Sensor systems and methods of operation

• US 20060125492A1
• Filed: 12/14/2004
• Published: 06/15/2006
• Est. Priority Date: 12/14/2004
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Ruud, James Anthony, Dasgupta, Samhita, Balasubramaniam, Mahadevan, Andarawis, Emad Andarawis, Rickards, Charles
• Granted Patent: US 7,180,305 B2
• Time in Patent Office: Days
• US Class Current: 324/667
• CPC Class Codes: G01D 5/24 by varying capacitance

Abstract

A technique for operating a sensor system is provided. The method includes exciting a first sensor with a first excitation signal at a first frequency and exciting a second sensor with a second excitation signal at a second frequency. The technique also includes combining a first measurement signal generated from the first sensor with a second measurement signal generated from the second sensor to determine a sensed parameter. The technique may be employed for reducing crosstalk between closely proximate sensors, such as capacitive probes, and may serve to determine distances within operating machines, such as turbine systems.

Claims

1. A method of operating a sensor system comprising:

exciting a first sensor with a first excitation signal at a first frequency;

exciting a second sensor with a second excitation signal at a second frequency different from the first frequency; and

combining a first measurement signal generated from the first sensor with a second measurement signal generated from the second sensor to determine a sensed parameter.

2. The method of claim 1, wherein the first and second sensors are capacitive probes, and wherein the sensed parameter is a capacitance.

3. The method of claim 1, wherein the first and second sensors are disposed in a close proximity to one another.

4. The method of claim 1, wherein the first and second frequencies are harmonically unrelated.

5. The method of claim 1, wherein the first and second sensors are excited simultaneously.

6. The method of claim 1, further comprising:

detecting a first signal from the first sensor using a synchronous measurement scheme based on the first frequency to generate the first measurement signal; and

detecting a second signal from the second sensor using the synchronous measurement scheme based on the second frequency to generate the second measurement signal.

7. The method of claim 6, wherein the first and second signals comprise reflected signals.

8. The method of claim 7, wherein the synchronous measurement scheme comprises performing a plurality of phase measurements to determine a phase between each of the reflected signals and the respective excitation signals.

9. The method of claim 8, wherein the phase measurements comprise filtering each of the phases to obtain the first and second measurement signals.

10. The method of claim 9, wherein filtering comprises averaging the phases.

11. The method of claim 1, further comprising exciting at least one additional sensor with an excitation signal at a respective frequency that is different from the first and second frequencies, wherein the combining comprises combining each of the respective measurement signals to determine the sensed parameter.

12. A method of measuring a clearance between a first object and a second object, said method comprising:

exciting a first capacitive sensor with a first excitation signal at a first frequency to generate a first measurement signal;

exciting a second capacitive sensor with a second excitation signal at a second frequency different from the first frequency to generate a second measurement signal; and

combining the first measurement signal with the second measurement signal to determine a capacitance, wherein the capacitance is representative of the clearance between the first and second objects.

13. The method of claim 12, further comprising detecting corresponding first and second reflected signals from the first and second sensors via a synchronous measurement scheme to generate the first and second measurement signals.

14. The method of claim 13, wherein the synchronous measurement scheme comprises performing a plurality of phase measurements to determine a phase between each of the reflected signals and the respective excitation signals, and wherein the first and second frequencies are harmonically unrelated.

15. The method of claim 14, wherein the phase measurements comprise filtering each of the phases to obtain the first and second measurement signals.

16-18. -18. (canceled)

19. A method of operating a sensor system comprising:

exciting a first sensor with a first excitation signal;

switching between the first sensor and a second sensor;

exciting the second sensor with a second excitation signal; and

combining a first measurement signal from the first sensor with a second measurement signal from the second sensor to determine a sensed parameter.

20-40. -40. (canceled)

41. A sensor system comprising;

at least two sensors configured to receive respective excitation signals, each of the excitation signal having a respective frequency;

at least one switch coupled to the sensors and configured to switch the excitation signals between the sensors at a pre-determined switching interval; and

a combiner configured to combine a plurality of measurement signals from the sensors to determine a sensed parameter.

42. The sensor system of claim 41, wherein the sensors are capacitive probes, and wherein the sensed parameter is capacitance.

43. The sensor system of claim 41, further comprising at least one signal generator configured to supply the excitation signals to the sensors.

44-46. -46. (canceled)

47. A sensor system comprising:

a first set of sensors comprising at least two sensors configured to receive a respective excitation signal, each of the excitation signals having a respective frequency;

a second set of sensor comprising at least two sensors configured to receive a respective excitation signal, each of the excitation signals having a respective frequency;

at least one switch configured to switch the excitation signals from the first set of sensors to the second set of sensors; and

a combiner configured to combine a plurality of measurement signals from the first and second sets of sensors to determine a sensed parameter.

48-50. -50. (canceled)