SYSTEM AND METHOD FOR OBJECTIVE SELF-DIAGNOSIS OF MEASUREMENT DEVICE CALIBRATION CONDITION

• US 20090312984A1
• Filed: 06/11/2008
• Published: 12/17/2009
• Est. Priority Date: 06/11/2008
• Status: Active Grant

• Current Assignee: Fluke Corporation (Fortive Corp.)
• Original Assignee: Fluke Corporation (Fortive Corp.)
• Inventors: Delajoud, Pierre, Girard, Martin
• Granted Patent: US 8,655,624 B2
• Time in Patent Office: Days
• US Class Current: 702/183
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00

Abstract

A measurement system uses a plurality of transducers that may differ from each other in at least one respect, such as having different operating principles or being made by different manufacturers. Respective measurement values obtained from the transducers are applied to a processor which provides a measured value based on the measurement values from a plurality of the transducers. The processor also provides information about the calibration drift of each of the transducers based upon a comparison between the measurement value obtained from the transducer to a value obtained from a combination of respective measurement values obtained from a plurality of the transducers. The calibration drift information provides an objective evaluation about the calibration condition of each of the transducers. When a transducer is determined to be outside of its calibration tolerance, a calibration needed alert occurs.

Claims

1. A method of measuring a parameter, comprising:

making a plurality of measurements at least some of which are measured independently of the other measurements;

deriving a measured value from at least some of the plurality of measurements; and

using the plurality of measurements to determine whether the accuracy of at least some of the plurality of measurements is less than a predetermined accuracy.

2. The method of claim 1 wherein the act of making a plurality of measurements comprises making a plurality of measurements using a respective plurality of measurement devices having different principles of operation.

3. The method of claim 1 wherein the act of making a plurality of measurements comprises making a plurality measurements using a respective plurality of measurement devices manufactured by different manufacturers.

4. The method of claim 1 wherein the act of deriving a measured value from at least some of the plurality of measurements comprises:

discarding at least one of the measurements based on the value obtained from the at least one measurement compared to a combination of the values obtained from at least some of the other measurements; and

using the remaining measurement to provide the measured value.

5. The method of claim 1 wherein the act of deriving a measured value from at least some of the plurality of measurements comprises averaging the plurality of measurements.

6. The method of claim 1 wherein the act of using the plurality of measurements to determine whether the accuracy of at least some of the plurality of measurements is less than a predetermined accuracy comprises comparing the respective values obtained from each of the plurality of measurements to a value determined from a combination of values obtained from the plurality of measurements.

7. The method of claim 6 wherein the value determined from a combination of the plurality of measurements comprises an average of the respective values obtained from plurality of measurements.

8. The method of claim 1, further comprising providing a calibration alert if the accuracy of at least some of the plurality of measurements is less than the predetermined accuracy.

9. The method of claim 1 wherein the act of making a plurality of measurements comprises making a plurality of fluid pressure measurements.

10. The method of claim 1 wherein the act of making a plurality of measurements comprises making a plurality of electrical measurements.

11. The method of claim 1 wherein the act of making a plurality of measurements comprises making each of the plurality of measurements in the same measurement environment.

12. A measurement system, comprising:

a plurality of measurement devices at least some of which are different from each other, each of the measurement devices providing a respective measurement value; and

a processor coupled to receive the measurement values from the plurality of measurement devices, the processor being operable to derive a measured value from at least some of the plurality of measurement values, the processor further being operable to provide information about calibration drift of at least some of the plurality of calibration devices.

13. The measurement system of claim 12 wherein the plurality of measurement devices have respective principles of operation that differ from each other.

14. The measurement system of claim 12 wherein the plurality of measurement devices comprises measurement devices manufactured by different manufacturers.

15. The measurement system of claim 12 wherein the processor is operable to compare each of the measurement values from the respective measurement devices to a value derived from a combination of the measurement values from a plurality of the respective measurement devices, and, based on the comparison, to select at least one of the measurement values to ignore in determining the measured value.

16. The measurement system of claim 12 wherein the value derived from a combination of the measurement values obtained from a plurality of the respective measurement devices comprises an average of the measurement values obtained from a plurality of the respective measurement devices.

17. The measurement system of claim 12 wherein the processor is operable to provide information about calibration drift of at least some of the plurality of calibration devices by comparing the respective values obtained from each of the plurality of measurement devices to a value derived from a combination of the values obtained from the plurality of the respective measurement devices.

18. The measurement system of claim 17 wherein the value derived from a combination of the values obtained from the plurality of the respective measurement devices comprises an average of the values obtained from the plurality of the respective measurement devices.

19. The measurement system of claim 12 wherein the information about calibration drift of at least some of the plurality of calibration devices provided by the processor comprises a calibration alert.

20. The measurement system of claim 12 wherein each of the measurement devices comprise a respective pressure transducer.

21. The measurement system of claim 12 wherein each of the measurement devices comprise a respective electrical measurement device.

22. The measurement system of claim 12 wherein the plurality of measurement devices are in the same measurement environment.

23. The measurement system of claim 22 wherein the each of the measurement devices comprises a respective pressure transducer, and the measurement system further comprises a housing to which each of the pressure transducers are fluidly coupled in a symmetrical manner, the housing having a pressure port in fluid communication with each of the pressure transducers.

24. The measurement device of claim 23 wherein the pressure port is equidistant from all of the pressure transducers.

25. The measurement device of claim 23 wherein the pressure transducers are positioned so that the gravity effect on the overall measurement device remains regardless of the orientation of the measurement device.