(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2005/0246593 A1
`Littrell
`(43) Pub. Date:
`Nov. 3, 2005
`
`US 2005O246593A1
`
`(54) METHODS AND APPARATUS FOR
`PROVIDING ALARM NOTIFICATION
`
`(76) Inventor: Nathan Bowman Littrell, Gardnerville,
`NV (US)
`
`Correspondence Address:
`John S. Beulick
`Armstrong Teasdale LLP
`Suite 2600
`One Metropolitan Square
`St. Louis, MO 63102 (US)
`
`(21) Appl. No.:
`(22) Filed:
`
`10/827,201
`Apr. 19, 2004
`
`Publication Classification
`(51) Int. Cl." ..................................................... G06F 11/00
`(52) U.S. Cl. ................................................................ 714/48
`(57)
`ABSTRACT
`-
`A method for indicating an alarm condition in an industrial
`process includes measuring a parameter of the industrial
`process that varies over time and determining at least one
`parameter limit as a function of the parameter and also
`varying over time. The method further includes comparing
`the parameter to the parameter limit or limits and indicating
`an alarm condition when the parameter is outside of a bound
`Set by the parameter limit or limits when the parameter is
`compared to the parameter limit or limits.
`
`12
`
`14
`
`16
`
`10
`
`/
`
`MACHINE
`
`DATA
`ACOUSITION
`
`18
`
`2O
`
`COMPUTER
`
`DATABASE
`
`ALARM
`NDICATOR
`
`22
`
`24
`
`
`
`DECISION
`SUPPORT
`SOFTWARE
`
`STEP CHANGE .
`RULE
`
`Emerson Exhibit 1006
`Emerson Electric v. Ollnova
`IPR2023-00626
`Page 00001
`
`Page 00001
`
`

`

`Patent Application Publication Nov. 3, 2005 Sheet 1 of 3
`
`US 2005/0246593 A1
`
`
`
`
`
`NOLLISIQOOV/
`
`\/ LVCIENIHOVW
`
`?, "b?H#72
`
`-6| 39NWHO CHE LS
`
`
`
`BHVNA L-JOS
`
`
`
`}?OJ VOICINI
`
`OZ
`
`IPR2023-00626 Page 00002
`
`

`

`US 2005/0246593 Al
`
`PLL
`
`-LS3L
`
`cbL
`
`Patent Application Publication Nov. 3, 2005 Sheet 2 of 3
`
`
`
`
`
`ONOT-UUWHOSiNav'lv7331SONALSISYSd|HONONS|C"61JALIMBAZS
`ALIBAASS
`
`Lua||LINNOdS1dNvs9ONVAONYSLIT
`
`ZOL00}_/801vOl
`
`‘LS3LNOILVYENGIWNOISaLYST
`
`
`JINGOWLINN
`SNIWA‘LS3LTo3
`
`
`
`JO3dISLNOYSMO01“Y3SddN
`ATdNVSGITWAYaLaWveVd
`
`
`
`ANNOS0%"9'3)LNAWSYNSV3wa43naHolv
`
`(SINaWa1(dNWLSSWIVaLVO3ICGNIONI
`
`NYO
`
`
`
`uSTSNWEVS759Gi
`
`‘3OVYRAV
`
`OLLBOL
`
`IPR2023-00626 Page 00003
`
`IPR2023-00626 Page 00003
`
`
`
`
`
`

`

`Patent Application Publication Nov. 3, 2005 Sheet 3 of 3
`
`US 2005/0246593 A1
`
`
`
`s
`
`L.2
`C 9. 5 s.
`o
`E
`on E
`c\
`< c,
`
`IPR2023-00626 Page 00004
`
`

