Solid state gas detection sensor diagnostic

• US 9,709,544 B2
• Filed: 02/13/2015
• Issued: 07/18/2017
• Est. Priority Date: 02/14/2014
• Status: Active Grant

• Current Assignee: Rosemount Incorporated (Emerson Electric Company)
• Original Assignee: Rosemount Analytical, Inc. (Emerson Electric Company)
• Inventors: Kozlow, Henryk, Oleszczuk, Lucjan Antoni
• Primary Examiner(s): Rogers, David A
• Application Number:
  US14/621,706
• Publication Number:
  US 20150233880A1
• Time in Patent Office: 886 Days
• CPC Class Codes: G01N 27/12 of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid , for detecting components in the fluid
• CPC Class Codes: G01N 33/0006 Calibrating gas analysers
• CPC Class Codes: G01N 33/007 Arrangements to check the analyser calibrating gas analysers G01N33/0006

Abstract

A metal oxide semiconductor-based toxic gas detector is provided. The metal oxide semiconductor-based detector includes a metal oxide semiconductor-based gas sensor that has an electrical characteristic that varies with concentration of a toxic gas. Measurement circuitry is coupled to the metal oxide semiconductor-based gas sensor and is configured to measure the electrical characteristic and provide a digital indication of the measured electrical characteristic. A controller is coupled to the measurement circuitry and is configured to provide a toxic gas output based on the digital indication. The controller is also configured to provide a diagnostic output relative to the metal oxide semiconductor-based sensor based on fluctuations of the measured electrical characteristic over time.

Claims

1. A metal oxide semiconductor-based toxic gas detector comprising:

a metal oxide semiconductor-based gas sensor, the gas sensor having an electrical characteristic that varies with a concentration of a toxic gas;

measurement circuitry coupled to the metal oxide semiconductor-based gas sensor, the measurement circuitry being configured to measure the electrical characteristic and provide a digital indication of the measured electrical characteristic; and

a controller coupled to the measurement circuitry and configured to provide a toxic gas output based on the digital indication, the controller being further configured to detect a fluctuation in measured digital indications of the measured electrical characteristic over a period of time, and, based on the detected fluctuation, provide a diagnostic indication relative to the metal oxide semiconductor-based sensor.

2. The metal oxide semiconductor-based toxic gas detector of claim 1, and further comprising communication circuitry coupled to the controller and configured to communicate in accordance with a process industry standard communication protocol.

3. The metal oxide semiconductor-based toxic gas detector of claim 2, wherein the communication circuitry is wireless communication circuitry.

4. The metal oxide semiconductor-based toxic gas detector of claim 1, wherein the controller is coupled to memory that stores a plurality of digital indications and wherein the controller processes the plurality of digital indications in order to determine a level of fluctuations.

5. The metal oxide semiconductor-based toxic gas detector of claim 4, wherein the processing includes determining a statistical quantity relative to the plurality of digital indications.

6. The metal oxide semiconductor-based toxic gas detector of claim 5, wherein the statistical quantity is a fluctuation characteristic obtained digitally.

7. The metal oxide semiconductor-based toxic gas detector of claim 4, wherein the level of fluctuations is compared to a pre-determined threshold in order to generate the diagnostic indication.

8. The metal oxide semiconductor-based toxic gas detector of claim 7, wherein the threshold is related to a type of the metal oxide semiconductor-based toxic gas sensor.

9. The metal oxide semiconductor-based toxic gas detector of claim 7, wherein the diagnostic indication is communicated over a process communication loop or segment.

10. The metal oxide semiconductor-based toxic gas detector of claim 7, wherein the diagnostic indication is provided locally by the detector.

11. A method of operating a toxic gas detector having a metal oxide semiconductor-based toxic gas sensor, the method comprising;

obtaining a sequence of measurements of an electrical characteristic of the metal oxide semiconductor-based toxic gas sensor;

processing, using a controller of the toxic gas detector, the sequence of measurements of electrical characteristics to detect a fluctuation in the measurements;

providing a toxic gas detector output based on at least one of the electrical characteristic measurements; and

generating a diagnostic output based on the detected fluctuations, and wherein diagnostic indication comprises a detected stale sensor.

12. The method of claim 11, wherein generating the diagnostic output based on the fluctuations includes calculating a statistical quantity of the sequence of measurements.

13. The method of claim 12, wherein the statistical quantity is indicative of a fluctuation characteristic obtained digitally.

14. The method of claim 12, wherein the statistical quantity is compared to a pre-determined threshold in order to determine whether to generate the diagnostic output.

15. The method of claim 11, wherein the diagnostic output is communicated over a process communication loop or segment.

16. The method of claim 11, wherein the diagnostic output is communicated wirelessly.

17. The method of claim 11, wherein the diagnostic output is communicated locally by the toxic gas detector.