Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B9/00—Safety arrangements
  • G05B9/02—Safety arrangements electric
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B23/00—Testing or monitoring of control systems or parts thereof
  • G05B23/02—Electric testing or monitoring
  • G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
  • G05B23/0218—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults
  • G05B23/0224—Process history based detection method, e.g. whereby history implies the availability of large amounts of data
  • G05B23/0227—Qualitative history assessment, whereby the type of data acted upon, e.g. waveforms, images or patterns, is not relevant, e.g. rule based assessment; if-then decisions
  • G05B23/0232—Qualitative history assessment, whereby the type of data acted upon, e.g. waveforms, images or patterns, is not relevant, e.g. rule based assessment; if-then decisions based on qualitative trend analysis, e.g. system evolution
• • G—PHYSICS
  • G06—COMPUTING OR CALCULATING; COUNTING
  • G06N—COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS
  • G06N5/00—Computing arrangements using knowledge-based models
  • G06N5/04—Inference or reasoning models
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/20—Pc systems
  • G05B2219/24—Pc safety
  • G05B2219/24075—Predict control element state changes, event changes

Definitions

• Equipment monitoring systems can collect data from, for example, computational devices
• a computer interface such as a human-machine interface (HMI) may be interconnected with the computational devices to facilitate programming or control thereof, to monitor the computational device, or to provide other such functionality.
• HMI human-machine interface
• CIP common industrial protocol
• computational device detects an error. Further, simply collecting this error data may not permit an operator to engage in playback (i.e. replicate equipment performance) because complete performance data may not be have been transmitted by the computational device.
• Embodiments of a method for monitoring performance of at least one task in controlled equipment are disclosed herein.
• the method includes collecting a series of signals associated with the at least one task. At least some of the signals in the series define timing values for the at least one task.
• the method also includes comparing each of at least some of the timing values to a reference value and generating an accumulated variance value based on the comparisons. Further, the method includes selectively generating a predictive failure indication based on the generated accumulated variance value.
• the method includes collecting a series of signals associated with the at least one task. At least some of the signals in the series define at least a first timing value for the at least one task. The method also includes comparing the first timing value to a reference value. The reference value is based on data other than the series of signals. Further, the method includes generating an indication based on the comparison.
• Embodiments of an apparatus for monitoring data from a computational device configured to control at least one task in equipment are also disclosed herein.
• the apparatus includes a memory a processor configured to execute instructions stored in the memory to collect a series of signals associated with the at least one task. At least some of the signals in the series define timing values for the at least one task.
• the processor is also configured to execute instructions stored in the memory to compare each of at least some of the timing values to a reference value and generate an accumulated variance value based on the comparisons. Further, the processor is configured to execute instructions stored in the memory to selectively generate a predictive failure indication based on the generated accumulated variance value.
• FIG. 1 is schematic diagram of an automation management system according to one embodiment of the present invention
• FIG. 2 is a timing diagram of an exemplary design cycle as used in the automation management system of FIG. 1 ;
• FIGS. 3A-3D are performance diagrams of exemplary actions of the exemplary cycle of FIG. 2;
• FIG. 4 A is a performance data diagram for a cycle as used in the automation management system of FIG. 1 ;
• FIG. 4B is a machine level performance diagram using the cycle performance data of FIG. 4A;
• FIG. 5 A is a performance data diagram for another cycle as used in the automation management system of FIG. 1 ;
• FIG. 5B is a machine level performance diagram using the cycle performance data of FIG. 4A;
• FIG. 6 A is a performance data diagram for another cycle as used in the automation management system of FIG. 1 ;
• FIG. 6B is a machine level performance diagram using the cycle performance data of FIG. 4A.
• FIG. 7 is an exemplary flowchart diagram of a prediction routine used in the automation management system of FIG. 1.
• an automation management system 10 includes a PLC 12 and a PC 14.
• the data that is collected from the PLC 12 can be based on, for example, the programming of the PLC 12, as will be discussed in more detail below.
• PC 14 can include a data access server, such as an OPC (OLE, Object Linking and Embedding, for Process Control) server, to retrieve data from PLC 12 and to convert the hardware communication protocol used by PLC 12 into the server protocol (e.g. OPC protocol).
• OPC OPC
• the data access server is, by way of example, an OPC server other suitable data access servers are available having custom and/or standardized data formats/protocols.
• the data retrieved by the OPC server can optionally be stored in a database (not shown).
• Both PLC 12 and PC 14 can have suitable components such as a processor, memory, input/output modules, and programming instructions loaded thereon as desired or required.
• PLC 12 and PC 14 can be in transmit/receive data through a wired or wireless communication protocol such as RS232, Ethernet, SCADA (Supervisory Control and Data Acquisition). Other suitable communication protocols are available.
