Smart sensor system for diagnostic monitoring

• US 5,005,142 A
• Filed: 07/24/1989
• Issued: 04/02/1991
• Est. Priority Date: 01/30/1987
• Status: Expired due to Fees

• Current Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Original Assignee: Westinghouse Electric Corporation (Paramount Global (f/k/a ViacomCBS Inc.))
• Inventors: Bednar, Fred H., Ciaramitaro, William, Gisoni, Gregory A., Hughes, Francis R., Smith, John R., Oblak, Tod A., Lipchak, John B.
• Primary Examiner(s): Dixon, Joseph L.
• Application Number:
  US07/386,008
• Time in Patent Office: 617 Days
• Field of Search: 364/550, 364/551.01, 364/556, 364/571.07, 364/138, 364/184, 364/186, 364/553, 364/724, 364/825, 73/112, 73/117.2, 73/767, 340/501, 376/207, 376/216, 376/217, 376/245, 376/259, 371/3, 371/22.5
• US Class Current: 702/183
• CPC Class Codes: G06F 11/0709 in a distributed system consisting of a plurality of standalone computer nodes, e.g. clusters, client-server systems
• CPC Class Codes: G06F 11/0736 in functional embedded systems, i.e. in a data processing system designed as a combination of hardware and software dedicated to performing a certain function testing or monitoring of automated control systems G05B23/02
• CPC Class Codes: G06F 11/0751 Error or fault detection not based on redundancy power supply failures G06F1/30; network fault management H04L41/06

Abstract

The present invention is a component monitoring system which includes all sensor and plant component monitoring at distributed plant locations close to the sensors which are the source of the signals to be analyzed. Minimally preconditioned analog sensor signals are multiplexed and further conditioned by a sensor signal preprocessor that adjusts the gain and filters the sensor signals before being applied to an analog-to-digital converter controlled by a data acquisition computer. The analog sensor signals are converted into digital samples and stored in a data memory of a digital signal processor using a direct memory access technique. The data acquisition computer also controls the selection of sensors, gain, etc., based on commands from a controller. The digital signal processor, once sufficient sensor data has been collected, performs appropriate processing using known digital signal processing techniques. This processed data is then sent to the controller for analysis to determine plant component condition. The analysis and processing routines can be changed by downloading a new routine from the controller. Once a sensor signal is processed, the controller selects the next sensor by transmitting an appropriate command to the data acquisition computer.

Claims

1. A smart sensor system, comprising:

one or more sensors for a monitored component;

a remote processor for processing and analyzing sensor signals from said one or more sensors;

a communication link connected to said remote processor; and

a component monitor connected to said communication link, located physically in association with the monitored component and located physically remotely with respect to said remote processor, said monitor including at least

conditioning and multiplexing means for conditioning and selecting one of the sensor signals, wherein said conditioning and multiplexing means includes at least one sensor preprocessing module, each sensor preprocessing module including at least

a channel selection latch for storing a channel selection signal;

an input multiplexer, operatively connected to said channel selection latch, for receiving the sensor signals from said one or more sensors and for selecting one of the sensor signals as a selected sensor signal based on the channel selection signal;

a gain control latch for storing a gain control value;

a programmable gain control amplifier, operatively connected to said input multiplexer and said gain control latch, for amplifying the selected sensor signal based on the gain control value and for outputting an amplified signal;

a frequency selection latch for storing a frequency selection value;

a switching unit, operatively connected to said frequency selection latch and said programmable gain control amplifier, for receiving the amplified signal and outputting a differential signal;

clock signal generating means for outputting a clock signal in dependence upon the frequency selection value; and

a programmable filter, operatively connected to said switching unit, for lowpass filtering the differential signal based on the clock signal and for outputting a preprocessed sensor signal;

conversion means for converting the sensor signals into digital samples;

signal analysis means for processing and analyzing the digital samples; and

control means for designating selection, conditioning and acquisition of sensor signals, designating a type of analysis performed on the digital samples, performing sensor signal analysis to determine and indicate pending sensor, component and component monitor failure and communicating the results of the analysis to said remote processor over said communications link.

