Method for monitoring a communication media access schedule of a communication controller of a communication system

One of a number of nodes connected to a communication media, wherein messages are transmitted among the nodes across the communication media based on a cyclic time triggered communication media access scheme, the node comprising:

• a communication controller;
• and
• means for monitoring the communication media access schedule of said communication controller, in which means a priori knowledge about possible deviations from the communication media access schedule during startup of the communication is stored and means for making use of said a priori knowledge in order to distinguish between an allowed deviation and a forbidden deviation caused by a failure of said communication controller during startup of the communication,
• the communication controller being arranged to transmit a first trigger signal (ARM) to a bus guardian assigned to that communication controller 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 the communication controller is further arranged to transmit a further trigger signal (ARM) within a further expectation window, which further tripper signal (ARM) defines a beginning of a new cycle of the communication media access scheme,
• wherein the communication controller is further arranged to define each of a number of further expectation windows 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.

A communication system comprising:

• a communication controller;
• and
• nodes connected to said communication media,
• wherein messages are transmitted among said nodes across said communication media based on a cyclic time triggered communication media access scheme,
• each node having a communication controller and a monitoring unit, for monitoring a communication media access schedule of said communication controller,
• wherein said monitoring unit has a priori knowledge about possible deviations from the communication media access schedule during startup of the communication and said monitoring unit has means for making use of said a priori knowledge in order to distinguish between an allowed deviation and a forbidden deviation caused by a failure of said communication controller during startup of the communication 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 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 the communication controller is further arranged to transmit a further trigger signal (ARM) within a further expectation window, which further trigger signal (ARM) defines a beginning of a new cycle of the communication media access scheme,
• wherein the communication controller is further arranged to define each of a number of further expectation windows 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.

A computer readable storage medium storing a program having computer executable instructions that when executed by a processor cause to execute 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 across 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 tripper 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.