Reference Timer Selection for Network Path-Based Clock Synchronization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In factory automation (FA) systems, high clock time synchronization accuracy is required among control targets, but communication delays due to increasing network path lengths in larger systems lead to variations in synchronization accuracy, which existing methods, such as those described in Patent Literature 1, do not adequately address by considering transmission path lengths.
Innovation Solution
A control system that includes a timer decision mechanism to select a reference timer based on path indicators indicating the length of network paths for each transfer apparatus, ensuring a constant communication delay and accuracy in clock time synchronization, involving path indicator acquisition, accuracy indicator calculation, and candidate selection to determine the most suitable reference timer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the scale of FA systems increases, then the system can handle more control targets, but communication delays increase due to longer network paths
Solution Approach 1:
The patent applies local quality by selecting different reference timers for different control targets based on their specific network path characteristics. Instead of using a single reference timer for the entire system, each control target uses a reference timer that is optimally positioned relative to it, considering the local network topology and path length. This resolves the contradiction by allowing the system to scale while maintaining acceptable communication delays for each individual control target.
2Device complexity
If a single reference timer is used for all control targets, then the system structure is simplified, but clock time synchronization accuracy varies among control targets
Solution Approach 1:
The patent implements local quality by allowing different control targets to use different reference timers based on their network distance and communication characteristics. Control targets with shorter network paths can use reference timers that provide higher synchronization accuracy, while the overall system structure remains manageable through automated selection mechanisms.
Solution Approach 2:
The patent applies dynamics by enabling the reference timer assignment to be flexible and adaptable rather than fixed. The system can dynamically select appropriate reference timers for different control targets based on network conditions, path lengths, and synchronization requirements, allowing the system to optimize performance without increasing structural complexity.
3Device complexity
If reference timer selection ignores path length, then the selection process is simpler, but clock time synchronization accuracy deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing network path information (such as path lengths and communication delays) before the reference timer selection process. This preliminary preparation allows the selection algorithm to quickly determine the optimal reference timer for each control target without performing complex real-time calculations, thus maintaining simplicity in the selection process while achieving high synchronization accuracy.
Data Source
AI summary
The present invention decides a reference timer for synchronizing time in consideration of an indicator which indicates a length of a transmission path. A timer decision means for deciding a reference timer out of timers having a plurality of transfer apparatuses acquires, for each of the plurality of transfer apparatuses, a path indicator which indicates a length of a path on a network through which data passes from the transfer apparatus to an end apparatus, and decides a reference timer out of timers of one or more transfer apparatuses having the path indicator which indicates that a path to the end apparatus has a predetermined length out of the plurality of transfer apparatuses.