EtherCAT Clock Synchronization With Cable Redundancy Recovery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In EtherCAT networks, disconnections cause a failure in both cable redundancy and distributed clock synchronization mechanisms, leading to synchronization issues among slave devices.
Innovation Solution
The proposed method and master device architecture support both cable redundancy and distributed clock synchronization by using a junction device to manage connections and perform distributed clock synchronization procedures, even in the presence of disconnections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed clock synchronization is performed in redundant mode, then synchronization is maintained during disconnections, but system time delay calculation becomes complex
Solution Approach 1:
The system pre-calculates and stores multiple system time delay values corresponding to different network topologies (redundant mode and non-redundant mode) before disconnections occur. When a disconnection is detected, the system directly applies the pre-stored appropriate time delay value without performing complex real-time calculations, thus maintaining synchronization while simplifying the operational complexity
2Measurement precision
If re-synchronization is performed after reconnection, then clock accuracy is restored, but system downtime increases
Solution Approach 1:
The system maintains continuous clock synchronization capability during disconnections by operating in redundant mode, allowing slave devices to self-maintain synchronization without external intervention. Upon reconnection, the system automatically switches back to non-redundant mode without requiring re-synchronization procedures, thereby eliminating additional downtime while preserving clock accuracy
Data Source
Figure 1~2
Figure 3A
Figure 3B
AI summary
In the initial phase, the master device (200) is configured to disable the connection between the junction device (SA) and the last slave device (SN) before performing the EtherCAT distributed clock synchronization procedure. After completion, the connection between the junction device (SA) and the last slave device (SN) is enabled. When a disconnection occurs in a closed loop topology, the junction device (SA) can serve to provide a redundant path for forwarding datagrams, thereby achieving cable redundancy. After the disconnection is fixed, the system time delay of each slave device calculated during the initial phase can still be applied without needing to perform again the distributed clock synchronization procedure.