• PLC 12 may be in communication with PC 14, or other PCs.
• PLC 12 can be connected to and control any equipment including machines such as clamps or drills. To ease the reader's understanding of the embodiments, the description will refer to machines although the embodiments can be used with equipment other than the machines.
• the machines can be part of any system including but non-limited to machining, packaging, automated assembly or material handling.
• PLC 12 is not limited to being connected to a machine and/or can be connected to any other suitable device.
• Other devices may be used in lieu or in addition to PLC 12 such as PACs (Process Automation Controllers) or DCS (Distributed Control Systems) or any other suitable computational device.
• PACs Process Automation Controllers
• DCS Distributed Control Systems
• the PC 14 can also include a client application to obtain the data from or send commands to PLC 12 through the OPC server.
• the client application can be connected to several OPC servers or two or more OPC servers can be connected to share data.
• PC 14 can include a graphical display representing information such as the status of the machines on the plant floor.
• the HMI can also be located as a separate device from the PC 14.
• PCs Personal Digital Assistants
• PDAs Personal Digital Assistants
• palm top computers palm top computers
• smart phones smart phones
• game consoles any other information processing devices.
• modules e.g. OPC server, client application, etc.
• modules can be distributed across one or more hardware components as desired or required.
• PLC 12 One use of PLC 12 is to take a machine through a repetitive sequence of one or more operations or tasks.
• the completion of the repetitive sequence of tasks can be denoted as a cycle.
• Each task can have, for example, an optimal design start time and design end time in the sequence and resulting duration time ("reference values").
• These optimal design times can be based on, for example, the manufacturer's specification or an equipment user's study of when and how long a certain tasks should be executed.
• the design times can be determined by any other method.
• an exemplary design cycle 30 is illustrated from time tl- t20.
• the design cycle includes nine tasks 32a-i (collectively referred to as tasks 32).
• each task 32 is designed to begin operation at a specific start time and designed to end operation at a specific end time.
• PLC 12 can be programmed to collect this start time and end time information and made available to PC 14.
• start time and end time information can be sent to PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or PC 14 can periodically poll PLC 12. Accordingly, rather than collecting unnecessary information from PC 14 or
• PLC 12 can collect and transmit information that can be used to appropriately monitor and determine a reactive, preventive and/or predictive plan for the machine(s) being controlled. This information can be sent at the end of the cycle 30, during the cycle 30 upon request by the PC 14 or at any other time as desired or required.
• advance pin 1 task 32a starts at tO and ends at tl and has a duration of tl-tO
• advance pin 2 task 32b starts at tO and ends at tl and has a duration of tl-tO
• close clamp 1 task 32c starts at tl and ends at t2 and has a duration of t2-tl
• close clamp 2 task 32d starts at tl and ends at t2 and has a duration of t2-tl
• weld task 32e starts at t2 and ends at tl8 and has a duration of tl8-t2
• open clamp 1 task 32f starts at tl8 and ends at tl9 and has a duration of tl9-tl8
• open clamp 2 task 32g starts at tl8 and ends at tl9 and has a duration of tl9-tl8
• return pin 1 task 32h starts at tl9 and ends at t20 and has a duration of t20-t
• PLC 12 generally receives input data, output data and/or other data ("series of signals") from the machines they control.
• Each task 32 can be defined as a series of one or more input and/or output states.
• the tasks 32 can be defined, for example, by a programmer during software development for the PLC 12.
• PLC 12 can determine whether advance pin 1 task 32a has been complete by examining whether certain inputs and/or outputs or any other condition (e.g. timer) are set to their correct states or values.
• states does not limit embodiments of the invention to digital input and/or signals.
• analog inputs or outputs, or a combination of digital and analog inputs or outputs can be collected from the machines and can be used to define each task 32.
• FIGS. 3A-3D exemplary performance graphs 50, 60, 70 and 80 of task 32a, task 32b, task 32c and tasks 32d are shown, respectively, over one hundred cycles.
• advance pin 1 task 32a is designed to complete its operation within, for example, one second, as indicated by base line 52.
• the actual operation advance pin 1 task 32a is indicated by a series of plot points 54.
• Each plot point 54 can represent the actual completion time or duration ("timing value") for task 32a during that particular cycle.
• the completion time of task 32a is gradually increasing. This can, for example, provide notice to a user that an input and/or an output associated with task 32a is or may in the future experiencing a failure.
• timing value illustrated in FIGS. 3A-3D other timing values are available in lieu of or in addition to duration.
• other timing values include a start time or end time for the task.
• advance pin 2 task 32b is designed to complete its operation within one second, as indicated by base line 62 and the actual operation of task 32b is indicated by a series of plot points 64.
