PLC function classification and application scenariosAutomation has been applied to many industrial scenes. With the rapid development of computers in the 21st century, the global industrial level has also been greatly improved. The mature application of PLC is also an important symbol of industrial automation. The market is increasingly demanding industrial automation. Understanding the functional classification and application scenarios of PLCs will help beginners learn PLC and employment direction.
First, the switch logic control
Switching logic control is the basic of PLC, it is the first application scenario, and it is the most extensive in all application scenarios. It replaces the previous relay circuit control to achieve logic sequence control; it can be used for stand-alone equipment control, and can also be used for group machine control and automated factory assembly lines.
Switching logic control, applications such as: combined machine tools, grinding machines, packaging line production lines.
Second, analog control
In the process of industrial production, there are many quantities that will change continuously, such as temperature, pressure, flow, liquid level and speed. In order for the PLC to process these analog quantities, it is necessary to implement A/D and D/A conversion between analog and digital quantities. Nowadays, PLC manufacturers usually produce matching A/D and D/A conversion modules, which makes PLC easy to control analog quantity.
Third, motion control
The motion control module dedicated to the PLC body can drive a stepper motor or a servo motor to perform linear motion or circular motion. Nearly all major PLC manufacturers at home and abroad have motion control functions.
Motion control, applications such as: machinery, machine tools, elevators, etc.
Fourth, process control
As an industrial-grade control computer, PLC can program a variety of control algorithm programs to complete closed-loop control of temperature, pressure, flow and other analog quantities. PID regulation is used in closed-loop control systems. There are generally PID modules on large and medium-sized PLCs. Many small PLCs are now equipped with modules for this function.
Drying system PLC control chart, application occasions such as: metallurgy, chemical, heat treatment, boiler control, etc.
Fifth, data processing
The current PLC can complete data collection, analysis and processing, such as mathematical operations, data transfer, data conversion, sorting, table lookup and bit manipulation. These data can be compared with the reference values stored in the memory to perform certain control operations. Data processing is often used on large control systems. Applications such as flexible papermaking, textile, food industry and other large-scale control systems.
6. Communication and networking
With the development of automation networks in industrial plants, manufacturers of various PLCs attach great importance to the communication functions of PLCs, and have launched network systems with their own characteristics. The PLCs produced today are equipped with a communication interface, which makes communication between PLC and PLC, PLC and third-party equipment communication more convenient. The above points focus on quality. In terms of quantity, PLC is large or small, so its control range can be large or small. Small enough to control only one device, even a component, a site; large enough to control multiple devices, production lines and even entire plants.
In fact, PLC has been widely used in various fields of industrial production, such as steel, chemical, electric power, building materials, machinery manufacturing, automotive, textile, transportation, environmental protection and cultural entertainment, whether it is manufacturing or management inspection, You can see the shadow of the PLC, which is determined by the PLC's continuous improvement of its own characteristics.