RAPIEnet based redundancy control system

Industrial Ethernet systems are attracting considerable attention as high-availability control systems. Many industrial customers are no longer satisfied with non-real-time Ethernet data transmission caused by low bandwidth, non-deterministic data transmission, and centralized network topology. To meet the requirements of these customers, the industry is focusing on high-availability industrial Ethernet technology. The `Real-time Automation Protocol for Industrial Ethernet´ (RAPIEnet) is a progressive industrial real-time protocol that can support line and ring topology Ethernet without external switches. In this paper, we introduce a new concept, known as a redundancy programmable logic controller (PLC), based on RAPIEnet. This PLC consists of a redundant CPU and redundant expansion drivers. The CPU can access all network devices through RAPIEnet, using the same access method as the local base devices, even if the device being accessed is located in the expansion base. The expansion base driver emulates CPU functionality to control devices in the expansion base by communicating with the CPU module. This relationship between the main controller and expansion controller provides a flexible and simple user control interface with high availability.