• Close clamp 1 task 32c is designed to complete its operation within one second, as indicated by base line 72 and the actual operation of task 32c is indicated by a series of plot points 74.
• Close clamp 2 task 32d is designed to complete its operation within one second, as indicated by base line 82 and the actual operation of task 32d is indicated by a series of plot points 84. Since the series of plots points 64, 74 and 84 do not, for example, consistently deviate from the base lines 62, 72 and 82, the user(s) can, for example, ascertain that the tasks are 32b-d are operating normally.
• performance graphs 50, 60, 70 and 80 are merely exemplary. Other performance graphs may contain other data, depicted using another graph type, or combined into one graph. Further, although 100 cycles are shown, performance graphs can contain any number of cycles.
• FIGS. 4A, 5A and 6A are performance data diagrams 100, 120 and 140, respectively.
• the performance data diagram 100 includes information for a first cycle 102
• the performance data diagram 120 includes information for a twentieth cycle 122
• performance data diagram 140 includes information for a hundredth cycle 142. It is to be understood that these cycles are selected from the 100 cycles previously shown but are in no way intended to limit the scope of the embodiments disclosed herein. Rather, selection of these cycles is intended to assist the reader's understanding of embodiments. Other cycles can contain different data.
• the cycles 102, 122 and 142 can include tasks 32.
• performance data can include design cycle data 104, learned cycle data 106, current cycle data 108 ("timing value"), current versus design cycle data 110, current versus learned cycle data 112, accumulated current versus design cycle data 114 and accumulated current versus learned cycle data 114.
• Design cycle data 104 can include data pertaining to design times for the certain machine performing the tasks and is not based on the series of signals collected from the particular machine being monitored.
• each task may have an expected start time, end time and duration based on for example, a manufacturer' s specification or as set by a user. For example, if a manufacturer' s specification indicates that the weld task 32e should be performed in 16 seconds, the design cycle time can be 16 seconds.
• Design cycle times 104 can be determined by other methods. The design cycle times 104 are preferably the same throughout the execution of the tasks 32, although in some embodiments the design cycle can change.
• Learned cycle time 106 can include data pertaining to a reference time for a certain machine.
• learned cycle time 106 is a reference value based on the series of signals collected from the machine.
• a user can cause the machine to execute a cycle of tasks 32a-i, in order to teach the system the reference data for that particular machine.
• These learned cycle times can be recorded, for example, during setup of the machine, maintenance of the machine or at any other suitable time.
• the machine can begin operation and can begin collecting current cycle times for each task 32.
• Current cycle time 108 can be the duration of the time needed to complete each task (i.e. difference between start time and end time).
• the welding process lasted 16.073 seconds.
• the welding process lasted 15.987 seconds.
• the welding process lasted 15.937 seconds.
• the start time and end time and/or the duration for each task 32 can be collected and sent to the PC 14.
• the current versus design time can be calculated for each task 32.
• Current versus design time 110 can be the difference between the design cycle times 104 and the current cycle times 108.
• current versus learned time 112 can be the difference between the learned cycle times 106 and the current cycle times 108.
• the current versus design time 110 and current versus learned time 112 calculations can be made by PC 14 or by any other module. For example, if the HMI is a separate module than the PC 14, the HMI can perform the calculations.
• a threshold value can indicate that the task is operating normally and a normal operation indicator can be generated (e.g. at PC 14) as will be discussed in more detail below.
• a normal operation indicator can be generated (e.g. at PC 14) as will be discussed in more detail below.
• the current versus design time 110 is between 10% and 25% of the design cycle time 104, then the current cycle has been executed within a cautionary threshold.
• the cautionary threshold can indicate that an action may be needed on some input or output associated with that certain task.
• a cautionary indicator can be generated that indicates that the current cycle is within the cautionary threshold. If the current versus design time 110 is greater than 25% of the design cycle time 104, then the current cycle has been executed within a warning threshold.
• the warning threshold can indicate that an action may be needed on some input or output associated with that certain task and a warning indicator can be generated as will be discussed in more detail below.
• any number of threshold ranges can be used with different range values.
• the current versus learned time 112 instead of the current versus design time 110 can be used to determine whether the task 32 is operating within a predetermined threshold. Other embodiments may contain different calculations to ascertain whether the execution time of the tasks is acceptable. For example, rather than using the design cycle time 104, the learned cycle time can be used to ascertain whether the task has been executed within an acceptable threshold.