`

`US 2005/0246593 A1
`
`Nov. 3, 2005
`
`METHODS AND APPARATUS FOR PROVIDING
`ALARM NOTIFICATION
`
`BACKGROUND OF THE INVENTION
`0001. This invention relates generally to methods and
`apparatus that provide automatic notification of machine
`malfunctions.
`0002 Operators of significant equipment or processes
`need warning of equipment or proceSS malfunction. Such
`equipment can include machinery in power plants, oil refin
`eries, pipeline pumping Stations, manufacturing facilities,
`and any other appropriate applications. Known threshold
`based alarms can be used, and Such alarms provide an
`operator to use remedial tools and procedures to correct
`malfunction conditions. However, alarms based on param
`eter thresholds may not be timely enough to allow an
`operator to use Such tools and procedures optimally in all
`conditions.
`
`BRIEF DESCRIPTION OF THE INVENTION
`0003. Some configurations of the present invention there
`fore provide a method for indicating an alarm condition in
`an industrial process. The method includes measuring a
`parameter of the industrial process that varies over time and
`determining at least one parameter limit as a function of the
`parameter and also varying over time. The method further
`includes comparing the parameter to the parameter limit or
`limits and indicating an alarm condition when the parameter
`is outside of a bound set by the parameter limit or limits
`when the parameter is compared to the parameter limit or
`limits.
`0004. Also, some configurations of the present invention
`provide an apparatus for indicating an alarm condition in an
`industrial process. The apparatus includes a Sensor config
`ured to measure a parameter of the industrial process, a data
`acquisition System, and a computer. The apparatus is con
`figured to measure a time-varying parameter of the industrial
`proceSS and determine at least one parameter limit that is a
`function of the parameter and also varies over time. The
`apparatus is further configured to compare the parameter to
`the parameter limit or limits and indicate an alarm condition
`when the parameter is outside a bound Set by the parameter
`limit or limits when the parameter is compared to the
`parameter limit or limits.
`0005. In addition, some configurations of the present
`invention provide a medium having machine-readable
`instructions recorded thereon that are configured to instruct
`a computer to input a Sensed, time-varying parameter of an
`industrial process, determine at least one parameter limit as
`a function of the parameter and also varying over time. The
`instructions also are configured to instruct a computer to
`compare the parameter to the parameter limit or limits, and
`indicate an alarm condition when the parameter is outside of
`a bound set by the parameter limit or limits when the
`parameter is compared to the parameter limit or limits.
`0006. In yet another aspect of the present invention, there
`is provided a method for indicating an alarm condition in an
`industrial process. The method includes measuring a time
`varying parameter of the industrial process, latching the
`parameter and buffering the latched parameter in a FIFO
`(first-in, first-out) buffer, and determining statistical func
`
`tions of values of the buffered parameter stored in the FIFO
`buffer. The method further includes utilizing the determined
`Statistical functions to determine one or more alert limits,
`comparing value of the parameter to the one or more alert
`limits, and indicating an alarm dependent upon the param
`eter being outside a bound Set by the one or more alert limits.
`0007 Furthermore, some configurations of the present
`invention provide an apparatus for indicating an alarm
`condition in an industrial process. The apparatus is config
`ured to latch a varying parameter value of the industrial
`process and buffer Successive latched parameter values in a
`FIFO (first-in, first-out) buffer, determine statistical func
`tions of values of the buffered parameter stored in the FIFO
`buffer, and utilize the determined statistical functions to
`determine one or more alert limits. The apparatus is further
`configured to compare value of the parameter to the one or
`more alert limits, and indicate an alarm dependent upon the
`parameter being outside a bound Set by the one or more alert
`limits.
`0008 Some configurations of the present invention pro
`vide a medium having recorded thereon machine-readable
`instructions configured to instruct a computer to latch a
`varying parameter value of an industrial process and buffer
`successive latched parameter values in a FIFO (first-in,
`first-out) buffer and determine statistical functions of values
`of the buffered parameter stored in said FIFO buffer. The
`instructions are also configured to instruct a computer to
`utilize the determined Statistical functions to determine one
`or more alert limits, compare value of the parameter to the
`one or more alert limits, and indicate an alarm dependent
`upon the parameter being outside a bound Set by the one or
`more alert limits.
`0009 Configurations of the present invention allow early
`notification in accordance with behavior that might not trip
`a conventional threshold based alarm System. Additionally,
`configurations of the present invention avoid inappropriate
`alarms that may occur with conventional alarm systems that
`are not cognizant of machine State (e.g., whether the
`machine is running or not).
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0010 FIG. 1 is a block diagram of an industrial process
`in which a configuration of the present invention is provided
`to indicate an alarm when a step change in a parameter is
`encountered.
`0011 FIG. 2 is a block diagram representative of another
`configuration of the present invention.
`0012 FIG. 3 is a drawing showing a step change in a
`measured parameter.
`
`DETAILED DESCRIPTION OF THE
`INVENTION
`0013 Some configurations of the present invention track
`a measurand (e.g., vibration magnitude or phase) and, using
`the measurand, generate a result or raise an alarm when one
`or more configurable criteria are met (e.g., a statistically
`defined step change of the measurand). The invention also
`provides one or more time based criteria to qualify the data
`before raising an alarm. Some configurations permit a user
`to add additional preconditions to the rule to qualify data
`
`IPR2023-00626 Page 00005
`
`

