Today there is a great request of using automation networks in safety critical environments. Thus, such systems used in industrial and building automation have been enhanced with safety features derived from strict safety requirements specified in IEC 61508. One of the safety requirements to be met is the detection of hazardous events on the network such as the delay of a message. A safety measure to identify these hazardous events is the use of a timestamp within a safe protocol. However, a common time base among the nodes must be provided - by means of a network time synchronization mechanism. A centralized and decentralized approach was developed within the SafetyLon project. Realization of the concept and implementation in the producer/consumer model of SafetyLon is outlined.
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