter automatically stops running to protect the motor.
Fertilization
control
The fertilization control part is composed of
4 proportional valves, a water pump, and 4 level gauges. During fertilization,
the fertilizer is placed in a container for dissolution, four pipes are put
into the container, and the four fertilizer levels are set on the HMI
Proportion, the controller adjusts the opening of the proportional valve
through calculation, and controls the four fertilizers to be mixed in
proportion. During the fertilization control process, the pressure of the
pipeline also needs to be controlled within the set range. After opening, the
system is set and calculated. The fertilization pressure is maintained in a
constant pressure range through PID adjustment, and the pressure of the
fertilization pipeline needs to be higher than the pressure of the water pump
pipeline, 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 setting, the
system starts to alarm. When the level of the fertilizer bucket is too low, the
system alarms to remind the staff to feed or pay attention to the operation of
the system. If the liquid level and the pumping pressure are too low for a long
time, the system automatically stops the operation of the pumping motor, and
issued an alarm.
PID
control
l Constant
pressure water supply.
When opening
different numbers of solenoid valves, it is necessary to keep the water
pressure constant to avoid the increase in the water output and the decrease in
the water pressure, and the irrigation is not within the set irrigation range,
so the inverter must be changed through the PID adjustment calculation. The
operating frequency of the water pump can be changed to change the operating
speed of the pump motor to maintain the water supply pressure within a constant
range.
l Constant
pressure fertilizer supply.
When conveying
fertilizer, the pressure of the fertilizer pipeline must be greater than the
pressure of the water supply pipeline. Through the parameter setting adjustment
of PID, the pressure of the fertilizer pipeline is controlled within a constant
set value range to maintain the normal operation of fertilizer.