`

`US 2005/0246593 A1
`
`Nov. 3, 2005
`
`before raising an alarm. AS used herein, a “measurand' is a
`measurable parameter of an industrial process.
`0.014.
`In some configurations 10 of the present invention
`and referring to FIG. 1, an industrial machine or apparatus
`12 (hereinafter “machine’) has an operating characteristic
`that is Subject to alarm conditions. A non-exhaustive list of
`Such machines 12 includes gas turbines, Steam turbines,
`electric generators, electric motors, pumps, gearboxes, and
`bearings. The operating characteristic Subject to alarm con
`ditions is Sensed by one or more Sensors 14. A non
`exhaustive list of operating conditions that can be Sensed by
`the one or more Sensors 14 include preSSure, temperature,
`position, acceleration, Velocity, power, current, and flow.
`Not all of these operating conditions are appropriate for each
`type of machine 12, but the choice of which one or more
`appropriate conditions are to be Sensed by the one or more
`Sensors 14 is left as a design choice. A data acquisition
`System 16 receives data from the one or more Sensors 14.
`Data acquisition System 16 can comprise, for example,
`networked hardware, a portable data collection unit, an
`internal computer or controller, or a data acquisition card in
`a computer System. Data acquisition System 16 is networked
`in Some configurations to a computer 18, which in Some
`configurations, includes or otherwise has access to a data
`base 20. Computer 18 executes a program comprising deci
`Sion Support Software or firmware 22, which, in turn,
`includes a step change rule module 24. In Some configura
`tions, database 20 contains variables that can be used for
`adjusting the sensitivity of step change rule module 24 in
`accordance with the type of machine 12 being monitored
`and the time-varying parameter or parameters measured by
`Sensor 14. Decision Support Software 22 and Step change
`rule 24 may be provided in the form of a computer readable
`medium (not shown in FIG. 1), such as a floppy diskette,
`CD-ROM, or DVD, having recorded thereon instructions
`configured to instruct computer 18 to perform the operations
`described below.
`0.015 Step change rule module 24 is configured to track
`a “normal” variation of a parameter. A Sudden change in this
`parameter will cause decision Support Software 22 to instruct
`computer 18 to raise an alarm indication. Alarm indication
`18, in Some configurations of the present invention, activates
`an audible or visual alarm device or a plurality or combi
`nation of alarm devices. Step change rule module 24 pro
`vides an upper and a lower bound for each parameter tracked
`by the one or more Sensors 14. For example, one time
`varying parameter is tracked utilizing limits D and E written
`as follows:
`D=average(A)+BxStd dev(A)+C, and
`E=average(A)-Bxstd dev(A)-C,
`0016 where:
`0017 A is a value associated with the parameter (for
`example, the parameter value itself, or a Scaled and/or
`possibly offset value of the parameter), which in Some
`configurations includes a Sample delay;
`0018) B is a constant multiplier;
`0019 C is a constant added to prevent a width of a
`window of acceptance between D and E from being
`narrowed to Zero as a result of the Standard deviation of
`A approaching or equaling Zero;
`
`0020 D is a time-varying upper acceptance limit; and
