Method and apparatus for suppression of spikes detected by a proximity sensor

1. A method for suppressing a non-periodic random event in a proximity system, the method comprising:

receiving an output signal generated by a proximity sensor in the proximity system and monitoring at least a magnitude of the output signal;

determining whether a spike having a magnitude exceeding a prescribed threshold value has occurred in the received output signal;

when a spike in the received output signal is detected, setting an output of the proximity system to a prescribed level for a prescribed duration of time;

when the prescribed duration of time has elapsed, determining whether the output signal generated by the proximity sensor meets one or more prescribed criteria indicative of a shutdown condition;

when it is determined that the output signal generated by the proximity sensor meets said prescribed criteria indicative of a shutdown condition, setting the output of the proximity system to a level exceeding an alarm threshold of the proximity system; and

when it is determined that the output signal generated by the proximity sensor fails to meet at least one of said prescribed criteria, thereby indicating that the spike in the output signal generated by the proximity sensor was caused by a non-vibration induced random event, releasing suppression of the output of the proximity system.

2. The method of claim 1 , wherein determining whether the output signal meets said one or more prescribed criteria indicative of a shutdown condition comprises determining whether a magnitude of the spike in the received output signal exceeds a prescribed threshold value, and determining whether a duration of the spike exceeds a prescribed time.

3. The method of claim 1 , wherein releasing suppression of the output of the proximity system comprises setting the output of the proximity system equal to an actual output level based on the output signal generated by the proximity sensor.

4. The method of claim 1 , wherein at least one of the prescribed threshold value and the prescribed duration of time are user programmable.

5. The method of claim 1 , wherein the at least one of the prescribed threshold value and the prescribed duration of time are set by a user via a graphical user interface presented to the user.

6. The method of claim 1 , wherein the output signal generated by the proximity sensor is an analog proximity signal, and wherein the method further comprising:

converting the analog proximity signal into a digital signal representing the analog proximity signal; and

linearizing the digital signal to a full-scale range of the analog proximity signal to thereby enhance a resolution of the received output signal.

7. The method of claim 1 , wherein a source of the non-vibration induced random event generating the spike in the output signal generated by the proximity sensor is attributable to at least one of metal fragments influencing a target surface of a rotating machine being monitored, electrical noise, radio frequency interference, and mechanical vibration unrelated to the rotating machine.

8. The method of claim 1 , further comprising controlling enabling and disabling of suppression of the non-periodic random event as a function of a user-selected parameter received by the proximity system.

9. The method of claim 1 , wherein the output of the proximity system comprises a standard 4-20 mA current output signal.

10. The method of claim 1 , wherein the prescribed level to which the output of the proximity system is set when a spike is detected in the output signal generated by the proximity sensor is less than a level of the output signal during normal vibration of a target surface being monitored.

11. An apparatus for suppressing a non-vibration induced event in a proximity system, the apparatus comprising:

memory; and

at least one processor coupled with the memory, the at least one processor being configured: to receive an output signal generated by a proximity sensor in the proximity system and to monitor at least a magnitude of the output signal; to determine whether a spike having a magnitude exceeding a prescribed threshold value has occurred in the received output signal; to set an output of the proximity system to a prescribed level for a prescribed duration of time when a spike in the received output signal is detected; to determine whether the output signal generated by the proximity sensor meets one or more prescribed criteria indicative of a shutdown condition when the prescribed duration of time has elapsed; to set the output of the proximity system to a level exceeding an alarm threshold of the proximity system when it is determined that the output signal generated by the proximity sensor meets said prescribed criteria indicative of a shutdown condition; and to release suppression of the output of the proximity system when it is determined that the output signal generated by the proximity sensor fails to meet at least one of said prescribed criteria, thereby indicating that the spike in the output signal generated by the proximity sensor was caused by a non-vibration induced random event.

12. The apparatus of claim 11 , wherein to determine whether the output signal generated by the proximity sensor meets said one or more prescribed criteria indicative of a shutdown condition, the at least one processor is further configured to determine whether a magnitude of the spike in the received output signal exceeds a prescribed threshold value, and to determine whether a duration of the spike exceeds a prescribed time.

13. The apparatus of claim 11 , wherein to release suppression of the output of the proximity system, the at least one processor is further configured to set the output of the proximity system equal to an actual level based on the output signal generated by the proximity sensor.

14. The apparatus of claim 11 , wherein at least one of the prescribed threshold value and the prescribed duration of time are user programmable.

15. The apparatus of claim 11 , wherein the at least one processor is further configured to generate a graphical user interface for presentation to a user, the processor receiving at least one of the prescribed threshold value and the prescribed duration of time selected by the user through the graphical user interface.

16. The apparatus of claim 11 , wherein the at least one processor is further configured to: receive an analog proximity signal from the proximity sensor; to convert the analog proximity signal into a digital signal representing the analog proximity signal; and to linearize the digital signal to a full-scale range of the analog proximity signal to thereby enhance a resolution of the received output signal.

17. The apparatus of claim 11 , wherein the at least one processor is further configured:

to receive, as a user-selectable parameter, an enable signal; and to control enabling and disabling of suppression of the non-periodic random event as a function of the enable signal.

18. The apparatus of claim 11 , wherein the prescribed level to which the output of the proximity system is set by the at least one processor when a spike is detected in the output signal generated by the proximity sensor is less than a level of the output signal during normal vibration of a target surface being monitored.

19. A system for monitoring an operational status of a rotating machine, the system comprising:

at least one proximity sensor operatively coupled with a rotating surface of the rotating machine being monitored, the proximity sensor being configured to generate an output signal indicative of a position of the proximity sensor relative to the rotating surface of the rotating machine; and

a position transmitter coupled with the at least one proximity sensor, the position transmitter comprising at least one processor configured: to receive the output signal generated by the proximity sensor and to monitor at least a magnitude of the output signal; to determine whether a spike having a magnitude exceeding a prescribed threshold value has occurred in the received output signal; to set an output of the position transmitter to a prescribed level for a prescribed duration of time when a spike in the received output signal is detected; to determine whether the output signal generated by the proximity sensor meets one or more prescribed criteria indicative of a shutdown condition when the prescribed duration of time has elapsed; to set the output of the position transmitter to a level exceeding an alarm threshold of the system when it is determined that the output signal generated by the proximity sensor meets said prescribed criteria indicative of a shutdown condition; and to release suppression of the output of the position transmitter when it is determined that the output signal generated by the proximity sensor fails to meet at least one of said prescribed criteria, thereby indicating that the spike in the output signal generated by the proximity sensor was caused by a non-vibration induced random event.

20. A non-transitory computer readable medium storing instructions that, when executed by one or more processors, cause the one or more processors:

to receive an output signal generated by a proximity sensor in a proximity system and to monitor at least a magnitude of the output signal;

to determine whether a spike having a magnitude exceeding a prescribed threshold value has occurred in the received output signal;

to set an output of the proximity system to a prescribed level for a prescribed duration of time when a spike in the received output signal is detected;

to determine whether the output signal generated by the proximity sensor meets one or more prescribed criteria indicative of a shutdown condition when the prescribed duration of time has elapsed;

to set the output of the proximity system to a level exceeding an alarm threshold of the proximity system when it is determined that the output signal generated by the proximity sensor meets said prescribed criteria indicative of a shutdown condition; and

to release suppression of the output of the proximity system when it is determined that the output signal generated by the proximity sensor fails to meet at least one of said prescribed criteria, thereby indicating that the spike in the output signal generated by the proximity sensor was caused by a non-vibration induced random event.