What is PLC
Programmable Logic Controller (PLC) is a digital computing electronic system designed for industrial environments.
It uses a programmable memory to store instructions for performing logical operations, sequential control, timing, counting and arithmetic operations, and controls various types of machinery or production processes through digital or analog input/output.
PLC and its related peripherals should be designed to be easy to form an integral part of the industrial control system and easy to expand its functions.
What modules does PLC consist of?
PLC usually consists of the following basic modules, the picture takes Siemens 1200 as an example:
1. Central Processing Unit (CPU): The CPU is the brain of the PLC, responsible for executing program logic, processing data and controlling the operation of the entire system. It contains a microprocessor, memory and some basic input/output interfaces.
2. Input/output module (I/O module): Input modules are used to receive external signals, such as sensor signals, while output modules are used to control external devices, such as motors, valves, etc. I/O modules can be expanded as needed to adapt to different application scenarios.
3. Power module: provides stable power supply for the PLC system to ensure stable operation of the system.
4. Communication module: used to realize data exchange between PLC and other devices or host computers, supporting multiple communication protocols such as Modbus, Profibus, etc.
5. Extension modules: Depending on specific application requirements, the PLC may also require some extension modules with special functions, such as analog input modules, special function modules, etc.
Function and purpose of each module
CPU: As the control center, it executes programs and processes data, and is the core of the entire PLC system.
I/O module: interacts directly with external devices to realize signal acquisition and output of control commands.
Power module: ensures that the PLC system can provide stable power supply under various working conditions.
Communication module: realizes remote transmission of data and interconnection between devices.
Extension module: provides additional functional support according to specific needs, increasing the flexibility and scope of application of PLC.
In short, PLC can flexibly adapt to different industrial automation needs through the combination of the above modules, from simple logic control to complex motion control and process control.
With the development of technology, PLC is also constantly evolving, becoming more intelligent and efficient.