`0021 E is a time-varying lower acceptance limit; also
`0022 average(A) and std dev(A) are the average
`value of A over time and a Standard deviation of A over
`time, respectively.
`0023 The current (or, in some configurations, a delayed)
`Sample A is compared to upper and lower limits D and E,
`respectively. If A is outside of these limits, computer 18 is
`instructed to raise a Suitable alarm notification, Such as a
`displayed or audible alarm. The displayed or audible alarm
`need not be located on computer 18 itself, but may be an
`alarm raised in a portion of or throughout a manufacturing
`or power generation plant, for example, depending upon the
`nature of the parameter Abeing measured. In Some configu
`rations, parameter A is buffered (i.e., delayed) by a few
`Samples So that the limits do not open up immediately in
`response to a step change event, thus preventing a valid
`alarm condition from being triggered.
`0024.
`In some configurations of the present invention, the
`value of B is taken to be Zero, i.e., there is no Standard
`deviation term in the expressions for D or E.
`0025. In some configurations, the constant term C is zero,
`i.e., there is no constant term in the expressions for D or E.
`0026 In some configurations, the std dev() function is
`replaced by another Statistical measure of data variation.
`Replacement of the std dev() function is considered appro
`priate in case of data that is not normally distributed.
`0027. In some configurations of the present invention, the
`constant B is Set to 1. Also, in Some configurations of the
`present invention, a one-sided alarm limit is provided, i.e.,
`only either upper limit D or lower limit E is determined
`and/or used and alarms raised in accordance with only the
`one limit. And in Some configurations of the present inven
`tion the Average() function is replaced with another statis
`tical variable, for example, median() or mode().
`0028 Boundary D or E, or the combination of both, track
`a “normal' (in the Sense of acceptable) variation of a
`parameter Such as Vibration, temperature, power output, or
`any of the examples of variable A listed above, or other
`parameters. Any Sudden change will cause an alarm to be
`raised. Varying the size of a buffer used to determine
`averages (or other statistical variable) determines how
`quickly adjustment is made to level changes. Changing the
`value of B in various configurations affects the Sensitivity of
`the alarm to individual Sample variations. The constant C
`controls a minimum acceptable window size. Additionally,
`the sample rate (i.e., data collection frequency) affects alarm
`behavior in conjunction with Sample delay (or Sample buffer
`Size), as the product of the sample rate and Sample buffer
`Size determines the time period represented by data in the
`buffer.
`0029 Early warnings of step changes in the characteris
`tics of machine operation can be provided with Some con
`figurations of the present invention. For example, in Some
`configurations of the present invention, an average and
`standard deviation of a set of values stored in a FIFO buffer
`of variable (configurable) length. An upper and lower bound
`is determined by adding and Subtracting the Standard devia
`tion to the average value of the buffer. The standard devia
`tion value may be further modified by a multiplier depend
`
`IPR2023-00626 Page 00006
`
`

