Transducer fault detection system using slew rate measurements: apparatus and method

• US 20040158435A1
• Filed: 02/12/2003
• Published: 08/12/2004
• Est. Priority Date: 02/12/2003
• Status: Active Grant

• Current Assignee: Bently Nevada Incorporated (General Electric Company)
• Original Assignee: Bently Nevada Incorporated (General Electric Company)
• Inventors: Harker, Roger G., Slates, Richard D., Foster, Ingrid M.
• Granted Patent: US 6,816,816 B2
• Time in Patent Office: Days
• US Class Current: 702/185
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold

Abstract

A transducer fault detection system that transforms transducer measurements into slew rate measurements, and determines which, if any, of the slew rate measurements are anomalous or correlative to faults. The system can generate alarms based on these determinations. The system may also transform transducer measurements into digitized voltage measurements, determine how long a succession of the digitized voltage measurements remain within at least one defined voltage window, and determine if there is a correlation between the determined time duration of digitized voltage measurements and an anomalous condition. Each determined anomalous condition may then be associated to a defined fault for gaining fault specificity.

Claims

1. - A method for detecting faults from a transducer output signal, the steps including:

monitoring a slew rate of a transducer output signal;

comparing the slew rate with a known value; and

correlating the slew rate to a fault when indicated by the comparison step.

2. - The method of claim 1 wherein the monitoring step includes the step of transforming the output signal of the transducer monitoring a moving target of a mechanical system into slew rate measurements.

3. - The method of claim 2 wherein the comparison step includes the step of comparing the slew rate measurements to at least one previously known slew rate value which is greater than that which could be due to the moving target.

4. - The method of claim 3 wherein the correlation step includes the step of correlating those slew rate measurements which are greater than that which could be due to the moving target of the mechanical system to at least one fault in a transducer system monitoring the moving target of the mechanical system.

5. - The method of claim 4 further including the step of alarming off each slew rate measurement which is correlated to said at least one fault for providing mechanical system protection.

6. - The method of claim 4 wherein the mechanical system is a rotating or reciprocating machine.

7. - A transducer fault detection device comprising, in combination:

at least one transducer outputting transducer measurements correlative to movement of a target of a mechanical system being monitored by said transducer;

means, operatively coupled to the transducer, for transforming the transducer measurements into slew rate measurements;

means for determining which, if any, of said slew rate measurements are faster than that which could be due to the moving target being monitored by said transducer; and

means for ascertaining whether or not any of said determined faster slew rate measurements are correlative to transducer faults for providing fault detection.

8. - The transducer fault detection device of claim 7 wherein said means for transforming the transducer measurements into slew rate measurements includes a sampling means for sampling and digitizing the transducer measurements and at least one processor for providing a means for calculating said slew rate measurements from said sampled and digitized transducer measurements for transforming the transducer measurements into said slew rate measurements.

9. - The transducer fault detection device of claim 8 wherein said means for determining which, if any, of said slew rate measurements are faster than that which could be due to the moving target being monitored by said transducer includes means for comparing said slew rate measurements to at least one known slew rate value for determining which, if any, of said slew rate measurements are faster than that which could be due to the moving target being monitored by said transducer.

10. - The transducer fault detection device of claim 9 wherein said means for ascertaining whether or not any of said determined faster slew rate measurements are correlative to transducer faults for providing fault detection includes means for correlating said determined faster slew rate measurements to one or more transducer faults each characterized by having a slew rate which is faster than that which could be due to the moving target of the mechanical system for providing means for censoring transducers for faults such as transducer defects, interconnect defects, interconnect wiring defects, or transducer power supply defects.

11. - A method for detecting transducer faults, the steps including:

transforming transducer measurements made by a transducer monitoring a moving target of a mechanical system into slew rate measurements;

comparing the slew rate measurements to at least one previously known slew rate value which is known to be faster than that which could be due to the moving target of the mechanical system for determining which if any of the slew rate measurements are faster than the at least one previously known slew rate value; and

correlating those slew rate measurements that are determined to be faster than the at least one previously known slew rate value to at least one transducer fault wherein each correlated slew rate measurement is characterized by having a faster slew rate than that which could be due to the moving target of the mechanical system.

12. - The method of claim 11 further including the step of alarming off each slew rate measurement that is correlated to said at least one transducer fault for providing mechanical system protection.

13. - The method of claim 12 wherein the mechanical system is a rotating or reciprocating machine.

14. - A method for detecting faults from a transducer output signal, the steps including:

transforming transducer signals into digitized voltage measurements;

determining a time duration of how long a succession of the digitized voltage measurements remain within at least one defined voltage window;

determining if the succession of the digitized voltage measurements remaining within at least the one defined voltage window for the determined time duration is correlative to an anomalous condition, and associating each determined anomalous condition to at least one defined fault for gaining fault specificity for providing mechanical system protection.

15. - The method of claim 14 further including the step of alarming off each anomalous condition that is associated to at least one defined fault for providing mechanical system protection.

16. - The method of claim 15 wherein the mechanical system is a rotating or reciprocating machine.