• this information can be displayed to the user(s). For example, if the tasks 32 have been executed in the acceptable threshold, that particular task can be highlighted, for example, in green ("normal operation indicator”). Similarly, for example, if the tasks 32 have been executed within the cautionary threshold, that particular task can be highlighted in yellow (“cautionary indicator”) and if the tasks 32 have been executed within the warning threshold, that particular task can be highlighted in red (“warning indicator”). In other embodiment, the indicators are audible rather than visually displayed to the user. Other techniques for generating indicators are also available.
• tasks 32a-i have been executed in the acceptable threshold.
• tasks 32a-h have been executed in the acceptable threshold and task 32i has been executed within the cautionary threshold.
• tasks 32b-h have been executed within the acceptable threshold and tasks 32a and 32i have been executed within the warning threshold.
• the accumulated current versus design time 114 (“accumulated variance value”) can be calculated for each task 32.
• the accumulated current versus design time 114 can be the running total or the sum of the current versus design time 110 across some or all cycles (e.g. 100 cycles) for a particular machine run. The machine run may be terminated based on, for example, user(s) intervention, machine breakdown etc.
• the accumulated current versus learned time 116 (“accumulated variance value") can be calculated for each task 32.
• the accumulated current versus design time 116 can be the running total or sum of the current versus learned time 116 across all cycles (e.g. 100 cycles) for a particular machine run.
• the accumulated current versus learned time 114 and the accumulated current versus design time 116 can be calculated at PC 14, or on any other computational device (e.g. PLC 12).
• Both the accumulated current versus design times 114 and the accumulated current versus learned times 116 can be graphed on a machine level performance diagram for each cycle and for each task 32 as shown in FIGS. 4B, 5B and 6B.
• Seriesl 214 represents the accumulated current versus design time 114 for each task 32
• Series2 216 represents the accumulated current versus learned time 116 for each task.
• the machine level performance can be displayed, for example, a HMI.
• the accumulated current versus design time 114 and/or the accumulated current versus learned time 116 increase, it can alert the user(s) that the particular task may be experiencing a problem that may require an action. For example, as can be seen from FIG.
• task 32a has an accumulated current versus design time 114 of 24.356 seconds and an accumulated current versus learned time of 24.656 seconds, which may indicate that advance pin2 task 32a is experiencing a problem.
• a similar observation can be made in regard to return pin2 task 32i.
• FIG. 7 is a prediction routine 300 that can be used in automation management system 10.
• a user enters one or more threshold values for at least one task.
• a user enters one or more reference values (e.g. design cycle time 104) at block 304.
• Control then moves to block 306 to collect data or a series of signals from, for example, a machine being controlled PLC 12.
• PLC 12 can, in turn, send timing values to PC 14 related to the performance of one or more tasks (e.g. tasks 32a-i).
• the series of signals can be collected directly from the machine being controlled.
• control moves to determine the variances or differences (e.g. current versus design time 110) between the reference value and one or more of the timing values collected from PLC 12 over a period of time.
• Design cycle data and/or learned cycle data can be used to determine the differences.
• the period of time may be any suitable value. As one example, the period of time is 2 seconds.
• control moves to sum the variance to generate an accumulated variance value (e.g. accumulated current versus design time 114).
• control moves to block 312 to perform trend pattern detection to predict a potential failure of the machine.
• trend pattern detection determines a slope of the accumulated variance value.
• Control then moves to decision block 314 to determine if a pattern has been detected.
• a pattern can be detected if the slope of the accumulated variance value is either generally increasing or generally decreasing over the period of time rather than being generally constant. When the slope is generally constant, the accumulated variance value does not deviate significantly from zero.
• the value of the differences are at or close to zero.
• FIG. 3A One example of a detected pattern, is shown in FIG. 3A where the slope of the accumulated variance value is illustrated as generally increasing.
• FIGS. 3B-D show the slopes of their respective accumulated variance values as generally constant.
• Other suitable techniques of pattern detection are also available that do not include calculation of slope for the accumulated variance value
• control can move to step 316 to report the prediction of the potential failure.
• the prediction can be reported by generating the predictive failure indicator. Otherwise, if no pattern is detected (i.e. the slope is generally constant) the predictive failure indicator is not generated.
• the predictive failure indicator can be audible or visually displayed to the user at PC 14. Other suitable techniques for generating the predictive failure are also available.
• the information collected from PLC 12 can be used in all aspects of reactive, predictive and preventive maintenance.
• the operation of the tasks 32 can be monitored using any other statistical process control method or any other suitable method.
• the information related to the executed tasks can be displayed in any other manner using control charts or any other suitable graphical display such as a Gantt chart.
• embodiments of the present invention are not limited to use in industrial factories, packaging plants etc.
• embodiments of the present invention can be suitably incorporated into a monitoring and maintenance system of a rollercoaster or any other system that contains a computational device.

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• 2010
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