Supervising arrangement
A hierarchical fault handling system and method based on filtering data regarding entities in the system and coordinating said filtered data in order to determined if an entity is considered faulty or not. The result for all entities is coordinated in a system fault coordinating means ( 17 ) which makes the overall decision if the system considered to be faulty or not.
1. A supervising system for supervising the function of an assembly comprising a number of interworking parts, said system comprising
At least a first detector for detecting a physical property of an entity of the system and providing measurement data about the physical property;
At least a first determining means for determining the status of said entity;
said supervising system comprising filter means arranged to receive measurement data from the at least first detector, filter said measurement data and output a signal indicating if said entity is faulty in dependence of said filtered measurement data; and
in that the determining means is arranged to receive said output signal from a least a first and a second filter means, co-ordinate said output signals and, on the basis of said co-ordination, determine whether a fault report should be generated for the entity.
2. A supervising system according to claim 1 , wherein the filter means are arranged to filter the measurement data on the basis of comparison with at least one threshold.
3. A supervising system according to claim 1 , further comprising at least a first action means for taking action to correct the fault in dependence of the status of said entity.
4. A supervising system according to claim 1 , comprising a system fault determining means arranged to receive from at least two entity fault determining means reports regarding the status of at least two entities supervised by the at least two entity fault determining means and determine, on the basis of said reports a fault status for the system.
5. A supervising system according to claim 4 , wherein the system fault determining means is arranged to check periodically all overall entity states X and determine the fault status of the system on the basis of these checks, where X indicates whether the entity is faulty or not and the absolute value of X indicates the reliability of the state.
6. A supervising system according to claim 4 , wherein the system fault determining means is arranged to request from each fault co-ordination means a report on the status of the entity or entities supervised by it.
7. A supervising system according to claim 6 , wherein the system fault determining means is arranged to request said report when a fault has been raised or ceased for at least one entity.
8. A supervising system according to claim 1 , wherein the filter means comprise at least one filter that is arranged to receive and filter analogue measurement data.
9. A supervising system according to claim 8 , wherein the filter means comprises a median filter arranged to receive an analogue value from a detector, calculate the median value of a number of such analogue values and pass the median value to a low-pass filter arranged to filter the median value and output the filtered median value is output to the limit checker arranged to check the filtered value received from the low-pass filter against at least one threshold, to determine if a fault is to be raised, or ceased, respectively.
10. A supervising system according to claim 9 , further comprising a step limiter arranged to receive the median value from the median filter, determine the difference between said median value and a previous median value and, if said difference is greater than a maximum raising step or a maximum decreasing step, adjust the median value to a value to keep the step within allowed limits.
11. A supervising system according to claim 9 , wherein the low-pass filter is arranged to filter the median value.
12. A supervising system according to claim 9 , wherein the limit checker is arranged to check the filtered value against an upper and a lower threshold so that hysteresis can be obtained.
13. A supervising system according to claim 1 , wherein the filter means comprises at least one filter that is arranged to receive and filter digital measurement data.
14. A supervising system according to claim 13 , wherein the filter means is arranged to filter data in the form of binary values, and comprises at least one buffer arranged to store the most recent samples of the binary value and determine, for each sample, whether or not it indicates a fault, and a limit checker connected to the buffer arranged to compare the number of samples indicating a fault to at least one threshold to determine if an alarm should be raised or ceased.
15. A supervising system according to claim 14 , wherein the limit checker is arranged to compare the number of samples indicating a fault to an upper and a lower threshold to obtain hysteresis.
16. A supervising system according to claim 1 , wherein the filter means comprises at least two buffers at least two limit checkers each connected to one of the buffers and voting means arranged to determine, on the basis of the output from all limit checkers if a fault should be raised or ceased.
17. A supervising system according to claim 1 , wherein the filter means comprises means for filtering received measurement data on the basis of at least two different sets of filter constants, to produce at least two different logical values and means for determining a logical output signal from the filter means.
18. A supervising system according to claim 1 , characterized in that it is arranged to supervise a telecommunications system.
19. A supervising system according to claim 1 , wherein parameters controlling the function of said filter means are stored in the system during manufacturing.
20. A supervising system according to claim 1 , wherein parameters controlling the function of said filter means are comprised in a software application package.
21. A supervising system according to claim 1 , wherein parameters controlling the function of said filter means are comprised in configuration data created for a particular site.
22. A supervising system according to claim 1 , wherein the system fault co-ordinator is arranged to order a dump of some or all fault filters in the system to be stored in persistent memory, said dump containing state variables for fault filters.
23. A supervising system according to claim 22 , wherein the dump further comprises a traceback buffer containing the last minutes of detector data input to each fault filter.
24. A method for supervising the function of an assembly comprising a number of interworking parts, comprising the following steps:
defining at least one entity of the system that is to be supervised;
detecting at least one physical property of the entity as at least one measured value;
filtering the at least one measured value;
determining whether or not the entity is faulty on the basis of the filtered value.
25. A method according to claim 24 , wherein the filter is arranged to output a logical indication of whether or not the measured value indicates that the entity is considered faulty.
26. A method according to claim 24 further comprising the step of determining whether or not the entity is faulty on the basis of several filtered values output from several filters as a result of the filtering of several measured values each corresponding to a physical property of the entity.
27. A method according to claim 26 wherein a decision on whether or not an entity is faulty is determined on the basis of a weighted sum of the output from several filters.
28. A method according to claim 24 , wherein a fault status for the entire assembly is determined on the basis of decisions regarding several entities in the assembly.
29. A method according to claim 24 , wherein the step of filtering the at least one measured value comprises filtering the value on the basis of at least two different sets of filter constants to produce at least two different logical values and means for determining a logical output signal from the filter means.
30. A method according to claim 23 , further comprising the step of ordering a dump of some or all fault filters in the system to be stored in persistent memory, said dump containing state variables for fault filters.