The EPA System Structure and Communication Specification for Industrial Measurement and Control Systems (hereinafter referred to as EPA) is a real-time communication specification based on Industrial Ethernet, which effectively solves the deterministic communication problem of Ethernet communication and can be applied to many The industrial field constitutes various industrial measurement and control systems. The specification will be included in the established real-time Ethernet international standard IEC61784-2, becoming the first fieldbus standard with independent intellectual property rights in China; developing and implementing the EPA communication protocol is the basis and premise of applying the EPA system. μC/OS-II is a real-time multi-tasking embedded operating system with preemptive mechanism. It has the characteristics of open source, portable, curable and tailorable, and has been widely used. Compared with μClinux, which is also open source code, it has the characteristics of small kernel and high real-time performance, which is more suitable for control applications. As the implementation platform of EPA communication protocol, μC/OS-II can greatly improve the utilization of system resources, and obtain better real-time response performance by prioritization. Multiple communication methods between tasks help to realize the status of each entity protocol. machine. The EPA system uses the first, second, third, fourth and seventh layers of the ISO/OSI Open Systems Interconnection Model (ISO 7498) and adds user layers. In addition to the common Ethernet protocol components in the system, some layers add some entities to meet the needs of EPA communication: The added user layer contains EPA function block application processes and non-real time application processes. The application layer adds an EPA protocol consisting of an EPA system management entity, an EPA application access entity, and an EPA socket mapping entity. The three entities implement EPA device management, application communication services, and application layer and UDP/IP software entities. Mapping interface and packet priority transmission management, packet encapsulation, response information return, and link status monitoring. An EPA communication scheduling management entity is added between the MAC layer and the IP layer to perform scheduling management on the packets sent by the EPA device to the network. The scheduling strategy adopts a time-sharing mechanism to divide the message into periodic messages and aperiodic messages, and send them in the corresponding time period according to the pre-configured scheduling scheme to avoid collision. Each device network time is maintained by the time synchronization component for consistency. The EPA Management Information Base provides information required for operations at various layer protocol entities, including device description objects, link objects, and so on. According to the EPA communication protocol, each EPA device consists of at least one functional block instance, EPA application access entity, EPA system management entity, EPA socket mapping entity, EPA link object, communication scheduling management entity, and UDP/IP protocol. composition. Each entity and object call each other and cooperate to complete the communication process between devices as shown in Figure 1: Fiber Optic Patch Panel,Fiber Patch Panel,Fiber Distribution Panel,Optical Patch Panel Cixi Dani Plastic Products Co.,Ltd , https://www.dani-fiber-optic.com