Process for auto calibration of a microprocessor based overcurrent protective device and apparatus

• US 5,325,315 A
• Filed: 06/08/1993
• Issued: 06/28/1994
• Est. Priority Date: 12/28/1990
• Status: Expired due to Term

• Current Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Engel, Joseph C., Prather, Edward C., Saletta, Gary F., Winter, Marlan L.
• Primary Examiner(s): Harvey, Jack B.
• Assistant Examiner(s): Choi, Jae H.
• Application Number:
  US08/073,636
• Time in Patent Office: 385 Days
• Field of Search: 364/571.01, 364/571.02, 364/571.04, 364/571.05, 364/571.06, 364/571.07, 364/571.08, 364/483, 364/424.03
• US Class Current: 702/105
• CPC Class Codes: H01H 47/325 by switching regulator

Abstract

Process and apparatus for calibrating an electrical device such as a circuit breaker, motor controller or monitor is taught. A precision power supply device is interconnected by way of appropriate input channels to the device to be calibrated for supplying a precise accurate calibration variable as an input. A personal computer PC is interlinked by way of a communications network with the apparatus to be calibrated and is also interlinked with the precision supply device so that the personal computer PC has available the exact value of input variable utilized. Gain adjustment calibration is made by supplying the predetermined value of circuit variables, for instance 10 amperes or 120V to the input terminals of the device being calibrated. Upon command, the personal computer PC instructs the device being calibrated to deliver to the personal computer PC those values of input variable which the device being calibrated interprets as the input variable value. The personal computer PC compares this value with the actual value and generates a correction factor which the personal computer PC sends back to the device being calibrated for storage in an EEPROM. Consequently, during subsequent use after the calibration procedure has been completed and the calibration features have been safely "locked" away in the EEPROM, all readings will be adjusted by the aforementioned calibration factor to compensate for errors which may exist in other portions of the device being calibrated.

Claims

1. A process for calculating a digital calibration factor for an electrical device of the type that acts in the presence of a predetermined value of an input electrical variable at an input of said electrical device to perform a function, where said calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device, comprising the steps of:

supplying a first value of said input electrical variable to said input;

sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

communicating said first derived value to an external computing means which also has said first value of input electrical variable available thereto;

calculating a calibration factor within said external computing means according to the relationship;

said calibration factor is related to said first value of input electrical variable and said first derived value; and

communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said electrical device in performing said function.

2. The process as claimed in claim 1 wherein said input electrical variable is electrical current.

3. The process as claimed in claim 1 wherein said input electrical variable is electrical voltage.

4. The process as claimed in claim 1 wherein said input electrical input variable is frequency.

5. The process as claimed in claim 1 wherein said input electrical variable is electrical power.

6. The process as claimed in claim 1 wherein said corresponding derived electrical value multiplied by said calibration factor equals said predetermined value.

7. The process as claimed in claim 1 wherein said calibration factor algebraically added to said corresponding derived electrical value equals said predetermined value.

8. The process as claimed in claim 1 wherein said external computing means is a digital computer.

9. The process as claimed in claim 8 wherein said digital computer is a personal computer.

10. The process as claimed in claim 1 wherein said calibration factor is a gain factor.

11. The process as claimed in claim 1 wherein said input electrical variable is an analog value.

12. The process as claimed in claim 1 wherein said calibration factor memory region is part of a microprocessor.

13. The process as claimed in claim 1 wherein said calibration factor memory region is an EEPROM.

14. The process as claimed in claim 1 wherein said electrical device is a motor control device.

15. The process as claimed in claim 1 wherein said electrical device is a circuit breaker.

16. The process as claimed in claim 1 wherein said electrical device is a monitor.

17. The process as claimed in claim 1 wherein said function is performed using said corresponding derived value to which said calibration factor is applied to produce said predetermined value of said input electrical value.

18. In combination, an electrical device of the type that acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a function, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical variable to said input, said electrical device sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

external computing means having said first value of said input electrical variable available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calibrating a calibration factor according to the relationship;

said calibration factor equals said first value of said input electrical variable divided by said first derived value; and

second communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said electrical device in performing said function.