`

`US 2005/0246593 A1
`
`Nov. 3, 2005
`
`ing on application. A constant is also added to the Standard
`deviation value to prevent the tolerance window going to
`Zero when data is steady. An alarm is generated when the
`incoming value is outside of the tolerance bounds described
`above.
`0030 Thus, in some configurations 100 of the present
`invention and referring to FIG. 2, a parameter measurement
`102 is latched by latch 104 at suitable intervals, e.g., once
`every four Seconds, or at any other interval Suitable for
`observing and monitoring the industrial process. Latch 104
`feeds a FIFO (first-in, first-out) buffer 106, which holds a
`predetermined number of values of the latched parameter.
`For example, and not by way of limitation, Some configu
`rations of the present invention include a 20 element FIFO,
`which holds the last 20 latched values of the parameter.
`Other configurations hold a different number of latched
`values, and in Some configurations of the present invention,
`the size of FIFO buffer 106 is configurable to allow tuning
`of the Sensitivity to Sudden Spikes in the parameter value.
`(For example, a longer buffer is less Sensitive to short Spikes
`in the parameter value.) Some configurations of the present
`invention determine one or more statistical functions (e.g.,
`Standard deviation and average) of the latched values for
`each interval and provide this information to a limit module
`108, which utilizes the one or more determined statistical
`functions to determine one or more alert limits. Module 108
`may also utilize configurable inputs, as described in con
`junction with the various equations disclosed above. In Some
`configurations of the present invention, the Statistical func
`tions and alert limits are redetermined each time a new value
`of the parameter is latched and shifted into buffer 106. Also,
`in Some configurations, the Statistical values are not neces
`Sarily Standard deviation and mean, but may include other
`Suitable Statistical measures, Such as median or mode, or
`another measure of parameter variance.
`0.031) A value of the measured parameter is then com
`pared to the one or more alert limits at module 110. If the
`parameter is outside a bound Set by the one or more alert
`limits, an alarm may be raised by an alert Signal. In Some
`configurations, the alert Signal directly controls one or more
`audible or visual alarm Systems. In Some configurations, an
`alarm is not raised unless a step change persists for a period
`of time, as determined by block 112. The length of time
`required for an alarm indication is configurable in Some
`configurations of the present invention. Also, Some configu
`rations of the present invention also provide a Severity level
`indication based on the persistence of the alarm using a
`severity level module 114.
`0032. In configurations in which parameter measure
`ments are time-Stamped, the time Stamp information can be
`logged when an alarm indication is raised.
`0.033 Some configurations of the present invention
`inhibit an alarm Signal unless a Sufficient number of valid
`samples of the parameter are held in buffer 106. Also, some
`configurations of the present invention utilize a value of a
`parameter latched by latch 104 rather than a current mea
`Surement in the test to determine whether the parameter is
`out of bounds.
`0034 Some configurations of the present invention do
`not include modules 112 and 114, in which case the “alert”
`Signal is used to raise an alarm. Also, Some configurations of
`
`the present invention do not include block 114, in which
`case, the Signal labeled “persistence' is used to raise an
`alarm.
`0035) Software utilized to implement the flow chart of
`FIG. 2 can be used in configurations of the present invention
`represented in FIG. 1. For example, latch 104 and buffer 106
`can be considered in many configurations to comprise
`decision support software 22, and modules 108, 110, 112,
`and 114 may be considered to comprise Step change rule 24.
`It is to be understood that the configuration represented in
`FIG. 2 is only one of many software configurations that can
`be used as decision Support Software 22 and Step change rule
`24.
`0036 FIG. 3 is a graph showing a step change in a
`parameter. Line 200 is indicative of the parameter value in
`FIG. 3. Line 202 is indicative of the upper limit for the
`parameter and line 204 is indicative of the lower limit for the
`parameter. An alarm is raised at a time indicated at 206.
`0037. The parameter or measurand may be any quantity
`of interest. Secondary configurable parameters can be
`applied in Some configurations, including, for example, the
`value of the multiplier for the standard deviation, the value
`of the constant added to the Standard deviation, the size of
`the buffer, and the sample rate of the buffer. A logical on/off
`measurement is the output of the rule, corresponding to the
`Signal that raises the alarm. In Some configurations, a
`quantitative Severity indication may also be provided and
`either recorded or used to modulate or otherwise vary the
`alarm.
`0038 Configurations of the present invention can be used
`to alert machine operators far in advance of developing
`problems. Advantageously, configurations of the present
`invention trigger an alarm when a parameter changes in a
`Statistically significant way rather than after a threshold level
`is crossed.
`0039 Configurations of the present invention can be used
`to provide early warning of problems with machinery in
`power plants, oil refineries, pipeline pumping Stations,
`manufacturing facilities, and any other appropriate applica
`tions. A configurable buffer length in Some configurations of
`the present invention allows tuning of the Sensitivity to
`Sudden Spikes in parameter values. Some configurations of
`the present invention are Suitable for use in providing alarms
`for data collected from nuclear reactor coolant pumpS and
`drive turbines.
`0040. While the invention has been described in terms of
`various specific embodiments, those skilled in the art will
`recognize that the invention can be practiced with modifi
`cation within the Spirit and Scope of the claims.
`
`What is claimed is:
`1. A method for indicating an alarm condition in an
`industrial process, Said method comprising:
`measuring a parameter of the industrial process, Said
`parameter varying over time;
`determining at least one parameter limit, Said at least one
`parameter limit being a function of Said parameter and
`varying over time;
`comparing Said parameter to Said at least one parameter
`limit; and
`
`IPR2023-00626 Page 00007
`
`

