Bus monitor unit
View Patent ↗A central node for a data bus system includes a bus monitor unit with receiver means for registering signals on the data bus, and evaluation means which detect incorrect communication on the data bus and at least temporarily block communication by the user that causes the incorrect communication or compensate the incorrect communication of a user which is triggered by the interference influences. The bus monitor unit includes timing means which are triggered according to time patterns for the transmission of each user of the data bus, in order to detect an incorrect communication of a user if the latter transmits outside the time provided for it. The bus monitor unit is integrated into the central bus node and a plurality of bus branches of different users are combined at the central node so that the bus monitor unit can check a plurality of users for incorrect communication. In order to increase reliability, in addition to the bus monitor unit, a diagnostic unit is integrated into the central node. The latter monitors the bus monitor unit in terms of regular retriggering in response to the time patterns, so that the bus monitor unit can be deactivated in the absence of retriggering.
1. A central node for a data bus system having a bus monitor unit with receiver means for registering signals on the data bus, and evaluation means for at least temporarily blocking communication by a bus user which causes faulty communication on the bus, or for compensating a faulty communication that is triggered by interference influences, wherein:
the bus monitor unit has timing means which are triggered according to time patterns for transmission by each user of the data bus, to detect a faulty communication of a particular user if the particular user transmits outside a time provided for it;
the bus monitor unit is integrated into the central node;
a plurality of bus branches of different users are combined at the central node, so that the bus monitor unit can check a plurality of users for incorrect communication;
in addition to the bus monitor unit the central node has integrated therein,
a diagnostic unit that monitors regularity of retriggering of the bus monitor unit according to the time patterns, whereby the bus monitor unit can be deactivated in the absence of retriggering; and
a configuration means for configuring the communication for each user in accordance with a provided configuration list, whereby, in the event of a fault, each user is either released or blocked to further communication;
the time patterns for transmission on the data bus are settable via the central node, to trigger the bus monitor unit in response to the various transmission slots for the users on the data bus;
the diagnostic unit includes means for intermittently switching the bus monitor from an active state to an inactive state in particular time periods, to permit asynchronous communication on the data bus during such time periods.
2. The apparatus according to claim 1 , wherein:
the diagnostic unit includes a watchdog which is connected to the timing means, and to which signals for regular retriggering of the bus monitor unit are fed;
the watchdog is connected via a control line to the bus monitor unit and blocks its operation in the absence of retriggering.
3. The apparatus according to claim 1 , wherein the bus monitor is integrated in a node computer housing, together with the central node and the diagnostic unit.
4. The apparatus according to claim 1 , wherein:
the bus monitor unit is connected via an interface to a communications computer of the central node, which loads or calculates the time patterns.
5. The apparatus according to claim 4 , wherein the timing means is periodically triggerable according to said time patterns.
6. The apparatus according to claim 1 , wherein the timing means has a watchdog which checks cyclical synchronization of the timing means according to said time patterns, and provides a fault message when it fails to occur.
7. The apparatus according to claim 6 , wherein the watchdog blocks the bus monitor unit when there is a fault message relating to intervention into the bus communication.
8. The apparatus according to claim 1 , wherein the central bus node comprises a star coupler of a data bus having one of a star shape and a cascaded star shape.
9. The apparatus according to claim 1 , wherein the blocking of communication is performed during one of an initialization and cyclically during operation.
10. A central node for a data bus system having a bus monitor unit with receiver means for registering signals on the data bus, and evaluation means for at least temporarily blocking communication by a bus user that causes faulty communication on the bus, or for compensating a faulty communication that is triggered by interference influences, wherein:
the bus monitor unit has timing means which are triggered accordance to time patterns for transmission by each user of the data bus, to detect a faulty communication of a particular user if the particular user transmits outside a time provided for it;
the bus monitor unit is integrated into the central node;
a plurality of bus branches of different users are combined at the central node, so that the bus monitor unit can check a plurality of users for incorrect communication; and
in addition to the bus monitor unit, the central node includes a diagnostic unit integrated therein, said diagnostic unit monitoring regularity of retriggering of the bus monitor unit according to the time patterns, whereby the bus monitor unit can be deactivated in the absence of retriggering; and
the diagnostic unit includes means for intermittently switching the bus monitor from an active state to an inactive state in particular time periods, to permit asynchronous communication on the data bus during such time periods.
11. The apparatus according to claim 10 , wherein:
the diagnostic unit includes a watchdog which is connected to the timing means, and to which signals for regular retriggering of the bus monitor unit are fed; and
the watchdog is connected via a control line to the bus monitor unit and blocks its operation in the absence of retriggering.
12. The apparatus according to claim 10 , wherein the bus monitor is integrated in a node computer housing, together with the central node and the diagnostic unit.
13. The apparatus according to claim 10 , wherein the bus monitor unit is connected via an interface to a communications computer of the central node, which loads or calculates the time patterns.
14. The apparatus according to claim 10 , wherein the timing means has a watchdog which checks cyclical synchronization of the timing means according to said time patterns, and provides a fault message when it fails to occur.
15. A data bus system comprising a node that includes a star coupler by which branches of said data bus system are connected in a star configuration, a bus monitor unit with receiver means for registering signals on the data bus system, and evaluation means for at least temporarily blocking communication by a bus user of said system that causes faulty communication on the bus, or for compensating a faulty communication that is triggered by interference influences, wherein:
said central node is in the form of a gateway at which bus branches of at least two different data bus systems converge;
the bus monitor unit has timing means which are triggered according to time patterns for transmission by each user of said at least two different data bus systems, to detect and block a faulty communication of a particular user if the particular user transmits outside a time provided for it;
the bus monitor unit is integrated into a central node;
a plurality of said branches which are connected to different users are combined at said central node via said star coupler, so that the bus monitor unit can check said plurality of users for incorrect communication; and
in addition to the bus monitor unit, a diagnostic unit is integrated into the central node, said diagnostic unit monitoring regularity of retriggering of the bus monitor unit according to the time patterns, whereby the bus monitor unit can be deactivated in the absence of retriggering.
16. The apparatus according to claim 15 , wherein:
the diagnostic unit includes a watchdog which is connected to the timing means, and to which signals for regular retriggering of the bus monitor unit are fed; and
the watchdog is connected via a control line to the bus monitor unit and blocks its operation in the absence of retriggering.
17. The apparatus according to claim 15 , wherein the bus monitor is integrated in a node computer housing, together with the central node and the diagnostic unit.
18. The apparatus according to claim 15 , wherein the bus monitor unit is connected via an interface to a communications computer of the central node, which loads or calculates the time patterns.
19. The apparatus according to claim 15 , wherein the timing means has a watchdog which checks cyclical synchronization of the timing means according to said time patterns, and provides a fault message when it fails to occur.