19. The combination as claimed in claim 18 wherein said input electrical variable is electrical current.

20. The combination as claimed in claim 18 wherein said input electrical variable is electrical voltage.

21. The combination as claimed in claim 18 wherein said input electrical variable is frequency.

22. The combination as claimed in claim 18 wherein said input electrical variable is electrical power.

23. The combination as claimed in claim 18 wherein said corresponding derived electrical value multiplied by said calibration factor equals said predetermined value.

24. The combination as claimed in claim 18 wherein said calibration factor algebraically added to said corresponding derived value equals said predetermined value.

25. The combination as claimed in claim 18 wherein said external computing means is a digital computer.

26. The combination as claimed in claim 25 wherein said digital computer is a personal computer.

27. The combination as claimed in claim 18 wherein said calibration factor is a gain factor.

28. The combination as claimed in claim 18 wherein said input electrical variable is an analog value.

29. The combination as claimed in claim 18 wherein said calibration factor memory region is part of a microprocessor.

30. The combination as claimed in claim 18 wherein said calibration factor memory region is an EEPROM.

31. The combination as claimed in claim 18 wherein said electrical device is a motor control device.

32. The combination as claimed in claim 18 wherein said electrical device is a circuit breaker.

33. The combination as claimed in claim 18 wherein said electrical device is a monitor.

34. The combination as claimed in claim 18 wherein said electrical device includes means performing said function using said corresponding derived value to which said calibration factor is applied as said predetermined value.

35. In combination, an electrical device of the type that acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a function, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical variable to said input, said electrical device sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

external computing means having said first value of input electrical variable available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calculating a calibration factor according to the relationship;

said calibration factor is related to said first value of input electrical variable and said first derived value; and

second communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said electrical device in performing said function.

36. In combination, a monitor of the type that acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a function, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical variable to said input, said monitor sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

external computing means having said first value of input electrical variable available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calculating a calibration factor according to the relationship;

said calibration factor is related to said first value of input electrical variable and said first derived value; and

second communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said monitor in performing said function.

37. In combination, a circuit breaker of the type that acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a function, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical variable to said input;

said circuit breaker sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

external computing means having said first value of input electrical variable available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calculating a calibration factor according to the relationship;

said calibration factor is related to said first value of input electrical variable and said first derived value; and

second communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said circuit breaker in performing said function.

38. In combination, a motor controller of the type that acts in the presence of a predetermined value of an input electrical variable at an input thereof to perform a function, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical variable to said input, said motor controller sensing said supplied input electrical variable and producing a corresponding first derived value related thereto;

external computing means having said first value of input electrical variable available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calculating a calibration factor according to the relationship;

said calibration factor is related to said first value of input electrical variable and said first derived value; and

said communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said motor controller in performing said function.

39. A process for calculating a digital calibration factor for an electrical device of the type that acts in the presence of a predetermined value of an input electrical signal at an input of said electrical device which electrical signal is related to a variable to perform a function related to said variable, where said calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device, comprising the steps of:

supplying a first value of said input electrical signal to said input;

sensing said supplied input electrical signal and producing a corresponding first derived value related thereto;

communicating said first derived value to an external computing means which also has said first value of input electrical signal available thereto;

calculating a calibration factor within said external computing means according to the relationship;

said calibration factor is related to said first value of input electrical signal and said first derived value; and

communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said electrical device in performing said function.

40. In combination, an electrical device of the type that acts in the presence of a predetermined value of an input electrical signal at an input thereof which electrical signal is related to a variable to perform a function related to said variable, where a calibration factor is digitally stored in a calibration factor memory region of said electrical device and where any input electrical value within a range of input electrical values provides a corresponding derived electrical value in said device;

supply means for supplying a first value of said input electrical signal to said input;

said electrical device sensing said supplied input electrical signal and producing a corresponding first derived value related thereto;

external computing means having said first value of input electrical signal available thereto;

first communication means for communicating said first derived value to said external computing means, said external computing means calculating a calibration factor according to the relationship;

said calibration factor equals said first value of input electrical signal divided by said first derived value; and

second communication means for communicating said calibration factor to said calibration factor memory region for digital placement therein and subsequent use by said electrical device in performing said function.