Bus monitor unit

Abstract

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. 
     
     
       20. A method for monitoring data communications in a data bus system, the method comprising:
   monitoring data signals received via a data bus from one or more nodes, wherein the data bus operates in a synchronous mode having a time slot configuration;        detecting a faulty access by a node to the data bus; and        inactivating a bus monitor unit for a time period and switching the operation of the data bus from a synchronous mode to an asynchronous mode during the time period.     
     
     
       21. The method of  claim 20 , wherein each of the one or more nodes is assigned a designated time slot for accessing the data bus in accordance with the time slot configuration. 
     
     
       22. The method of  claim 21 , further comprising:
   detecting that the faulty access by the node to the data bus occurs in a time slot assigned to another node; and        blocking the data signals from all nodes in the time slot.     
     
     
       23. The method of  claim 21 , further comprising:
   detecting that the faulty access by the node to the data bus occurs in a time slot assigned to another node; and        blocking the data signals from the node causing the faulty access.     
     
     
       24. The method of  claim 21 , further comprising:
   detecting that the faulty access by the node to the data bus occurs in a time slot assigned to another node; and        removing from the data bus the data signals of the node causing the faulty access by filtering the data signals received via the data bus.     
     
     
       25. The method of  claim 21 , wherein monitoring of the data signals is triggered by a triggering signal in according with the time slot configuration. 
     
     
       26. The method of  claim 21 , wherein the designated time slot is assigned to each of the one or more nodes in a cyclical time pattern. 
     
     
       27. An apparatus for monitoring data communications in a data bus system, the apparatus comprising:
   a bus monitor unit for monitoring data signals received via a data bus from one or more nodes, wherein the data bus operates in a synchronous mode in accordance with a time slot configuration; and        a diagnostic unit for monitoring the bus monitor unit and for deactivating the bus monitor unit and switching the operation of the data bus from a synchronous mode to an asynchronous mode,        wherein the bus monitor unit is adapted to detect a faulty access by a node to the data bus when the data bus operates in the synchronous mode, and wherein the bus monitor unit and the diagnostic unit are integrated in a central node.     
     
     
       28. The apparatus of  claim 27 , wherein the diagnostic unit is adapted to adjust the time slot configuration. 
     
     
       29. The apparatus of  claim 27 , wherein each of the one or more nodes is assigned a designated time slot for accessing the data bus in accordance with the time slot configuration when the data bus operates in the synchronous mode. 
     
     
       30. The apparatus of  claim 29 , wherein the bus monitor unit detects that the faulty access by the node to the data bus occurs in a time slot assigned to another node and blocks the data signals from all nodes in the time slot. 
     
     
       31. The apparatus of  claim 29 , wherein the bus monitor unit detects that the faulty access by the node to the data bus occurs in a time slot assigned to another node and blocks the data signals from the node causing the faulty access. 
     
     
       32. The apparatus of  claim 29 , wherein the bus monitor unit detects that the faulty access by the node to the data bus occurs in a time slot assigned to another node and removes from the data bus the data signals of the node causing the faulty access by filtering the data signals received via the data bus. 
     
     
       33. The apparatus of  claim 29 , wherein the bus monitor unit is periodically triggered by a triggering signal in accordance with the time slot configuration. 
     
     
       34. The apparatus of  claim 27 , wherein the bus monitor unit is inactivated by the diagnostic unit in response to a malfunction of the bus monitor unit. 
     
     
       35. A method for monitoring data communications, the method comprising:
   receiving a first data signal via a first data bus;        converting the first data signal to a second data signal suitable for transmission on a second data bus, wherein the first data bus and the second data bus are interconnected by a central node and each of the first data bus and the second data bus has a different time slot configuration for allowing access of one or more user nodes; and        monitoring the first data bus and the second data bus for detecting a faulty access by a user node to one of the first data bus and the second data bus.     
     
     
       36. The method of  claim 35 , further comprising cyclically assigning a time slot to each of the one or more user nodes for transmitting data signals in accordance with the time slot configuration of the first data bus and the time slot configuration of the second data bus. 
     
     
       37. The method of  claim 35 , further comprising deactivating a bus monitor unit in the central node and switching the first data bus and the second data bus to an asynchronous mode. 
     
     
       38. A method for monitoring data communications, the method comprising:
   monitoring data signals received via a plurality of data buses, wherein the plurality of data buses are interconnected by a central node, wherein each of the plurality of data buses is connected to one or more nodes, and wherein each of the plurality of data buses has a different time slot configuration for allowing access by the one or more nodes;        converting the data signals received via one of the plurality of data buses to the data signals suitable for transmission on another one of the plurality of data buses; and        detecting a faulty access by a node to one of the plurality of data buses on the basis of the associated time slot configuration.     
     
     
       39. The method of  claim 38 , wherein at least one of the plurality of data buses is capable of operating in one of a synchronous mode and an asynchronous mode, the method further comprising switching the one of the plurality of data buses from the synchronous mode to the asynchronous mode. 
     
     
       40. The method of  claim 38 , wherein monitoring of the data signals is performed by a bus monitor unit residing in the central node, the method further comprising:
   detecting a faulty triggering of the bus monitor on the basis of the time slot configuration of the one of the plurality of data buses; and        deactivating the bus monitor unit.