"基于PLC的可程序设计控制自动门系统设计与优化"

The automatic door control system based on PLC (Programmable Logic Controller) and frequency converter control has been widely used in large companies, research institutes, and government agencies with high confidentiality. In order to enhance the reliability of automatic door operation, this design proposes a control system for automatic doors that incorporates a PLC and a frequency converter. The design adopts two induction sensors (inside and outside the door), as well as several switches and sensors as input devices for the system. The frequency converter is used to adjust the speed of the door, and the working principle and hardware composition of the control system are analyzed. This design also analyzes the working process of the control circuits for human body sensing detection, automatic door position detection, and obstacle detection during door operation. Detailed explanations are given regarding the selection of PLC and frequency converter, determination of I/O points, and the process of automatic door action. Taking into account the characteristics of PLC operation, the workflow of the control system is optimally designed. Based on this, the design provides program flowcharts, sequential function charts, external terminal connection diagrams, and PLC ladder diagrams for the software design of the control system. This design introduces the application of a programmable logic controller to replace traditional relay and contactor control systems, realizing the process of automatic door control. Keywords: automatic door; programmable logic controller; ladder diagram; frequency control