2. A system as recited in claim 1,

wherein said conversion means includes a sampling control computer, and

wherein the gain control value and the frequency selection value are determined by said sampling control computer.

3. A system as recited in claim 1, wherein said clock signal generating means selects a clock frequency for the clock signal from a plurality of predetermined clock frequencies in dependence upon the frequency selection value stored in said frequency selection latch.

4. A system as recited in claim 2, wherein said sampling control computer comprises:

means for receiving a command;

means for determining whether the command indicates at least one of the channel selection signal, the frequency selection value and the gain control value;

means for setting the frequency selection signal in said frequency selection latch;

means for setting the gain control value in said gain control latch; and

means for setting the channel selection signal in said channel selection latch.

5. A system as recited in claim 4,

wherein said conversion means further comprises first and second sample and hold circuits for sampling and holding preprocessed sensor signals, and

wherein said sampling control computer further comprises:

means for determining whether the command requests sampling of a single channel or dual channels; and

means for selecting, when the command requests sampling of the signal channel, one of said first and second sample and hold circuits to perform sampling of the preprocessed sensor signal.

6. A system as recited in claim 5,

wherein said conversion means further comprises analog-to-digital conversion means, operatively connected to said first and second sample and hold circuits and said sampling control computer, for receiving the preprocessed sensor signal and converting the preprocessed sensor signal into a digital sample, and

wherein said signal analysis means comprises a digital signal processor operatively connected to said analog-to-digital conversion means, for processing the digital samples based on processing commands provided by said control means.

7. A smart sensor system, comprising:

one or more sensors for a monitored component;

a remote processor for processing and analyzing sensor signals from said one or more sensors;

a communication link connected to said remote processor; and

a component monitor connected to said communication link, located physically in association with the monitored component and located physically remotely with respect to said remote processor, said monitor component including conditioning and multiplexing means for conditioning and selecting one of the sensor signals, said conditioning and multiplexing means includes at lest one sensor preprocessing module, each sensor preprocessing module includes

a channel selection latch for storing a channel selection signal;

an input multiplexer, operatively connected to said channel selection latch, for receiving the sensor signals from said one or more sensors and for selecting one of the sensor signals as a selected sensor signal based on the channel selection signal;

a gain control latch for storing a gain control value;

a programmable gain control amplifier, operatively connected to said input multiplexer and said gain control latch, for amplifying the selected sensor signal based on the gain control value and for outputting an amplified signal;

a frequency selection latch for storing a frequency selection value;

a switching unit, operatively connected to said frequency selection latch and said programmable gain control amplifier, for receiving the amplified signal and outputting a differential signal;

clock signal generating means for outputting a clock signal in dependence upon the frequency selection value; and

a programmable filter, operatively connected to said switching unit, for lowpass filtering the differential signal based on a clock signal and for outputting a preprocessed sensor signal;

conversion means for converting the sensor signals into digital samples, said conversion means includes first and second sampling and hold circuits, and a sampling control computer for determining the gain control value and the frequency selection value, said sampling control computer comprises includes

means for receiving a command;

means for determining whether the command indicates at least one of the channel selection signal, the frequency selection value and the gain control value;

means for setting the frequency selection signal in said frequency selection latch;

means for setting the gain control value in said gain control latch;

means for setting the channel selection signal in said channel selection latch;

means for determining whether the command requests sampling of a single channel or dual channels; and

means for selecting, when the command requests sampling of the signal channel, one of said first and second sample and hold circuits to perform sampling of the preprocessed sensor signal;

signal analysis means for processing and analyzing the digital samples; and

control means for designating selection, conditioning and acquisition of sensor signals, designating a type of analysis performed on the digital samples, performing sensor signal analysis to determine and indicate pending sensor, component and component monitor failure and communicating the results of the analysis to said remote processor over said communications link.

