Development trend of PLC

At present, PLC has been widely used in steel, petroleum, chemical industry, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection, culture and entertainment industries at home and abroad, and its uses are mainly divided into the following categories:

1. Switch logic control replaces the traditional relay circuit to realize logic control and sequence control, which can be used for single machine control, multi-machine group control and automatic production line. Such as injection molding machine, printing machine, stapler, modular machine tool, grinder, packaging production line, electroplating production line, etc.

2. Industrial Process Control In the industrial production process, there are some continuously changing quantities (namely analog quantities), such as temperature, pressure, flow, liquid level and speed. PLC adopts corresponding A/D, D/A conversion modules and various control algorithm programs to process analog signals and complete closed-loop control. PID regulation is a widely used regulation method in general closed-loop control system. Process control is widely used in metallurgy, chemical industry, heat treatment, boiler control and other occasions.

3. Motion control PLC can be used to control circular motion or linear motion. Generally, special motion control modules are used, such as single-axis or multi-axis position control modules that can drive stepping motors or servo motors, which are widely used in various machinery, machine tools, robots, elevators and other occasions.

4. Data processing PLC has the functions of mathematical operation (including matrix operation, function operation and logic operation), data transmission, data conversion, sorting, table lookup and bit operation, and can complete data acquisition, analysis and processing. Data processing is generally used in some large-scale control systems, such as papermaking, metallurgy, food industry and so on.

5. Communications and networks

PLC communication includes communication between PLCs and communication between PLCs and other intelligent devices. With the development of factory automation network, now PLC has communication interface, and communication is very convenient.

Thus, the development trend of plc