Network Time Synchronization With Stable Interrupt Cycles
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Solution Overview
Problem
Existing time synchronization methods in networks can lead to interruptions in work processes due to inaccuracies in clock synchronization, especially when network participants experience different frequency rates due to physical influences like temperature variations.
Innovation Solution
The method involves determining a time offset between the master and slave periods upon receipt of a synchronization message, then performing a time jump to compensate for the entire time offset without disrupting ongoing work processes. Subsequent adjustments to the trigger times of interrupts ensure that the cycle duration remains consistent with minimal deviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional time synchronization methods are used to align slave time with master time, then clock synchronization accuracy is improved, but interruptions in work processes occur due to frequency variations
Solution Approach 1:
The patent applies preliminary action by calculating and storing the nominal cycle time of interrupts before time synchronization occurs. This allows the system to anticipate and compensate for potential disruptions caused by time jumps, ensuring that interrupt cycles remain consistent even when slave time is adjusted to match master time.
Solution Approach 2:
The patent changes the parameter of interrupt timing by adapting the trigger times of interrupts after synchronization. Specifically, it adjusts the actual cycle times of interrupts to match the nominal cycle time, compensating for the time offset introduced during synchronization and maintaining work process continuity.
2Measurement precision
If a time jump is performed to compensate for the entire time offset, then synchronization accuracy is improved, but the cycle duration of interrupts may be disrupted
Solution Approach 1:
The patent implements feedback by calculating the actual cycle time of each interrupt after synchronization and comparing it with the nominal cycle time. Based on this comparison, it adapts subsequent interrupt trigger times to ensure that the actual cycle duration matches the expected nominal duration, thereby stabilizing the interrupt rhythm despite the time jump.
3Measurement precision
If frequent synchronization messages are sent to maintain accurate time alignment, then time synchronization precision is improved, but network traffic and processing overhead increase
Solution Approach 1:
The patent applies partial action by performing time synchronization only when necessary, rather than continuously adjusting time. It calculates the time offset and applies a corrective time jump only when the offset exceeds a threshold, reducing the frequency of synchronization operations while maintaining sufficient time alignment precision for interrupt stability.
Data Source
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AI summary
The present invention describes a method for time synchronization between at least one master (2) and at least one slave (3) in a network (1), wherein the at least one master (3) specifies a master time (tM) and sends at least one synchronization message (D) containing the master time (tM) to the at least one slave (3) via the network (1). The at least one slave (3), on which a slave time (ts) is running, uses the synchronization message (D) to align the slave time (ts) with the master time (tM) by means of synchronization, wherein the at least one slave (3) is an interrupt-capable network participant (8', 8") of the network (1) and uses a timer (6) which accesses the slave time (ts) to generate at least one interrupt (I) repeating with a predetermined cycle duration (tC) at a trigger time (tI) synchronized to the slave time (tS).Upon arrival of a synchronization message (D), the slave (3) calculates a time offset (Δt) between the master time (tM) and the slave time (tS). From this time offset (Δt), a time fraction (Δt1) is determined, which corresponds to an integer multiple of the predefined cycle duration (tc) of the at least one interrupt (I). An interrupt offset (ΔtC) is then calculated from the time fraction (Δt1) and the time offset (Δt). A synchronization unit (5.2) in the slave (3) executes at least one time jump (TJ) to compensate for the time offset (Δt). The first trigger time (tI+1) of the at least one interrupt (I) following the at least one time jump (TJ) is set such that it is offset from the last trigger time (tI) before the at least one time jump (TJ) by the predefined cycle duration (tC).A number (N) of trigger times (tI+n) of the at least one interrupt (I) following the time jump (TJ) are then shifted in time by an adjustment period (AD), wherein the adjustment period (AD) for each of the number (N) of trigger times (tI+n) following the time jump (TJ) is chosen from a time range such that the adjustment period (AD) is at most the interrupt offset (ΔtC) and at most a predefined time deviation (dt), and that the sum of all adjustment periods (AD) for the number (N) of trigger times (tI+n) following the time jump (TJ) corresponds to the interrupt offset (ΔtC) taking into account a predefined tolerance value (G).