1. Input processing
Input processing is also called input sampling. In this phase, the through-end state of all input terminals is read sequentially, and the read information is stored in the corresponding image register in memory. Here the input image register is flushed. Then the program execution phase begins. When the program is executed, the input image register is isolated from the outside world, and even if the input signal changes, the contents of the image register do not change, and the information can only be read into the input processing phase of the next scan cycle.
2. Program Execution
According to the principle of PLC ladder program scanning, scan sentence by sentence and execute the program according to the step sequence of first left, then right, first up and then down. When a program redirects a program, the redirection address of the program is determined based on whether the redirection conditions are met. When the input and output states are involved from the user program, the PLC reads out the corresponding input terminal state adopted in the previous stage from the input image register, reads the corresponding image register from the output image register, performs logical operations according to the user program, and stores it in the relevant device register. For each device, the contents of the device image registers will change as the program is executed.
3. Output processing
After the program is executed, the output image register, that is, the state of the Y register in the device image register, is transferred to the output latch in the output processing stage, and the power amplification circuit is driven through the isolation circuit, so that the output terminal outputs the control signal to the outside world and drives the external load.
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Megmeet drive common fault repair methods
When the oscilloscope looks at the current monitoring output of the driver, it is all noisy and cannot be read
Cause: The current monitoring output is not blocked from the AC power supply (transformer).
Solution: You can use a DC voltmeter to detect and investigate.
Servo motor high-speed rotation ...
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Hollysys edge intelligent controller and edge intelligent all-in-one machine launched new products
Transportation power, urban rail responsibility. With the vigorous development of emerging technologies such as 5G, cloud computing, big data, and artificial intelligence, more innovative technologies are accelerating the empowerment of urban rail transit, and smart urban rail is ushering in a "golden age" of development. As a deep cultivator in the field of smart urban rail, Hollysys adheres to technological innovation.
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Megmeet inverter - introduction to the classification of inverters
1. Classified according to the input voltage level
According to the input voltage level, the inverter can be divided into low-voltage inverter and high-voltage inverter, and the low-voltage inverter is common in China with single-phase 220 V inverter, three-phase 220 V inverter, and i-phase 380 V inverter. High-voltage inverters are commonly used in 6 kV, 10 kV transformers.
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Various welding methods for Megmeet welding machines
1) Hand arc welding (STICK)
Shielded Arc Welding (abbreviated SMAW) in English,
The principle is: the arc occurs between the coating electrode and the base metal, and the welding method of arc thermal ablation electrode and base metal is used. The outer layer of the electrode is covered with solder, which is dissipated in case of heat.
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Megmeet Inverter - Precautions for the Use of Inverter (11-21)
11. For the occasion when the inverter drives the ordinary motor for constant torque operation, long-term low-speed operation should be avoided as much as possible, otherwise the heat dissipation effect of the motor will become worse and the heating will be serious. If long-term operation at low speed constant torque is required, a variable frequency motor must be selected.
12. For the promotion of negative ...
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Megmeet welding machine - an introduction to the advantages and disadvantages of resistance welding
Advantages of resistance welding:
1。 When a nugget is formed, it is always surrounded by a ring of plastic, the molten metal is isolated from the air, and the metallurgical process is simple
2。 The heating time is short, the heat is concentrated, the heat affected zone is small, and the deformation and stress are small. In general, there is no need to arrange calibration and heat after welding.
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New Arrivals! Hollysys' two blockbuster products were unveiled at the Zhongguancun Forum Technology Trading Conference
On September 24, the 2021 Zhongguancun Forum, co-sponsored by the Ministry of Science and Technology of China, the Chinese Academy of Sciences, the China Association for Science and Technology, and the Beijing Municipal People's Government, officially opened in Beijing. As one of the main agendas of the forum, the Zhongguancun International Technology Exchange Conference closely follows the "smart· healthy· carbon neutrality...
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Megmeet PLC - the hardware composition of PLC control
1. Power components
The power supply assembly is used to provide the power required for the operation of the PLC, and the external power supply can be converted into a power supply for the PLC internal and applicable to the case.
2. Microprocessor CPU and memory components
Microprocessor CPU is the core device of PLC, and CPU is different from each manufacturer.
