The working principle of PLC is: when the PLC controller is put into operation, its working process is generally divided into three stages, namely, input sampling, user program execution and output refresh. The completion of the above three phases is called a scanning cycle.
1. Input sampling phase
In the input sampling phase, the PLC controller reads all input states and data in turn in scanning mode, and stores them in the corresponding unit in the Imax O image area. After the input sampling is finished, it is transferred to the user program execution and output refresh phase.
2. User program execution phase
During the execution phase of the user program, the PLC controller always scans the user program (ladder diagram) in order from top to bottom.
3. Output refresh phase
When the scanning user program is finished, the PLC controller enters the output refresh phase. During this period, CPU refreshes all output latch circuits according to the corresponding state and data in the Ihammer O image area, and then drives the corresponding peripherals through the output circuit.
Extended data:
The basic structure of PLC is:
1. Central processing unit
Central processing unit (CPU) is the control center of PLC controller. It receives and stores the user program and data typed from the programmer according to the function given by the PLC controller system program, checks the status of the power supply, memory, Ibank O and alarm timer, and can diagnose syntax errors in the user program.
2. Memory
The memory where the system software is stored is called the system program memory. The memory where the application software is stored is called the user program memory.
3. Power supply
The power supply of PLC controller plays a very important role in the whole system. Without a good and reliable power supply system, it will not work properly, so the manufacturers of PLC attach great importance to the design and manufacture of power supply.
4. Program input device
Responsible for providing the functions used by the operator to input, modify and monitor the program.
5. Input / output circuit
Responsible for receiving external input component signals and external output component signals.
Source: Baidu Encyclopedia-PLC system
How does the automatic feeder work? what is the principle?
Automatic feeder
The electric control system of the system is mainly composed of AC contactor, sensor, switch, indicator light and so on.
Working principle: driven by the motor, the spiral spring winch in the conveying pipe does not continue to rotate to promote the feed to be transported to each plate. The system will judge whether there is material in the front material box, if there is material, the control motor rotates; if the material box is empty, the control motor rotates; at the same time, the detection tray installed at the end of the material line is also testing whether the material line has been filled up. If it is full, the control motor stops rotating, if it is not filled, the control motor continues to rotate, and the whole feeding process achieves automatic control. After using the automatic feeding system, the breeder only needs to pour the material into the front box, and then the feeding is completed automatically by the system, and the feeding process is quite easy.
Features:
1. The feeding is uniform and easy to operate.
two。 The feed size can be adjusted.
3. Equipped with three-dimensional feed lifting and horizontal conveying and feeding system.
4. The feeding mechanization can be realized completely.
5. The area is small, and the four-row feeder has only two tracks.
6 for the non-standard layout of small and medium-sized chicken farm facilities, its structure is unique, novel and practical, time-saving and labor-saving, less loss, low noise, convenient operation, convenient maintenance, and can feed three to four floors at the same time.
What is a weightlessness feeder?
The weight data and time change are collected continuously by the electronic weighing sensor, and the weight change per unit time is calculated by PLC or computer system, that is, the rate of feeding. The accuracy of the weight loss feeder depends on the measurement accuracy and sampling frequency of the gravity sensor.
This is the end of the introduction of the PLC control principle of the weightlessness feeder. Thank you for taking the time to read the contents of this site. Don’t forget to look for more information about the weightlessness feeder schematic diagram and the PLC control principle of the weightlessness feeder.
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