Patent ID: 7586953

Claim:
A method for monitoring a communication media access schedule of a communication controller in a communication system, the communication system comprising a communication media and nodes connected to the communication media, each node having a communication controller, wherein messages are transmitted among the nodes cross the communication media based on a cyclic time triggered communication media access scheme, the method comprising: a) providing a priori knowledge about possible deviations from the communication media access schedule during startup of the communication; and b) using said a priori knowledge during startup of the communication to distinguish between an allowed deviation and a forbidden deviation caused by a failure of the communication controller, wherein, during startup of the communication, the communication controller of one of the nodes transmits a first trigger signal (ARM) to a bus guardian assigned to that communication controller, wherein said first trigger signal (ARM) is transmitted at a beginning of a timeslot in a cycle of the communication media access scheme and a first expectation window is defined at an end of said timeslot in said cycle, wherein a further trigger signal (ARM) within a further expectation window defines a beginning of a new cycle of the communication media access scheme, wherein each of a number of further expectation windows is defined at a beginning of subsequent cycles of the communication media access scheme according to a parameter (ColdStartMax) defining a maximum number of cycles for which the communication controller is allowed to actively try to establish communication with a further communication controller of one of the other nodes of the communication system.