(1) Central Processing Unit (CPU)
The central processing unit (CPU) is the control center of the PLC. It accepts and stores user programs and data typed from the programmer according to the functions assigned by the PLC system program, checks the status of the power supply, memory, I/O and alert timer, and can check the syntax errors of the user program. When the PLC is put into operation, it first receives the status and data of each input device on the site in the form of scanning, and stores them in the I/O image area respectively, and then reads the user program from the user program memory one by one, and executes tasks such as logic or arithmetic operations according to the provisions of the instructions after command interpretation. Logical or arithmetic operations are fed into the I/O image or data registers. After all user programs have been executed, the output status of each output in the I/O image area or the data in the output registers is transferred to the corresponding output device, and so on until the operation is stopped.
(2) Memory
As with a microcomputer, there must be software in addition to the hardware. in order to form a complete PLC. The software of PLC is divided into two parts: system software and application software. The memory that holds the system software is called the system program memory.
Allocation of PLC storage space: Although the maximum addressable storage space of the CPU of large, medium and small PLC varies, according to the working principle of PLC, its storage space generally includes the following three areas: system program storage area, system RAM storage area (including I/O image area and system software equipment, etc.) and user program storage area.
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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 welding machine - Classification and difference of laser spot welding machine
Laser spot welding machine, also known as resistance welding machine, is usually divided into three categories according to the nature of the welding power source: 1. AC spot welding machine; 2. Energy storage spot welding machine; 3. DC spot welding machine.
1. AC spot welding machine
Precision AC spot welding machine generally refers to the spot welding machine with a power of less than 16KVA.
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The principle and characteristics of Megmeet tungsten argon arc welding and resistance welding
3) Tungsten argon arc welding (TIG)
Non-melting electrode gas arc welding, TIG welding, English is Tungsten Inert Gas (abbreviated TIG), also known as Gas Tungsten Arc Welding (abbreviated GTAW)
The principle is: TIG welding is in argon and other inert gases.
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The cause and treatment method of the fault code Eroc1 of Megmeet inverter
1. Overcurrent fault of inverter
Fault Code: OCF.
(1) Fault name: inverter overcurrent fault
(2) The cause of the failure: the motor nameplate data input is incorrect: the load dragged by the motor is too heavy: the machinery is stuck; Motor stalled.
(3) ...
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Megmeet drives – a common fault in low-voltage drives
External electromagnetic interference can easily cause malfunctions
If there are interference sources around the inverter, they will invade the inside of the inverter through radiation or power lines, causing the control loop to malfunction, causing abnormal operation or shutdown, and even damage to the inverter in severe cases. Noise suppression on the outside ...
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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 new energy vehicle PEU intelligent manufacturing production line was put into use
Zhuzhou Lihui Technology Co., Ltd., a subsidiary of Megmit, has put into use a new production line of PEU intelligent production of new energy cars, leading the wave of intelligent production of PEU in the key "three electric" components of domestic new energy cars.
Zhuzhou Lihui Technology Co., Ltd. production workshop, a new ...
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Megmeet welding machine – the main feature of the laser welding machine
(1) The energy density is highly concentrated, the heating and cooling speed is extremely fast during welding, the heat affected zone is small, and the welding stress and deformation are very small;
(2) Non-touch processing, no external force on the weldment, suitable for welding parts that are difficult to touch;
(3) The laser can be transmitted through the optical incoming ...
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Megmeet inverter - the basic method and steps of inverter commissioning
1. No-load energizing test of inverter
1. Ground the grounding terminal of the inverter.
2. Connect the power input terminal of the inverter to the power supply through the leakage maintenance switch.
3. Check whether the factory display of the inverter window is normal, if it is incorrect, it should be reset, otherwise it should be ...
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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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Megmeet PLC - What are the five stages of the PLC work process?
1. Common processing: reset the monitoring timer, perform hardware checks, user memory checks, etc.
2. Program execution: The CPU interprets and executes each instruction in the order of first left and then right, first up and then down, and reads out each relay according to the input image register and the component image register.
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Megmeet PLC - the difference between PLC and frequency converter
1. The role is different
A PLC (Programmable Logic Controller) is an electronic system designed for digital operations in an industrial environment.
The inverter is the application of frequency conversion technology and microelectronics technology to control the AC motor by changing the frequency of the motor working power supply.
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Megmeet inverter – the difference between voltage type inverter and current type inverter
1. The load of the buffer inverter without functional quantity is an asynchronous motor, which is an inductive load, and in addition to transmitting active power between the intermediate DC link and the motor, there is also the exchange of reactive power. Since the power electronic switching devices cannot be stored for energy, the non-functional energy can only rely on the energy storage elements (filters).
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Megmeet PLC common faults
1. External equipment failure. Such faults come from external devices such as various sensors, switches, actuators, and loads. The failure of this part of the equipment will directly affect the control function of the system. This type of failure is usually caused by the quality and longevity of the equipment itself.
2. System failure ...
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Megmeet Welders – What are the commonly used types of welders?
1. The main welding machines used in industrial and mining enterprises are: AC arc welding machine, DC electric welding machine, argon arc welding machine, carbon dioxide maintenance welding machine, butt welding machine, spot welding machine, submerged arc welding machine, high-frequency welding machine, bright butt welding machine, pressure welding machine, butt welding machine and laser welding machine.
Communication welders and DC welders should ...
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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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The unified setting of the Megmeet welding machine and the parameter setting of the system
1. Unified setting of Megmeet welding machine
The so-called unification of welding means that the welding machine automatically matches the welding voltage according to the currently set welding current and the unification voltage correction value.
The unification setting of Megmeet welder should first turn on the function on the welder side, ...
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Megmeet PLC - What is the difference between PLC and servo control system
1. The meaning of the representation is different:
PLC is the abbreviation of planar optical waveguide (technology), the so-called planar optical waveguide, means that the optical waveguide is located in a plane.
A servo control system is a feedback control system used to accurately follow or reproduce a certain process.
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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 PLC - the characteristics of the working process of PLC
1. The PLC adopts the mode of centralized sampling and centralized output, which can reduce the influence of external interference.
2. The working process of PLC is the process of cyclic scanning. The duration of the cyclic scan depends on the speed of execution of the instructions and the length of the user's program.
3. Output to input ...
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