Clock synchronisation on multiple TTCAN network channels

The Controller Area Network (CAN) is a well established control network for automotive and automation control applications. TimeTriggered Controller Area Network (TTCAN) is a recent development which introduces a session layer, for message scheduling, to the existing CAN standard, which is a two layer standard comprising of a physical layer and a data link layer. TTCAN facilitates network communication in a time-triggered fashion, by introducing a Time Division Multiple Access style communication scheme. This allows deterministic network behaviour, where maximum message latency times can be quantified and guaranteed. However, for safety-critical applications the market requires fault-tolerant control networks, which support spatial redundancy. The TTCAN standard does not support such built-in redundancy. This paper proposes a prototype design implementation for a synchronisation layer between two or more independent TTCAN network channels. This synchronisation layer can be used as a building block for network redundancy leading to a faulttolerant network architecture by introducing related and comparable message transmissions on multiple network channels. This leads to improved error tolerance and also facilitates increased bandwidth by running multiple synchronised TTCAN network channels in parallel. q 2004 Elsevier B.V. All rights reserved.