PLC has been widely used in various industries such as steel, petroleum, chemical industry, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection, culture and entertainment at home and abroad. The usage is mainly divided into the following categories:
Switch logic control
It replaces the traditional relay circuit and realizes logic control and sequence control, which can be used not only for the control of a single device, but also for multi-machine group control and automated assembly lines. Such as injection molding machines, printing machines, bookbinding machines, combined machine tools, grinding machines, packaging production lines, electroplating lines, etc.
Industrial process control
In the industrial production process, there are some continuously changing quantities (ie analog quantities) such as temperature, pressure, flow rate, liquid level and speed. PLC adopts corresponding A/D and D/A conversion modules and various control Algorithm programs to process analog quantities to complete closed-loop control. PID adjustment is a commonly used adjustment method in general closed-loop control systems. Process control is widely used in metallurgy, chemical industry, heat treatment, boiler control and other occasions.
Motion Control
PLC can be used for circular motion or linear motion control. Generally, special motion control modules are used, such as single-axis or multi-axis position control modules that can drive stepper motors or servo motors, which are widely used in various machinery, machine tools, robots, elevators and other occasions.
Data processing
PLC has functions such as mathematical operations (including matrix operations, function operations, and logical operations), data transmission, data conversion, sorting, table lookup, and bit operations, which can complete data collection, analysis and processing. Data processing is generally used in some large control systems such as paper, metallurgy, and food industries.
Communication and networking
PLC communication includes communication between PLCs and communication between PLCs and other intelligent devices. With the development of the factory automation network, all PLCs now have communication interfaces, and the communication is very convenient.
