Installation:
The installation mode of PLC system is divided into centralized, remote I/O and distributed with multiple PLC networking.
Centralized does not need to set up the drive remote I/O hardware, the system response is fast, and the cost is low; Remote I/O is suitable for large-scale systems, the system has a wide range of device distribution, remote I/O can be scattered and installed near the field device, the connection is short, but it is necessary to add a driver and remote I/O power supply; The distributed networking of multiple PLCs is suitable for the occasions when multiple devices are independently controlled and connected with each other, and small PLCs can be selected, but communication modules must be attached.
Feature Requirements
Generally, small (low-grade) PLC has functions such as logic operation, timing, and counting, which can be met for equipment that only needs to be controlled by switching quantity.
For the system with switching control and a small amount of analog control, an enhanced low-grade PLC with A/D and D/A conversion units, addition and subtraction arithmetic operations, and data transmission functions can be selected. For the control is more complex, it is required to realize PID operation, closed-loop control, communication networking and other functions, depending on the size and complexity of the control, the selection of mid-range or high-end PLC. However, medium and high-end PLCs are more expensive and are generally used in large-scale process control and distributed control systems.
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Megmeet inverter – the basic principle and application of high-voltage inverter
The basic principle of a high-voltage inverter
There are two categories of frequency conversion process of frequency converter: AC-AC form and AC-DC-AC form. Now it is mostly in the form of AC-DC-AC, and the following is a brief introduction to the working principle of this form.
Three-phase high-voltage electricity enters the high...
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Megmeet inverter – the energy-saving principle of low-voltage inverter
Inverter energy saving
The energy saving of the inverter is mainly manifested in the application of fans and pumps. In order to ensure the reliability of production, all kinds of production machinery are designed with power drive, and there is a certain amount of surplus. When the motor cannot operate at full load, in addition to meeting the power drive requirements, ...
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Megmeet PLC – the application of PLC
Open-loop control
Open-loop control of switching quantity is the most basic control function of PLC. The instruction system of PLC has powerful logic operation ability, and it is easy to realize various logic control methods such as timing, counting, and sequential (stepping). Most PLCs are used to replace traditional relay contactors...
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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 welding machine - introduction to the advantages and disadvantages of carbon dioxide gas shielded welding
Carbon dioxide gas shielded welding (referred to as CO2 welding) is the use of CO2 gas as the maintenance medium, during welding, CO2 gas is sprayed out through the nozzle of the welding gun, along the perimeter of the welding wire, forming a gas maintenance layer around the arc, mechanically isolating the welding arc and the molten pool from the air, and then avoiding ...
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Features of Megmeet CO2/MAG all-digital heavy-duty welder
1. The arc is stable in the field of full current, the spatter is small, and the same welding machine is not only suitable for small current base welding, but also suitable for high current and high deposition rate work
2. Arc concentration and strong penetration. With the same penetration depth, the heat input is reduced by more than 20% compared with other gas shielded welding machines, and the thermal deformation ...
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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 inverter - what are the main aspects of the development of inverter in the future?
1. Intelligent network
The intelligent inverter does not need to set a lot of parameters when it is used, and it has the function of fault self-diagnosis, which has high stability, high reliability and practicability. The Internet can be used to realize the linkage of multiple inverters, and even the inverter complex in the factory.
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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 PLC - What are the steps to complete PLC commissioning?
1. Check the circuit according to the drawing (without power transmission)
The drawings of the general PLC system include two parts: the drawings in the cabinet and the drawings outside the cabinet; The drawing in the cabinet refers to the wiring diagram inside the cabinet; The out-of-cabinet drawings are the wiring diagrams of all electrical cabinets.
This part needs to be checked for;
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Megmeet PLC - What are the features of the PLC program?
1. Correctness (low debugging cost)
First of all, the PLC program must be able to work correctly to meet the requirements of the actual control process. This is the essence of the PLC program, and if you don't do that, nothing else makes sense.
2. Reliability (low maintenance cost)
Not only to ...
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Megmeet inverter - maintenance precautions for high-voltage inverter
1. Carefully monitor and record the display parameters on the man-machine interface of the inverter, and reflect the abnormality immediately
2. Carefully monitor and record the ambient temperature of the frequency conversion room, and the ambient temperature should be between -5 °C and 40 °C. The temperature rise of the phase-shifting transformer should not exceed 130°C
3. Summer temperature ...
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Megmeet inverter - inverter braking mode and advantages and disadvantages introduction
What are the braking methods of the inverter? Generally speaking, braking refers to the technical measures taken during the operation of the motor due to fault protection or man-made active shutdown, and the commonly used inverter braking methods include energy consumption braking, feedback braking, DC braking and DC feedback braking. ...
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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 inverter - heating noise harmonic problems in inverter applications and countermeasures
First, some problems in the application of frequency converter
1.1
Harmonic problems
The devices that play a switching role in the main circuit of the inverter must generate harmonics in the process of turning on and off the circuit. The lower harmonics usually have a greater impact on the motor load, causing torque ripple; And the higher ...
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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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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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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 PLC - Introduction to the basic structure of PLC controller
1. 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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The principle of Megmeet plasma cutting and its characteristics
5) PLASMA
The principle of plasma cutting is: arc discharge between the base metal (including the nozzle in the cutting torch) and the electric in the cutting torch, and use the discharge heat energy to make the compressed gas produce a high-temperature and high-speed plasma arc to fuse the cutting method of the base metal. The small hole of the nozzle ...
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