US5949676A
Expired / Lapsed
US
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Method and system for diagnosing the behavior of a machine controlled by a discrete event control system
Assignee: Allen Bradley Co LLC
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Filing: 1997-07-30
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Granted: 1999-09-07
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Expires: 2017-07-30
Abstract
Abstract A method and system for diagnosing the behavior of a machine which performs a discrete event process. A diagnostic engine observes occurrences of discrete events to detect timing patterns. A statistical analysis is performed on repetitions of the timing patterns, thus providing the basis for defining diagnostic rules. The rules are updated in real time and are subject to a rule competition procedure in which only the most precise and efficient rules are selected. Further occurrences of discrete events are evaluated relative to the diagnostic rules to identify and predict malfunctions of the machine.
Inventors
- 👤 Richard K. Elsley
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 22:13
CPC Classifications
G; G05; G05B; G05B23/00; G05B23/02; G05B23/0205; G05B23/0218; G05B23/0224; G05B23/0227; G05B23/0229; G05B23/024
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
129 words
A system for developing diagnostic rules for diagnosing the behavior of a machine performing a process with discrete events, the system comprising: a main processor; and a plurality of control elements in communication with the main processor and the machine, the control elements detecting the discrete events and communicating them to the main processor, wherein the main processor is configured (1) to detect a timing pattern in the occurrences of the discrete events, the timing pattern including a trigger event, a result event, and a time interval between the trigger and result events, (2) to define a diagnostic rule based on a statistical analysis of repetitions of the timing pattern, and (3) to update the diagnostic rule in real time based on a detected change in the timing pattern.
Claim 2
Independent Claim
129 words
A system for developing diagnostic rules for diagnosing the behavior of a machine performing a process with discrete events, the system comprising: a main processor; and a plurality of control elements in communication with the main processor and the machine, the control elements detecting the discrete events and communicating them to the main processor, wherein the main processor is configured (1) to detect a timing pattern in the occurrences of the discrete events, the timing pattern including a trigger event, a result event, and a time interval between the trigger and result events, (2) to define a diagnostic rule based on a statistical analysis of repetitions of the timing pattern, and (3) to update the diagnostic rule in real time based on a detected change in the timing pattern.
Claim 3
Dependent Claim
32 words
The system as recited in claim 1, wherein the statistical analysis includes calculating a mean time interval between the trigger and result events and a standard deviation from the mean time interval.
Claim 4
Dependent Claim
45 words
The system as recited in claim 2, wherein the main processor calculates a ratio of the standard deviation to the mean time interval and defines the diagnostic rule if the magnitude of the ratio is substantially equal to or less than a predetermined maximum magnitude.
Claim 5
Dependent Claim
34 words
The system as recited in claim 2, wherein the main processor defines the diagnostic rule if the duration of the mean time interval is substantially equal to or less than a predetermined maximum duration.
Claim 6
Dependent Claim
33 words
The system as recited in claim 2, wherein the main processor defines the diagnostic rule if the magnitude of the standard deviation is substantially equal to or less than a predetermined maximum deviation.
Claim 7
Dependent Claim
29 words
The system as recited in claim 1, wherein the detected change in the timing pattern is a duration change in the time interval between the trigger and result events.
Claim 8
Dependent Claim
82 words
The system as recited in claim 1, wherein the detected change in the timing pattern is the occurrence of the result event a second time interval after a second trigger event, and the main processor (1) defines a second diagnostic rule based on a statistical analysis of repetitions of a second timing pattern including the second trigger event, the result event and the second time interval, and (2) updates the diagnostic rule by replacing the diagnostic rule with the second diagnostic rule.
Claim 9
Dependent Claim
80 words
The system as recited in claim 7, wherein the statistical analysis of the repetitions of the timing pattern includes calculating a mean time interval between the trigger event and the result event and a standard deviation from the mean time interval, and the statistical analysis of the repetitions of the second timing pattern includes calculating a second mean time interval between the second trigger event and the result event and a second standard deviation from the second mean time interval.
