Time-synchronization of local clocks in units linked together in safety-critical automation bus systems, whereby synchronization packets are transmitted around ring buses with synchronization based on time-of-flight measurements

摘要

Method for time-synchronization of local clocks in a circular transmission medium, especially an automation bus linking a number of bus units, is based on time-of-flight measurement. According to the method synchronization is achieved by transmission of synchronization packets around the bus. A single ring bus solution is possible in which sequential packets are transmitted in opposite directions or a double bus solution in which packets are transmitted in the same direction on each bus while each bus transmits in the opposite direction.