`

`US 2005/0246593 A1
`
`Nov. 3, 2005
`
`indicating an alarm condition when Said parameter is
`outside of a bound Set by Said at least one parameter
`limit at a time when Said parameter is compared to Said
`at least one parameter limit.
`2. A method in accordance with claim 1 wherein Said at
`least one parameter limit comprises an upper limit and a
`lower limit.
`3. A method in accordance with claim 2 further compris
`ing buffering Said parameter and using a time-delayed value
`of Said parameter in Said comparing Said parameter to Said
`at least one parameter limit.
`4. A method in accordance with claim 3 wherein Said
`upper limit is an average value of the parameter plus a
`predetermined constant multiple of a Standard deviation of
`the parameter, and Said lower limit is the average value of
`the parameter minus the predetermined constant multiple of
`the Standard deviation of the parameter.
`5. A method in accordance with claim 3 wherein said
`upper limit is an average value of the parameter plus a
`predetermined first constant plus a predetermined Second
`constant multiple of a Standard deviation of the parameter,
`and Said lower limit is the average value of the parameter
`minus the predetermined first constant plus the predeter
`mined Second constant multiple of the Standard deviation of
`the parameter.
`6. A method in accordance with claim 3 wherein said
`upper limit is an average value of the parameter plus a
`predetermined constant and Said lower limit is an average
`value of the parameter minus a predetermined constant.
`7. A method in accordance with claim 3 wherein said
`upper limit and Said lower limit are functions of a median
`value of Said parameter.
`8. A method in accordance with claim 3 wherein said
`upper limit and Said lower limit are functions of a mode of
`Sampled values of Said parameter.
`9. A method in accordance with claim 1 wherein the
`industrial process includes at least one apparatus Selected
`from the group consisting of a gas turbine engine, a Steam
`turbine, an electric generator, an electric motor, a pump, a
`gearbox, and bearings, and Said parameter is Selected from
`the group consisting of pressure, temperature, position,
`acceleration, Velocity, power, current, and fluid flow.
`10. An apparatus for indicating an alarm condition in an
`industrial process, Said apparatus comprising a Sensor con
`figured to measure a parameter of the industrial process, a
`data acquisition System, and a computer, Said apparatus
`configured to:
`measure a parameter of the industrial process, Said param
`eter varying over time;
`determine at least one parameter limit, Said at least one
`parameter limit being a function of Said parameter and
`varying over time;
`compare said parameter to Said at least one parameter
`limit; and
`indicate an alarm condition when said parameter is out
`Side of a bound Set by Said at least one parameter limit
`at a time when said parameter is compared to Said at
`least one parameter limit.
`11. An apparatus in accordance with claim 10 wherein
`Said at least one parameter limit comprises an upper limit
`and a lower limit.
`
`12. An apparatus in accordance with claim 11 further
`configured to buffer Said parameter and using a time-delayed
`value of Said parameter to compare Said parameter to Said at
`least one parameter limit.
`13. An apparatus in accordance with claim 12 wherein
`Said upper limit is an average value of the parameter plus a
`predetermined constant multiple of a Standard deviation of
`the parameter, and Said lower limit is the average value of
`the parameter minus the predetermined constant multiple of
`the Standard deviation of the parameter.
`14. An apparatus in accordance with claim 12 wherein
`Said upper limit is an average value of the parameter plus a
`predetermined first constant plus a predetermined Second
`constant multiple of a Standard deviation of the parameter,
`and Said lower limit is the average value of the parameter
`minus the predetermined first constant plus the predeter
`mined Second constant multiple of the Standard deviation of
`the parameter.
`15. An apparatus in accordance with claim 12 wherein
`Said upper limit is an average value of the parameter plus a
`predetermined constant and Said lower limit is an average
`value of the parameter minus a predetermined constant.
`16. An apparatus in accordance with claim 12 wherein
`Said upper limit and Said lower limit are functions of a
`median value of Said parameter.
`17. An apparatus in accordance with claim 12 wherein
`Said upper limit and Said lower limit are functions of a mode
`of Sampled values of Said parameter.
`18. An apparatus in accordance with claim 10 wherein the
`industrial process includes at least one apparatus Selected
`from the group consisting of a gas turbine engine, a Steam
`turbine, an electric generator, an electric motor, a pump, a
`gearbox, and bearings, and Said parameter is Selected from
`the group consisting of pressure, temperature, position,
`acceleration, Velocity, power, current, and fluid flow.
`19. A medium having machine-readable instructions
`recorded thereon that are configured to instruct a computer
`to:
`input a Sensed parameter of an industrial process, Said
`parameter varying over time;
`determine at least one parameter limit, Said at least one
`parameter limit being a function of Said parameter and
`varying over time;
`compare Said parameter to Said at least one parameter
`limit; and
`indicate an alarm condition when said parameter is out
`Side of a bound Set by Said at least one parameter limit
`at a time when said parameter is compared to Said at
`least one parameter limit.
`20. A medium in accordance with claim 19 wherein said
`at least one parameter limit comprises an upper limit and a
`lower limit.
`21. A medium in accordance with claim 20 further having
`recorded thereon instructions configured to instruct the
`computer to buffer Said parameter use a time-delayed value
`of Said parameter to compare Said parameter to Said at least
`one parameter limit.
`22. A medium in accordance with claim 21 wherein Said
`upper limit is an average value of the parameter plus a
`predetermined constant multiple of a Standard deviation of
`the parameter, and Said lower limit is the average value of
`
`IPR2023-00626 Page 00008
`
`

