The core of adjusting the PTP synchronization interval and timeout is balancing accuracy and network load. For dual-sensor redundancy comparison scenarios, standardized adjustment parameters and steps are provided:
I. Parameter Meaning Explanation
|
Parameter |
Function |
Impact on Dual-Sensor Scenarios |
|
Synchronization Interval (Announce Interval/Sync Interval) |
Frequency at which the master clock sends synchronization messages. |
Shorter intervals result in higher synchronization accuracy, but also higher network load. |
|
Timeout |
How long after the slave clock loses a synchronization message is a disconnection considered. |
Too short a timeout leads to frequent disconnections and resynchronization; too long a timeout prevents timely detection of anomalies. |
II. Recommended Parameters for Dual-Sensor Scenarios (Directly Apply)
Use the corresponding parameters directly according to the acquisition type; no additional debugging is required:
|
Application Scenarios |
Sync Interval |
Announce Interval |
Timeout |
|
Ordinary Industrial Low-Speed Acquisition (≤50Hz) |
1 second |
8 seconds |
3 times Announce Interval = 24 seconds |
|
Medium-High-Speed Acquisition (50Hz~1kHz) |
125 milliseconds |
2 seconds |
3x Announce Interval = 6 seconds |
|
High-frequency, high-precision acquisition (>1kHz) |
62.5 milliseconds |
1 second |
3x Announce Interval = 3 seconds |
General simplified solution: Regardless of the scenario, simply set the Sync interval to 1 second and the timeout to 24 seconds to meet the requirements of 90% dual-sensor redundancy comparison, achieving optimal accuracy and load balance.
III. Specific Adjustment Steps (General Process)
Open the device's PTP configuration interface and find the "Sync Interval" setting.
Enter the corresponding recommended value, usually in log2 (seconds). For example:
A 1-second interval corresponds to 0 (because 2⁰=1)
A 125-millisecond interval corresponds to -3 (because 2⁻³=0.125)
A 62.5-millisecond interval corresponds to -4 (because 2⁻⁴=0.0625)
If the device directly supports millisecond/second input, simply enter the value.
Find the "Announce Interval" setting and set it to 8 times the Sync interval:
Sync interval 1 second → Announce interval 8 seconds, corresponding to a log2 value of 3.
Find the "Announce" setting... Set the "Timeout" setting to 3 times the Announce interval and apply the changes immediately.
IV. Post-Adjustment Verification
After adjustment, wait 2 minutes for resynchronization and check the clock offset:
If the offset fluctuation is smaller than before adjustment, the parameters are appropriate.
If network load exceeds device bandwidth (rarely occurs), halve the synchronization interval (lengthen the interval).
Notes
Do not set the synchronization interval too short (e.g., less than 1ms), as this will excessively consume network bandwidth and lead to decreased packet collision accuracy. The timeout must be set to 3 times the Announce interval; this is the recommended value in the PTP protocol specification to avoid misjudging connections.