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Megmeet inverter – three ways to connect the PLC to the inverter
(1) Use the analog output module of PLC to control the analog output module of the inverter The analog output module of the PLC outputs 0-5V voltage signal or 4-20mA current signal, which is used as the analog input signal of the inverter to control the output frequency of the inverter. This control method is simple to wiring, but it needs to be selected and changed.
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Megmeet PLC – the three output types of PLC
The first is relay output, the relay output response speed is slow, the output current is large, generally can reach 2A, but the electric shock life is short, the output frequency is low, the maximum is 1HZ;
The second is transistor output, the transistor output response speed is fast, the output current is small, and the contact life is relatively small.
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Megmeet inverter – failure analysis of air compressor inverter
1. The voltage is unstable
In the process of using the inverter air compressor, sometimes the voltage is unstable. If the voltage is unstable, a load may occur, causing the compressor to not start properly. Solution: The regulator can be adjusted in time.
2. The main ...
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Megmeet drives – the replacement steps for high-voltage drive power units
1) Shut down, so that the inverter out of the operating state;
2) Cut off the high-voltage power supply and push out the high-voltage cabinet trolley (when there is a bypass cabinet. The inverter can be isolated by the disconnecting switch of the bypass cabinet), the local or remote high-voltage disconnect switch can be locked, and the high-voltage cabinet grounding switch can be grounded;
3) Hit ...
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Megmeet inverter - 5 precautions for the use of inverter
1. The circuit board inside the inverter belongs to precision electronic components, which needs to be moisture-proof and dust-proof, and the temperature and humidity are not too high, and cannot be installed on the bare wall, so the inverter should be installed in the middle of the control cabinet; The inverter should be installed vertically, and the installation should be avoided directly above and below ...
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Analysis of the fault code of Megmeet welder
1. E1: indicates sensor failure. In this case, it is necessary to check whether the sensors of Megmeet are damaged or whether the wiring is loose.
2. E2: Indicates overweight load. At this point, it is necessary to check whether the load of Megmeet exceeds the set maximum load.
3. E3: Indicates battery ...
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Megmeet PLC – three connection methods for PLC and frequency converter
1. Use the analog output module of the PLC to control the inverterThe analog output module of the PLC outputs a 0-5V voltage signal or a 4-20mA current signal, which is used as the analog input signal of the inverter to control the output frequency of the inverter. This control method is simple to wiring, but requires the option to ...
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Megmeet PLC - the basic composition of PLC
a. Power supply
The power supply of the PLC plays a very important role in the whole system. It can't work properly without a good and reliable power supply system, so PLC manufacturers also attach great importance to the design and manufacture of power supplies. General AC voltage fluctuations are +10% (+15%) ...
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Megmeet PLC maintenance and processing methods
1. CPU abnormality: When the CPU is abnormally alarmed, check the device connected to the internal line of the CPU unit. The specific method is to replace the units that may cause failures in turn, find out the faulty units, and deal with them accordingly.
2. Memory abnormality: When the memory is abnormal alarm, if it is a program ...
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Megmeet Inverter - Summary of Common Faults of High Voltage Inverter (1-10)
1。 How do you distinguish between heavy and light failures?
When the fault is light, the system sends out an alarm signal, and the fault indicator flashes. When a major fault occurs, the system issues a fault indication, and the fault indicator is always on. At the same time, a command is issued to break the high voltage and close the prohibition, and the fault information and high voltage are instructed.
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Megmeet welding machine - the working principle of the spot welding machine and its advantages and disadvantages are introduced
Safety operation procedures for spot welding machines:
1. Before operation, the oil stain of the upper and lower electrodes should be removed. After power-on, the body shell should be free of leakage.
2. Before starting, the steering switch of the control line and the small switch of welding current should be connected, the number of poles should be adjusted, and then the water source and gas source should be connected.
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Megmeet inverter - heat dissipation design considerations for high-power high-voltage inverters
(1) Select components and materials with good heat resistance and thermal stability to increase their allowable working temperature;
(2) Reduce the heat generated inside the equipment (device). To this end, micropower devices, such as low-loss IGBTs, should be used more often, and the number of heat-generating components should be minimized in the circuit design.
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