Introduction to several mature fields of PLC
In recent years, programmable controllers (hereinafter referred to as PLC) have realized the leap of wiring logic to storage logic; its functions from weak to strong, achieving the progress of logic control to digital control; its application field from small to large, realized a single The body equipment is simply controlled to compete for various tasks such as motion control, process control, and distributed control. Today's PLC has greatly improved its ability to handle analog, digital computing, human-machine interface and network, and has become the mainstream control device in the field of industrial control, playing an increasingly important role in all walks of life.
At present, PLC has been widely used in various industries such as steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection and culture and entertainment. The usage is mainly divided into the following categories:
1. Switching logic control: replace the traditional relay circuit, realize logic control, sequence control, can be used for single device control, multi-machine group control and automatic assembly line. Such as injection molding machines, printing machines, bookbinding machines, combination machine tools, grinding machines, packaging production lines, electroplating lines, and so on.
2. Industrial process control: In the industrial production process, there are some continuous changes such as temperature, pressure, flow, liquid level and speed (ie analog quantity), PLC adopts corresponding A/D and D/A conversion modules and A variety of control algorithm programs to process the analog and complete the closed loop control. PID regulation is an adjustment method used in general closed-loop control systems. Process control has a wide range of applications in metallurgy, chemical, heat treatment, boiler control and other occasions.
3. Motion control: PLC can be used for the control of circular motion or linear motion. A dedicated motion control module, such as a single-axis or multi-axis position control module that can drive a stepper motor or a servo motor, is widely used in various machines, machine tools, robots, elevators, and the like.
4. Data processing: PLC has mathematical operations (including matrix operations, function operations, logic operations), data transfer, data conversion, sorting, table lookup, bit manipulation and other functions, can complete the data collection, analysis and processing. Data processing is commonly used in some large control systems such as paper, metallurgy, and food industries.
5. 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, the current PLC has a communication interface, and communication is very convenient.
At present, PLC has been widely used in various industries such as steel, petroleum, chemical, electric power, building materials, machinery manufacturing, automobile, textile, transportation, environmental protection and culture and entertainment. The usage is mainly divided into the following categories:
1. Switching logic control: replace the traditional relay circuit, realize logic control, sequence control, can be used for single device control, multi-machine group control and automatic assembly line. Such as injection molding machines, printing machines, bookbinding machines, combination machine tools, grinding machines, packaging production lines, electroplating lines, and so on.
2. Industrial process control: In the industrial production process, there are some continuous changes such as temperature, pressure, flow, liquid level and speed (ie analog quantity), PLC adopts corresponding A/D and D/A conversion modules and A variety of control algorithm programs to process the analog and complete the closed loop control. PID regulation is an adjustment method used in general closed-loop control systems. Process control has a wide range of applications in metallurgy, chemical, heat treatment, boiler control and other occasions.
3. Motion control: PLC can be used for the control of circular motion or linear motion. A dedicated motion control module, such as a single-axis or multi-axis position control module that can drive a stepper motor or a servo motor, is widely used in various machines, machine tools, robots, elevators, and the like.
4. Data processing: PLC has mathematical operations (including matrix operations, function operations, logic operations), data transfer, data conversion, sorting, table lookup, bit manipulation and other functions, can complete the data collection, analysis and processing. Data processing is commonly used in some large control systems such as paper, metallurgy, and food industries.
5. 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, the current PLC has a communication interface, and communication is very convenient.
