SYSTEM AND METHOD FOR MAINTAINING A COMMON SENSE OF TIME ON A NETWORK SEGMENT

摘要

The system (10) has control center (12), a time master device (16) and a plurality of distributed, time slave field devices (18) in synchronization with a master clock of the time master device. The time master device (16) periodically transmits a time distribution data unit. Each time slave field device (18) has a timer adjustment element (32), a fixed rate clock (36) and a variable clock (34). The timer adjustment element (32) calculates a frequency ratio between the master clock and the fixed rate clock and uses the frequency ratio to calculate adjustment coefficients to adjust a local sense of time for each field device, such that a time stamp of each field device is synchronized to the master clock.