Time Synchronization Transfer Nodes for Fast GM Switchover
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Solution Overview
Problem
Conventional time synchronization systems in industrial Ethernet networks face issues with reliability and synchronization accuracy due to independent transmission cycles of Announce and Sync/Follow_up messages, leading to delayed detection of time source deterioration and reconfiguration delays when switching GMs, and lack of interconnectivity and scalability in existing solutions.
Innovation Solution
A transfer apparatus and time selection system that integrates time source information and deterioration notification, ensuring faster delivery of new time information while maintaining interconnectivity and scalability by monitoring Announce message reception states and synchronizing time through synchronized Sync/Follow_up messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If independent transmission cycles are used for Announce and Sync/Follow_up messages, then device complexity is reduced and ease of operation is improved, but reliability deteriorates due to delayed detection of time source deterioration
Solution Approach 1:
The patent combines the transmission cycles of Announce messages and Sync/Follow_up messages by making the Sync/Follow_up message transmission cycle a divisor of the Announce message transmission cycle. This synchronization ensures that when Announce messages are transmitted, Sync/Follow_up messages are also transmitted, enabling coordinated detection and transmission of time source status without requiring complex independent cycle management.
2Reliability
If Announce message transmission cycle is shortened to improve detection speed, then reliability improves, but loss of energy increases due to more frequent transmissions
Solution Approach 1:
The patent implements periodic action by establishing a fixed relationship between Announce and Sync/Follow_up message cycles. The Sync/Follow_up message cycle is set as a divisor of the Announce message cycle, creating a hierarchical periodic structure that ensures timely detection while avoiding excessive transmission frequency. This periodic coordination allows the system to detect time source deterioration reliably without continuous high-frequency transmissions that would waste energy.
3Reliability
If multiple time sources are arranged in network for high reliability, then reliability improves, but device complexity increases due to BMCA algorithm coordination
Solution Approach 1:
The patent applies feedback by using Sync/Follow_up messages to provide real-time information about time source status and propagation delay to all network devices. This feedback mechanism works in conjunction with the BMCA algorithm to enable dynamic clock tree configuration and GM reselection. When time source deterioration is detected through the synchronized message transmission, the feedback information triggers automatic reconfiguration, managing multiple time sources without requiring complex manual coordination.
Data Source
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AI summary
A transfer apparatus (10) includes a Pdelay message reception process (101), a Sync/Follow up message reception process (102), an Announce message reception process (103), a Sync reception/transmission guard management process (104), a delay measurement arithmetic process (105), a time synchronization arithmetic process (106), a time selection arithmetic process (107), and a frame transmission process (108). The transfer apparatus (10) monitors a reception state of an Announce message (61) that notifies of time source information for each port, and in a case where, based on monitoring, a state of a time source worsened as in when reliability of time is reduced and the like, a Sync/Follow_up message (51) for time synchronization is made so as not to be transferred. By the above, the transfer apparatus (10) makes a time out of the Sync/Follow_up message (51) occur and worsening of the time source is notified to a different apparatus at high speed.