Claims
- 1. A diagnostic device for use in a process control system, comprising:
a sensor signal input, the sensor signal related to a process variable of a process fluid of a process, the process variable sensed by a process variable sensor; a signal preprocessor coupled to the sensor input having a sensor power signal output as a function of a frequency distribution of power in the sensor signal; and a signal evaluator coupled to the sensor power signal output having a condition output related to a condition of the process.
- 2. The diagnostic device of claim 1 wherein the sensor signal has a frequency content of at least about 50 Hz.
- 3. A transmitter including the diagnostic device of claim 1.
- 4. The diagnostic device of claim 1 wherein the process variable sensor comprises a pressure sensor.
- 5. The diagnostic device of claim 1 wherein the process variable sensor comprises electrodes in a magnetic flowmeter.
- 6. The diagnostic device of claim 1 wherein the process variable sensor comprises a sensor in a vortex flowmeter.
- 7. The diagnostic device of claim 1 wherein the process variable sensor comprises a sensor in a coriolis flowmeter.
- 8. The diagnostic device of claim 1 wherein the signal preprocessor isolates a frequency range of the sensor signal.
- 9. The diagnostic device of claim 1 signal preprocessor isolates a frequency range of the sensor signal.
- 10. The diagnostic device of claim 1 wherein the sensor signal has a frequency of between about 0 Hz and about 200 Hz.
- 11. The diagnostic device of claim 1 wherein the function comprises power spectral density.
- 12. The diagnostic device of claim 1 wherein the function is related to a Fourier transform of the sensor signal.
- 13. The diagnostic device of claim 1 wherein the function comprises a wavelet transform of the sensor signal.
- 14. The diagnostic device of claim 1 wherein the signal preprocessor includes a filter.
- 15. The diagnostic device of claim 1 wherein the condition relates to operation of a process control device.
- 16. The diagnostic device of claim 1 wherein the diagnostic device is implemented in a process monitor.
- 17. The diagnostic device of claim 1 wherein the diagnostic device is implemented in a control system.
- 18. The diagnostic device of claim 1 wherein the diagnostic device couples to a communication bus.
- 19. The diagnostic device of claim 18 wherein the communication bus comprises a two-wire loop.
- 20. The diagnostic device of claim 19 wherein the diagnostic device is fully powered with power received from the two-wire loop.
- 21. The diagnostic device of claim 1 wherein the sensor power signal output relates to a vibration noise signal carried in process fluid of the process.
- 22. The diagnostic device of claim 1 wherein the process variable sensor comprises a sensor in an ultrasonic flowmeter.
- 23. The diagnostic device of claim 1 wherein the condition of the process is related to condition of a process device selected from the group of devices consisting of valves, pumps, pump seals, discharge systems, actuators, solenoids, compressors, turbines, agitators, dampers, piping, fixtures and tanks
- 24. The diagnostic device of claim 1 wherein the signal evaluator compares the sensor power signal with a stored value.
- 25. The diagnostic device of claim 1 wherein the signal evaluator comprises a neural network.
- 26. The diagnostic device of claim 1 signal evaluator comprises fuzzy logic.
- 27. A diagnostic method performed in a process control environment, the method comprising:
obtaining a process variable sensor signal; determining a frequency distribution of power in the process variable sensor signal; and evaluating the frequency distribution of power in the process variable sensor signal and providing a condition output related to the process.
- 28. The method of claim 27 wherein determining includes filtering the process variable sensor signal.
- 29. The method of claim 27 wherein determining includes performing a Fourier transformation on the process variable sensor signal.
- 30. The method of claim 29 wherein determining includes performing a wavelet transformation.
- 31. The method of claim 30 wherein performing a wavelet transform comprises performing a discrete wavelet transform.
- 32. The method of claim 27 wherein evaluating comprises comparing frequency distribution of power in the process variable sensor signal to a stored value.
- 33. The method of claim 27 wherein evaluating comprises evaluating the frequency distribution of power in the process variable sensor signal to a neural network.
- 34. The method of claim 27 wherein evaluating comprises applying a rule to the frequency distribution of power in the process variable sensor signal.
- 35. The method of claim 27 wherein the process variable sensor signal comprises a pressure sensor signal.
- 36. The method of claim 27 wherein the process variable sensor signal comprises a sensor output from a coriolis flowmeter.
- 37. The method of claim 27 wherein the process variable sensor signal comprises a sensor output from a vortex flowmeter.
- 38. The method of claim 27 wherein the process variable sensor signal comprises electrode outputs from a magnetic flowmeter.
- 39. The method of claim 27 wherein the process variable sensor signal comprises an output from a sensor in a coriolis flowmeter.
- 40. The method of claim 27 wherein the process variable sensor signal has a bandwidth of at least about 50 Hz.
- 41. The method of claim 27 wherein the condition output relates to a condition of a process control device.
- 42. The method of claim 27 including fully powering the diagnostic device with power from a two-wire loop.
- 43. A process transmitter implementing the method of claim 27.
- 44. A process control system implementing the method of claim 27.
- 45. A process control device implementing the method of claim 27.
- 46. A process monitor implementing the method of claim 27.
- 47. The method of claim 27 wherein the frequency distribution of power in the process variable sensor signal comprises power spectral density.
- 48. A computer-readable medium having stored thereon instructions executable by a microprocessor system in a diagnostic device to diagnose condition of a process, the instructions comprising:
obtaining a process variable sensor signal; determining a frequency distribution of power in the process variable sensor signal; and evaluating the frequency distribution of power in the process variable sensor signal and providing a condition output related to the process.
- 49. A diagnostic device for use in a process control system, comprising:
a sensor signal input, the sensor signal related to a process variable of a process fluid of a process, the process variable sensed by a process variable sensor; signal preprocessing means for determining a frequency distribution of power in the sensor signal; and signal evaluating means for diagnosing a condition of the process based upon the frequency distribution of power in the sensor signal.
Parent Case Info
[0001] The present application is a Continuation-In-Part of and claims priority of U.S. patent application Ser. No. 09/344,631, filed Jun. 25, 1999, the content of which is hereby incorporated by reference in its entirety.
Continuation in Parts (1)
|
Number |
Date |
Country |
Parent |
09344631 |
Jun 1999 |
US |
Child |
10455815 |
Jun 2003 |
US |