Method for monitoring a communication media access schedule of a communication controller of a communication system
First Claim
1. 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.
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Abstract
The invention refers to a method for monitoring a communication media access schedule of a communication controller (5) of a communication system (1) by means of a bus guardian (6). The communication system (1) comprises a communication media (2) and nodes (3) connected to the communication media (2). Each node (3) comprises a communication controller (5) and a bus guardian (6) assigned to the communication controller (5). Messages are transmitted among the nodes (3) across the communication media (2) based on a cyclic time triggered communication media access scheme. In order to provide a mechanism which allows the bus guardian (6) to monitor the communication media access scheme of the communication controller (5) even during startup of the communication it is suggested, that the bus guardian (6) has a priori knowledge about possible deviations from the communication media access schedule during startup of the communication and that the bus guardian (6) during startup makes use of the a priori knowledge to distinguish between an allowed deviation and a forbidden deviation caused by a failure of the communication controller (5).
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Citations
10 Claims
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1. 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. - View Dependent Claims (2, 3, 4, 5, 6)
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7. 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:
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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.
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8. A communication system comprising:
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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.
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9. 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. - View Dependent Claims (10)
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Specification