Local Clock Correction With Reduced Time Synchronization Traffic
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing control systems face challenges in maintaining synchronization between a host clock and local clocks in a networked control system, leading to increased communication load and inefficiencies due to frequent time synchronization processes.
Innovation Solution
A control system that reduces the frequency of time synchronization processes by periodically determining communication timings for data exchange with a time master, limiting the frequency of correction processes, and employing a limiting unit to block response signals, thereby reducing communication load while maintaining synchronization accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If frequent time synchronization processes are performed to maintain synchronization accuracy between host clock and local clocks, then synchronization accuracy is improved, but communication load increases
Solution Approach 1:
The patent implements periodic time synchronization where the local controller performs data exchange with the time master at reduced intervals (e.g., every 10th or 100th synchronization signal) rather than continuously. This periodic action maintains adequate synchronization accuracy while significantly reducing the quantity of communication transactions, thereby resolving the contradiction between synchronization precision and communication load.
2Quantity of substance
If the frequency of time synchronization processes is reduced to decrease communication load, then communication load is reduced, but synchronization accuracy deteriorates
Solution Approach 1:
The local controller performs preliminary acquisition of the offset value during initial synchronization or at extended intervals, then applies this offset value for multiple subsequent clock corrections without requiring immediate re-synchronization. This preliminary action allows the system to maintain synchronization accuracy over extended periods between communication events, reducing communication load while preserving timing precision.
Solution Approach 2:
The system acquires the offset value from the time master and creates a local copy that is reused for multiple clock correction cycles. Instead of continuously querying the time master, the local controller utilizes this copied offset information to maintain accurate local clock timing, thereby reducing communication frequency while preserving synchronization accuracy.
3Reliability
If continuous data exchange with time master is performed to maintain synchronization, then synchronization reliability is improved, but system complexity increases
Solution Approach 1:
The system implements periodic data exchange at predetermined intervals rather than continuous communication. The local controller determines communication timing based on received synchronization signal intervals and performs data exchange only at these periodic moments. This approach maintains synchronization reliability by ensuring regular updates while reducing system complexity by eliminating the need for continuous communication monitoring and processing.
Data Source
AI summary
A control system includes: a time master configured to periodically transmit synchronization signals for time synchronization via a network; and circuitry connected to the time master via the network, wherein the circuitry includes a local clock and is configured to: periodically determine, for every two or more receptions of the synchronization signal via the network, a communication timing so that a frequency of the communication timing is reduced from a transmission frequency of the synchronization signal; periodically perform, in accordance with the communication timing periodically determined with the reduced frequency, data exchange with the time master including transmission of a response signal to the synchronization signal; acquire an offset of the local clock with respect to the time master based on a result of the data exchange; correct the local clock in accordance with the offset; and control a machine based on the corrected local clock.