How does the VB100 terminal in Siemens PLC represent byte data?

How does the byte data in plc represent peripheral terminals such as VB100 in Siemens PLC

1. There is a concept in PLC called data storage area. The data storage area is divided into I input, Q output, M internal memory bit, SM special memory bit, V variable memory, etc. Each area has The data type can be used to represent its length. For example, the VB100 you mentioned means that the V variable is one B (byte) in size, the byte address is 100, and one byte is 8 bits. The byte VB100 includes VB100.0, VB100.1, VB100.2, VB100.3, VB100.4, VB100.5, VB100.6, VB100.7 total 8 bits. Another example: QW0, Q represents the output storage area, W represents the length of a word, the address is 0, a word includes two bytes, a total of 16 bits, then QW0 includes two bytes QB0 and QB1, QB0 is The upper 8 bits, QB1 is the lower 8 bits.

Peripheral terminals usually refer to the interface of external devices connected to computers or other devices, used to transmit data or control signals. PLC (Programmable Logic Controller) also has input and output terminals for receiving and sending signals. Among them, I represents the identifier of the input area, and Q represents the identifier of the output area. For example, the input terminals are marked I0.0, I0.1, I0.2, I0.3, etc., indicating input signals of different bit sizes. In the program, you can use these bits to control the program, or you can use IB0 (8 bits in total 0.0-0.7) to control the program, depending on the needs of the program. For example: LD I0.0 means loading the I0.0 input signal.

2. = QB0

This means that when I0.0 input has a signal, the 8 output points Q0.0 to Q0.7 all have signal output

It’s so long-winded, can you understand it?

What does I0 1 M0 2 mean in plc

I0.0 I0.1 M0.1 Q0.1 M0.0 Q0.2 are all register addresses in Siemens PLC.

1, I0.0 and I0.1 refer to the input module, that is, the DI module numbered 0, with its two contacts 0 and 1;

2. M0.0 and M0.1 are internal M contactors, with address bit 0, bit 0 and bit 1;

3, Q0.1 and Q0.2 refer to the output module, that is, the DO module numbered 0, with its two contacts 1 and 2.

Extended information:

PLC is developed by imitating the original relay control principle. In the 1970s, programmable controllers only had switching logic controls. The first application is in the automotive manufacturing industry. It stores instructions to perform logical operations, sequence control, timing, counting, and operations, and controls various types of machinery or production processes through digital input and output operations.

The control program written by the user expresses the technological requirements of the production process and is stored in the user program memory of the programmable controller in advance. During the operation, the program is executed one by one according to the stored program content to complete the operations required by the process.

The central processing unit of the programmable controller has a program counter that indicates the storage address of the program steps. During program operation, the counter is automatically incremented by 1 at each step of execution.

Reference source: Sogou Encyclopedia-Programmable Logic Controller

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