Claim 10
Dependent Claim
36 words
The system as recited in claim 8, wherein the main processor updates the diagnostic rule by replacing the diagnostic rule with the second diagnostic rule if the second standard deviation is smaller than the standard deviation.
Claim 11
Dependent Claim
67 words
The system as recited in claim 8, wherein the main processor determines a first ratio of the standard deviation to the mean time interval and a second ratio of the second standard deviation to the second mean time interval, and the main processor updates the diagnostic rule by replacing the diagnostic rule with the second diagnostic rule if the second ratio is smaller than the first ratio.
Claim 12
Dependent Claim
60 words
The system as recited in claim 1, wherein the machine has a first and second machine state during which discrete events occur, and wherein the timing pattern is a common timing pattern occurring during at least both the first and second machine states, and the diagnostic rule is based on a statistical analysis of repetitions of the common timing pattern.
Claim 13
Dependent Claim
15 words
The system as recited in claim 1, wherein the diagnostic rules are symmetric diagnostic rules.
Claim 14
Dependent Claim
56 words
The system as recited in claim 1, further comprising a communication link and a plurality of control modules coupled to the communication link to communicate the occurrences of the discrete events to the main processor, wherein each control module is configured to detect the transitions between the states of at least one of the control elements.
Claim 15
Dependent Claim
38 words
The system as recited in claim 1, wherein the main processor is further configured to evaluate the detected change in the timing pattern relative to the diagnostic rule to identify a malfunction in the behavior of the machine.
Claim 16
Dependent Claim
41 words
The system as recited in claim 1 wherein the main processor is configured further (4) to evaluate in real time the occurrences of the discrete events relative to the diagnostic rule to identify a malfunction in the behavior of the machine.
Claim 17
Dependent Claim
34 words
The system as recited in claim 15, wherein the real time statistical analysis includes calculating a mean time interval between the trigger and result events and a standard deviation from the mean time interval.
Claim 18
Dependent Claim
38 words
The system as recited in claim 16, wherein the main processor identifies the malfunction when the result event does not occur after the trigger event within the mean time interval plus or minus at least one standard deviation.
Claim 19
Dependent Claim
33 words
The system as recited in claim 16, wherein the real time statistical analysis further includes calculating an updated mean time interval for each timing pattern based on further repetitions of the timing pattern.
Claim 20
Dependent Claim
39 words
The system as recited in claim 18, wherein the main processor identifies the malfunction when the result event does not occur after the trigger event within the updated mean time interval plus or minus at least one standard deviation.
Claim 21
Dependent Claim
19 words
The system as recited in claim 15, wherein the main processor identifies the malfunction when an unexpected event occurs.
Claim 22
Dependent Claim
28 words
The system as recited in claim 15, wherein the system further comprises a display in communication with the main processor to provide visible indicia representative of the malfunction.
Claim 23
Dependent Claim
31 words
The system as recited in claim 15, wherein the main processor is further configured to update the diagnostic rule in real time based on a detected change in the timing pattern.
Claim 24
Independent Claim
119 words
A method for developing diagnostic rules for diagnosing the behavior of a machine having a plurality of control elements which cooperate to perform a plurality of discrete events the method comprising the steps of: monitoring occurrences of discrete events associated with the plurality of control elements; detecting a timing pattern in the occurrences of the discrete events, the timing pattern including a trigger event, a result event and a time interval between the trigger and result events; performing a statistical analysis of repetitions of the timing pattern; defining a diagnostic rule based on the statistical analysis; detecting in real time a change in the timing pattern; and updating in real time the diagnostic rule based on the detected change.
Claim 25
Independent Claim
119 words
A method for developing diagnostic rules for diagnosing the behavior of a machine having a plurality of control elements which cooperate to perform a plurality of discrete events the method comprising the steps of: monitoring occurrences of discrete events associated with the plurality of control elements; detecting a timing pattern in the occurrences of the discrete events, the timing pattern including a trigger event, a result event and a time interval between the trigger and result events; performing a statistical analysis of repetitions of the timing pattern; defining a diagnostic rule based on the statistical analysis; detecting in real time a change in the timing pattern; and updating in real time the diagnostic rule based on the detected change.
