Preventative maintenance and diagonstic system

• US 5,754,451 A
• Filed: 02/29/1996
• Issued: 05/19/1998
• Est. Priority Date: 02/29/1996
• Status: Expired due to Term

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Williams, Chet R.
• Primary Examiner(s): Zanelli, Michael
• Assistant Examiner(s): Pipala, Edward J.
• Application Number:
  US08/608,866
• Time in Patent Office: 810 Days
• Field of Search: 364/141, 364/146, 364/184, 364/185, 364/188, 364/468.15, 364/468.16, 364/468.17, 364/468.18, 364/479.19, 364/479.22, 364/550, 364/580, 364/551.01, 395/183.01, 395/183.13, 395/184.01
• US Class Current: 702/185
• CPC Class Codes: G05B 19/4184 characterised by fault tolerance, reliability of production system
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

A maintenance system for a machine (12) controlled by a programmable logic controller (14) having a memory (20) which stores input data received from the machine (12) and output data communicated to the machine (12). The maintenance system includes a computer (33) interfaced to the memory to be non-intrusive with respect to the programmable logic controller (14). The computer (33) is operative to monitor a state of the machine (12) over a plurality of manufacturing cycles, the state including at least a portion of the input data and the output data. The computer (33) is further operative to detect a fault condition for a component of the machine (12) based upon a state of a current manufacturing cycle and a state of a previous manufacturing cycle. A display device (32) is in communication with the computer (33) to alert an operator of the fault condition and to graphically display a location of the component within the machine (12) to facilitate a corrective measure by the operator.

Claims

1. A maintenance system for a machine controlled by a programmable logic controller, the programmable logic controller including a memory which stores input data received from the machine and output data communicated to the machine, the maintenance system comprising:

a computer interfaced to the memory and prohibited from modifying the memory, the computer operative to monitor a state of the machine over a plurality of manufacturing cycles, the state including at least a portion of the input data and the output data, the computer further operative to detect a fault condition for a component of the machine based upon a comparison of a current state for the manufacturing cycle and a previous state for the manufacturing cycle; and

a display device in communication with the computer to alert an operator of the fault condition and to graphically display a location of the component within the machine to facilitate a corrective measure by the operator.

2. The maintenance system of claim 1 wherein the display device displays an image of the machine including an image of the component therein, wherein the image of the component is highlighted in a predetermined manner to indicate the fault condition.

3. The maintenance system of claim 2 wherein upon an operator-initiated action to select the image of the component, the display device displays information on correcting the fault condition.

4. The maintenance system of claim 3 wherein upon the operator-initiated action, a magnified image of the component is displayed to graphically illustrate the corrective measure.

5. The maintenance system of claim 1 wherein the computer is operative to maintain a respective cycle count for each of at least one component of the machine, each cycle count indicative of a number of manufacturing cycles performed by a corresponding component, and wherein the display device alerts the operator when a cycle count has reached a predetermined limit and graphically displays a location of the component corresponding to the cycle count within the machine to facilitate a corrective measure by the operator.

6. The maintenance system of claim 5 wherein the predetermined limit is indicative of a mean time between failures for the component.

7. The maintenance system of claim 5 wherein the display device displays an image of the machine including an image of the component whose cycle count reached the predetermined limit, wherein the image of the component is highlighted in a predetermined manner.

8. The maintenance system of claim 1 wherein the computer is operative to maintain a respective preventative maintenance schedule for each of at least one component of the machine, and wherein the display device alerts the operator when a component is due for preventative maintenance, the display device graphically displaying a location of the component within the machine to facilitate a preventative maintenance measure by the operator.

9. The maintenance system of claim 8 wherein the display device displays an image of the machine including an image of the component due for preventative maintenance, wherein the image of the component is highlighted in a predetermined manner.

10. The maintenance system of claim 1 wherein the computer forms a transition history for a moving component over each of a plurality of manufacturing cycles, and wherein the display device alerts the operator when a transition history of a current manufacturing cycle differs from a transition history of a previous manufacturing cycle beyond a predetermined level, the display device graphically displaying a location of the moving component within the machine.

11. The maintenance system of claim 10 wherein the display device displays an image of the machine including an image of the moving component, wherein the image of the moving component is highlighted in a predetermined manner.

12. The maintenance system of claim 1 wherein the computer maintains a library of states of the machine for fault conditions, and wherein the display device displays potential failure points based upon the library upon detecting a fault condition.

13. A computer-implemented method of maintaining a machine controlled by a programmable logic controller, the programmable logic controller including a memory which stores input data received from the machine and output data communicated to the machine, the method comprising the steps of:

monitoring the memory while prohibiting modification thereof to monitor a state of the machine over a plurality of manufacturing cycles, the state including at least a portion of the input data and the output data from the memory;

comaring a current state for the manufacturing cycle to a previous state for the manufacturing cycle;

detecting a fault condition for a component of the machine based upon a difference between the current state and the previous state of the manufacturing cycle;

alerting an operator of the fault condition; and

graphically displaying a location of the component within the machine to facilitate a corrective measure by the operator.

14. The computer-implemented method of claim 13 wherein the step of graphically displaying includes displaying an image of the machine and an image of the component therein, wherein the image of the component is highlighted in a predetermined manner to indicate the fault condition.

15. The computer-implemented method of claim 14 further comprising the steps of:

receiving an operator-initiated action to select the image of the component; and

displaying information on correcting the fault condition upon receiving the operator-initiated action.

16. The computer-implemented method of claim 15 further comprising the step of displaying a magnified image of the component to graphically illustrate the corrective measure upon receiving the operator-initiated action.

17. The computer-implemented method of claim 13 further comprising the steps of:

maintaining a respective cycle count for each of at least one component of the machine, each cycle count indicative of a number of manufacturing cycles performed by a corresponding component;

alerting the operator when a cycle count has reached a predetermined limit; and

graphically displaying a location of the component corresponding to the cycle count within the machine to facilitate a corrective measure by the operator.

18. The computer-implemented method of claim 17 wherein the predetermined limit is indicative of a mean time between failures for the component.

19. The computer-implemented method of claim 17 wherein the step of displaying the location of the component corresponding to the cycle count includes displaying an image of the machine with an image of the component whose cycle count reached the predetermined limit, wherein the image of the component is highlighted in a predetermined manner.

20. The computer-implemented method of claim 13 further comprising the steps of:

maintaining a respective preventative maintenance schedule for each of at least one component of the machine;

alerting the operator when a component is due for preventative maintenance; and

graphically displaying a location of the component due for preventative maintenance within the machine to facilitate a preventative maintenance measure by the operator.

21. The computer-implemented method of claim 20 wherein the step of graphically displaying the location of the component due for preventative maintenance includes displaying an image of the machine including an image of the component due for preventative maintenance, wherein the image of the component is highlighted in a predetermined manner.

22. The computer-implemented method of claim 13 further comprising the steps of:

forming a transition history for a moving component over each of a plurality of manufacturing cycles;

alerting the operator when a transition history of a current manufacturing cycle differs from a transition history of a previous manufacturing cycle beyond a predetermined level; and

graphically displaying a location of the moving component within the machine.

23. The computer-implemented method of claim 22 wherein the step of graphically displaying the location of the moving component includes displaying an image of the machine and an image of the moving component therein, wherein the image of the moving component is highlighted in a predetermined manner.

24. The computer-implemented method of claim 13 further comprising the steps of:

maintaining a library of states of the machine for fault conditions; and

displaying potential failure points based upon the library upon detecting a fault condition.