Diagnostic system and method for network synchronized time in safety applications
US12355553B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 2022 |
| Grant date | Jul 8, 2025 |
| Priority date | — |
| Expiry date | Dec 22, 2043 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2012/4026
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
To improve integrity of time synchronization, a node in a safety rated system verifies that its clock remains synchronized to another clock. Two adjacent, time-synchronized nodes transmit diagnostic messages to each other at an agreed upon interval and generate timestamps when the diagnostic message is received from the other node. The nodes then transmit their respective timestamp back to the sending node. Clock drift is detected by comparing a difference between the two timestamps at which the messages were received against a threshold. To avoid accidental detection of clock drift, a difference in transmission delays between the two nodes is stored in a FIFO buffer. Each node monitors the average of the data in the FIFO buffer. If the average deviates from the target value by too great a value, then the node determines the values of the clocks have skewed beyond an acceptable range and generates a fault condition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.