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The programmable logic controller
Its hardware structure is substantially the same to the microcomputer, the basic structure of:
First, the power
The power of the programmable logic controller plays a very important role in the whole system. If you do not have a good, reliable power system is not working properly, programmable logic controller manufacturer also attaches great importance to the design and manufacturing of power. The generally ac voltage fluctuations in the range of +10% (+15%), you can not take other measures the PLC directly connected to the AC line to
Second, the central processing unit (CPU)
The central processing unit (CPU) is the central control of the programmable logic controller. Functions entrusted to it in accordance with the programmable logic controller system procedures to receive and store type of user programs and data from the programmer; check the status of the power supply, memory, I / O, and watchdog timer, and the diagnosis of a syntax error in the user program. When the programmable logic controller is put into operation, first of all it is received in a scanning manner scene various status and data input device and stored in the I / O image area respectively, and then read one by one from the user program memory, the user program, after perform logical or arithmetic result of the provisions of the directive into the I / O image area or a data register command interpreter. After all of the user program execution, and the last of the data within the image area of each of the I / O output state or output registers are transferred to the corresponding output device, so that the loop runs, until it stops running.
In order to further improve the reliability of the programmable logic controller, and also used in recent years for large programmable logic controller the dual CPU constituting the redundant system, or using a three CPU voting system. Thus, even if a CPU fails, the entire system can still operate normally.
Third, the memory
A Memory to store system software referred to as a system program memory.
Application software storage memory called user program memory.
4, Input and output interface circuits
1. The live input interface circuit consists of an input interface circuit of the optical coupling circuit and a microcomputer, the role is a programmable logic controller and the input channel of the field control interfaces.
2. Scene output interface circuit by the output data registers, the gating circuit and interrupt request circuit integration, the role of the programmable logic controller through the field output interface circuit to output a corresponding control signal to the scene of the execution unit.
5, The functional module
Such as counting, positioning and other functional modules.
6, A communication module
Its hardware structure is substantially the same to the microcomputer, the basic structure of:
First, the power
The power of the programmable logic controller plays a very important role in the whole system. If you do not have a good, reliable power system is not working properly, programmable logic controller manufacturer also attaches great importance to the design and manufacturing of power. The generally ac voltage fluctuations in the range of +10% (+15%), you can not take other measures the PLC directly connected to the AC line to
Second, the central processing unit (CPU)
The central processing unit (CPU) is the central control of the programmable logic controller. Functions entrusted to it in accordance with the programmable logic controller system procedures to receive and store type of user programs and data from the programmer; check the status of the power supply, memory, I / O, and watchdog timer, and the diagnosis of a syntax error in the user program. When the programmable logic controller is put into operation, first of all it is received in a scanning manner scene various status and data input device and stored in the I / O image area respectively, and then read one by one from the user program memory, the user program, after perform logical or arithmetic result of the provisions of the directive into the I / O image area or a data register command interpreter. After all of the user program execution, and the last of the data within the image area of each of the I / O output state or output registers are transferred to the corresponding output device, so that the loop runs, until it stops running.
In order to further improve the reliability of the programmable logic controller, and also used in recent years for large programmable logic controller the dual CPU constituting the redundant system, or using a three CPU voting system. Thus, even if a CPU fails, the entire system can still operate normally.
Third, the memory
A Memory to store system software referred to as a system program memory.
Application software storage memory called user program memory.
4, Input and output interface circuits
1. The live input interface circuit consists of an input interface circuit of the optical coupling circuit and a microcomputer, the role is a programmable logic controller and the input channel of the field control interfaces.
2. Scene output interface circuit by the output data registers, the gating circuit and interrupt request circuit integration, the role of the programmable logic controller through the field output interface circuit to output a corresponding control signal to the scene of the execution unit.
5, The functional module
Such as counting, positioning and other functional modules.
6, A communication module