8. A smart sensor system, comprising:

one or more sensors for a monitored component;

a remote processor for processing and analyzing sensor signals from said one or more sensors;

a communication link connected to said remote processor;

a component monitor connected to said communication link, located physically in association with the monitored component and located physically remotely with respect to said remote processor, said monitor including at least

conditioning and multiplexing means for conditioning and selecting one of the sensor signals, said conditioning and multiplexing means includes at least one sensor preprocessing module, each sensor preprocessing module including at least

a channel selection latch for storing a channel selection signal;

an input multiplexer, operatively connected to said channel selection latch, for receiving the sensor signals from said one or more sensors and for selecting one of the sensor signals as a selected sensor signal based on the channel selection signal;

a frequency selection latch for storing a frequency selection value; and

a switching unit, operatively connected to said frequency selection latch, for receiving the selected sensor signal and outputting a differential signal;

conversion means for converting the sensor signals into digital samples;

signal analysis means for processing and analyzing the digital samples; and

control means for designating selection, conditioning and acquisition of sensor signals, designating a type of analysis performed on the digital samples, performing sensor signal analysis to determine one of pending sensor and component failure, and communicating the results of the analysis to said remote processor over said communications link.

9. A system as recited in claim 8,

wherein said conversion means includes a sampling control computer, and

wherein the frequency selection value is determined by said sampling control computer.

10. A system as recited in claim 9, wherein said sampling control computer comprises:

means for receiving a command;

means for determining whether the command indicates at least one of the channel selection signal and the frequency selection value;

means for setting the frequency selection signal in said frequency selection latch; and

means for setting the channel selection signal in said channel selection latch.

11. A system as recited in claim 10,

wherein said conversion means further comprises first and second sample and hold circuits for sampling and holding preprocessed sensor signals, and

wherein said sampling control computer further comprises:

means for determining whether the command requests sampling of a single channel or dual channels; and

means for selecting, when the command requests sampling of the signal channel, one of said first and second sample and hold circuits to perform sampling of the preprocessed sensor signal.

12. A system as recited in claim 10,

wherein each sensor preprocessing module further comprises:

a gain control latch for storing a gain control value;

a programmable gain control amplifier, operatively connected to said input multiplexer and said gain control latch, for amplifying the selected sensor signal based on the gain control value and for outputting an amplified signal;

clock signal generating means for outputting a clock signal in dependence upon the frequency selection value; and

a programmable filter, operatively connected to said switching unit, for lowpass filtering the differential signal based on the clock signal and for outputting a preprocessed sensor signal, and

wherein said switching unit receives the amplified signal and outputs the differential signal.

13. A system as recited in claim 12, wherein said clock signal generating means selects a clock frequency for the clock signal from a plurality of predetermined clock frequencies in dependence upon the frequency selection value stored in said frequency selection latch.

14. A system as recited in claim 8, wherein said conversion means comprises:

sampling control means for receiving sensor selection and conditioning information from said control means and providing the information to said conditioning and multiplexing means;

sample and hold means, controlled by said sampling control means, for sampling and holding the sensor signals;

multiplexer means, controlled by said sampling control means, for selecting one of the sampled and held sensor signals;

analog-to-digital conversion means, controlled by said sampling control means, for converting the selected sensor signal into the digital sample; and

transfer means for transferring the digital sample to said signal analysis means.

15. A system as recited in claim 14, wherein said transfer means comprises:

a direct memory access control circuit connected between said sampling control means and said signal analysis means; and

address and data latches connected between said sampling control means, said analog-to-digital conversion means and said signal analysis means.

16. A system as recited in claim 8, wherein said signal analysis means comprises:

storage means for storing the digital samples; and

a digital signal processor connected to said storage means and processing the digital samples based on processing commands provided by said control means.

17. A system as recited in claim 8, wherein said control means comprises:

a control processor, connected to said conversion means and said signal analysis means, for providing processing commands to said signal analysis means and sensor selection and conditioning information to said conversion means and for performing analysis of outputs produced by said signal analysis means; and

interface means for communicating between said control processor and the remote processor.

18. A system as recited in claim 8, wherein said control means includes test signal means for providing a test signal to said conditioning and multiplexing means.