Claim 26
Dependent Claim
27 words
The method as recited in claim 23, wherein performing the statistical analysis includes calculating a mean time interval and a standard deviation from the mean time interval.
Claim 27
Dependent Claim
48 words
The method as recited in claim 24, further comprising: calculating a ratio of the standard deviation to the mean time interval; comparing the magnitude of the ratio to a predetermined maximum magnitude; and rejecting the diagnostic rule if the magnitude of the ratio exceeds the predetermined maximum magnitude.
Claim 28
Dependent Claim
40 words
The method as recited in claim 24, further comprising: comparing the duration of the mean time interval to a predetermined maximum duration; and rejecting the diagnostic rule if the duration of the mean time interval exceeds the predetermined maximum duration.
Claim 29
Dependent Claim
40 words
The method as recited in claim 24, wherein the detected change in the timing pattern is a duration change in the time interval, and updating the diagnostic rule includes calculating an updated mean time interval based on the duration change.
Claim 30
Dependent Claim
76 words
The method as recited in claim 23, wherein the detected change in the timing pattern is the occurrence of the result event a second time interval after a second trigger event, thereby defining a second timing pattern, and updating the diagnostic rule includes: performing a second statistical analysis of repetitions of the second timing pattern; defining a second diagnostic rule based on the second statistical analysis; and replacing the diagnostic rule with the second diagnostic rule.
Claim 31
Dependent Claim
86 words
The method as recited in claim 28, wherein performing the statistical analysis includes calculating a mean time interval and a standard deviation from the mean time interval, performing the second statistical analysis includes calculating a second mean time interval and a second standard deviation from the second mean time interval, and replacing the diagnostic rule includes comparing the standard deviation to the second standard deviation and replacing the diagnostic rule with the second diagnostic rule if the second standard deviation is smaller than the standard deviation.
Claim 32
Dependent Claim
76 words
The method as recited in claim 23, wherein the machine has a first machine state for performing a first discrete event process and a second machine state for performing a second discrete event process, the method further comprising: selecting a common timing pattern occurring during at least both the first and second machine states; performing a statistical analysis of repetitions of the common timing pattern; and defining a common diagnostic rule based on the statistical analysis.
Claim 33
Dependent Claim
36 words
The method as recited in claim 23, further comprising evaluating the detected change in the timing pattern relative to the diagnostic rule and identifying a malfunction in the behavior of the machine based on the evaluation.
Claim 34
Dependent Claim
38 words
The method as recited in claim 23 further including the step of identifying in real time a malfunction in the behavior of the machine based on evaluating the occurrences of the discrete events relative to the diagnostic rule.
Claim 35
Dependent Claim
29 words
The method as recited in claim 32, wherein performing the real time statistical analysis includes calculating a mean time interval and a standard deviation from the mean time interval.
Claim 36
Dependent Claim
35 words
The method as recited in claim 33, wherein identifying the malfunction includes evaluating whether the result event occurs after the trigger event within the mean time interval plus or minus at least one standard deviation.
Claim 37
Dependent Claim
34 words
The method as recited in claim 33, wherein performing the real time statistical analysis further includes calculating an updated mean time interval for each timing pattern based on further repetitions of the timing pattern.
Claim 38
Dependent Claim
19 words
The method as recited in claim 32, wherein identifying the malfunction includes evaluating whether an unexpected event has occurred.
Claim 39
Dependent Claim
16 words
The method as recited in claim 32, further comprising displaying visible indicia representative of the malfunction.
Claim 40
Dependent Claim
25 words
The method as recited in claim 32, further comprising updating the diagnostic rule in real time based on a detected change in the timing pattern.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-09-06 | 2003-03-08 | 2003-09-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-09-06 | 2007-03-08 | 2007-09-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-09-06 | 2011-03-08 | 2011-09-07 | $7700.00 | Window Closed / Lapsed |