`

`US 2005/0246593 A1
`
`Nov. 3, 2005
`
`the parameter minus the predetermined constant multiple of
`the Standard deviation of the parameter.
`23. A medium in accordance with claim 21 wherein Said
`upper limit is an average value of the parameter plus a
`predetermined first constant plus a predetermined Second
`constant multiple of a Standard deviation of the parameter,
`and Said lower limit is the average value of the parameter
`minus the predetermined first constant plus the predeter
`mined Second constant multiple of the Standard deviation of
`the parameter.
`24. A medium in accordance with claim 21 wherein Said
`upper limit is an average value of the parameter plus a
`predetermined constant and Said lower limit is an average
`value of the parameter minus a predetermined constant.
`25. A medium in accordance with claim 21 wherein said
`upper limit and Said lower limit are functions of a median
`value of Said parameter.
`26. A medium in accordance with claim 21 wherein Said
`upper limit and Said lower limit are functions of a mode of
`Sampled values of Said parameter.
`27. A medium in accordance with claim 19 wherein the
`industrial process includes at least one apparatus Selected
`from the group consisting of a gas turbine engine, a Steam
`turbine, an electric generator, an electric motor, a pump, a
`gearbox, and bearings, and Said parameter is Selected from
`the group consisting of pressure, temperature, position,
`acceleration, Velocity, power, current, and fluid flow.
`28. A method for indicating an alarm condition in an
`industrial process, said method comprising:
`measuring a parameter of the industrial process, Said
`parameter varying over time;
`latching Said parameter and buffering Said latched param
`eter in a FIFO (first-in, first-out) buffer;
`determining Statistical functions of values of Said buffered
`parameter stored in said FIFO buffer;
`utilizing Said determined Statistical functions to determine
`one or more alert limits,
`comparing value of the parameter to Said one or more alert
`limits, and
`indicating an alarm dependent upon Said parameter being
`outside a bound Set by the one or more alert limits.
`29. A method in accordance with claim 28 wherein said
`comparing the value of the parameter to Said one or more
`alert limits comprises comparing a present value of the
`parameter to the alert limits.
`30. A method in accordance with claim 28 wherein said
`comparing the value of the parameter to Said one or more
`alert limits comprises comparing a latched value of the
`parameter to the alert limits.
`31. A method in accordance with claim 28 wherein said
`indicating an alarm dependent upon Said parameter being
`outside a bound set by the one or more alert limits further
`comprises determine whether the parameter is outside Said
`bound for a Sufficiently long time to indicate an alarm.
`32. A method in accordance with claim 31 further com
`prising indicating a Severity level of the alarm, the Severity
`level being dependent upon the length of time the parameter
`is outside Said bound.
`33. A method in accordance with claim 28 wherein said
`comparing the value of the parameter to Said one or more
`alert limits further comprises inhibiting an alarm if a valid
`
`sample count of parameter values buffered in the FIFO is
`less than a predetermine value.
`34. An apparatus for indicating an alarm condition in an
`industrial process, Said apparatus configured to:
`latch a varying parameter value of the industrial proceSS
`and buffer Successive latched parameter values in a
`FIFO (first-in, first-out) buffer;
`determine statistical functions of values of said buffered
`parameter stored in said FIFO buffer;
`utilize said determined Statistical functions to determine
`one or more alert limits,
`compare value of the parameter to Said one or more alert
`limits, and
`indicate an alarm dependent upon Said parameter being
`Outside a bound Set by the one or more alert limits.
`35. An apparatus in accordance with claim 34 wherein to
`compare the value of the parameter to Said one or more alert
`limits, said apparatus is configured to compare a present
`value of the parameter to the alert limits.
`36. An apparatus in accordance with claim 34 wherein to
`compare the value of the parameter to Said one or more alert
`limits, said apparatus is configured to compare a latched