Method and system to validate wired sensors

Patent metadata

Field	Value
Publication number	US-9280516-B2
Application number	US-201213440339-A
Country	US
Kind code	B2
Filing date	Apr 5, 2012
Priority date	Apr 7, 2011
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

The present invention provides a method and system using wireless sensors to validate wired sensors used in applications where the requirements on the reliability of wired sensors are stringent. A computing means periodically collects measurements for each variable from the wired and wireless sensors and compares them against an expected value. The expected value is a weighted average of all the measurements for a variable, in which the weight assigned to the measurement from each sensor is determined according to both its reliability and accuracy. As such, measurements are compared with the corresponding expected value for a particular variable. If the difference between a measurement and its corresponding expected value is found to be unacceptable, the validation computer will generate a corresponding alert. Application examples include 1) validating wired sensors used in safety shutdown systems for industrial facilities and 2) validating wired sensors used to monitor storage tanks.

First claim

What is claimed is:

1. A system, for use in a safety shutdown system in an industrial facility, the system for validating at least one wired sensor measuring at least one variable comprising:
(a) at least one wireless sensor for measuring the at least one variable as an at least one wireless sensor measurement, the at least one wireless sensor having built-in computer-executable instructions for self-checking and self-diagnostics;
(b) at least one wired receiver, operatively coupled to the at least one wired sensor, to receive at least one wired sensor measurement from the at least one wired sensor;
(c) at least one wireless receiver, operatively coupled to the at least one wireless sensor to receive the at least one wireless sensor measurement from the at least one wireless sensor; and
(d) a validation computer, operatively coupled to the at least one wired receiver and the at least one wireless receiver, to compare the at least one wired sensor measurement and the at least one wireless sensor measurement to an expected value, such that if at least one measurement is unacceptable, an alert is generated;
wherein the at least one wired sensor measurement is transmitted to a monitoring device that is independent of the validation computer;
wherein the at least one wireless sensor transmits a message to the at least one wireless receiver whenever an abnormality is detected when the computer-executable instructions are executed;
wherein the at least one wired sensor measurement of the at least one variable is a trip variable used by the monitoring device in a shutdown logic of the safety shutdown system for the industrial facility; and
wherein the at least one wireless sensor has a different measurement mechanism than the at least one wired sensor so as to increase reliability of the safety shutdown system through sensor diversity.

2. The system as in claim 1 , wherein the variable is a substance level in a storage tank.

3. The system as in claim 1 , wherein the variable is a level in a liquid storage tank.

4. The system as in claim 1 , wherein the expected value is a weighted average of all the wired and wireless measurements for the variable.

5. The system as in claim 4 , wherein the expected value is determined by assigning a weight to each measurement from each of the at least one wired sensor and the at least one wireless sensor, wherein each assigned weight is determined based on a measured reliability and accuracy of a corresponding sensor.

6. The system as in claim 1 , wherein the expected value is a weighted average of all the wired and wireless measurements for the variable, except the measurement which is to be compared against the expected value.

7. The system as in claim 6 , wherein the expected value is determined by assigning a weight to each measurement from each of the at least one wired sensor and the at least one wireless sensor, except the measurement which is to be compared against the expected value, wherein each assigned weight is determined based on a measured reliability and accuracy of a corresponding sensor.

8. The system as in claim 1 , wherein the at least one wired sensor uses analog signals to transmit measurements.

9. The system as in claim 1 , wherein the at least one wireless sensor uses digital signals to transmit measurements.

10. The system as in claim 1 , further including an isolator between the validation computer and the at least one wired sensor.

11. The system as in claim 1 , further including at least one display that is operatively coupled to the validation computer.

12. The system as in claim 1 , further including at least one audio indicator that is operatively coupled to the validation computer.

13. The system as in claim 1 , further including at least one visual indicator that is operatively coupled to the validation computer.

14. The system as in claim 1 , wherein the validation computer includes a database to record all of the measurements collected.

15. A method, for use in a safety shutdown system in an industrial facility, the method for validating at least one wired sensor measuring at least one variable comprising steps of:
(a) using at least one wireless sensor having built-in computer-executable instructions for self-checking and self-diagnostics, and the at least one wired sensor to collect measurements from the at least one variable;
(b) calculating a weighted average of all of the measurements taken in step (a) as an expected value;
(c) comparing at least one measurement to the expected value;
(d) determining whether a difference between the at least one measurement and the expected value is unacceptable;
(e) in the event that the difference between the at least one measurement and the expected value is unacceptable, an alert is generated and the method returning to step (a); and
(f) in the event that the difference between the at least one measurement and the expected value is acceptable, returning to step (a);
wherein measurements from the at least one variable collected by the at least one wired sensor is transmitted to a monitoring device that is independent of a validation computer performing steps b), c), and d); and
wherein measurements from the at least one variable collected by the at least one wired sensor is a trip variable used by the monitoring device in a shutdown logic of the safety shutdown system for the industrial facility;
wherein the at least one wireless sensor transmits a message to the at least one wireless receiver whenever an abnormality is detected when the computer-executable instructions are executed; and
wherein the at least one wireless sensor has a different measurement mechanism than the at least one wired sensor so as to increase reliability of the safety shutdown system through sensor diversity.

Assignees

• Jiang Jin
• Li Qingfeng
• Univ Western Ontario

Inventors

• Jiang Jin
• Li Qingfeng

Classifications

• H04W84/18

  Self-organising networks, e.g. ad-hoc networks or sensor networks · CPC title

• H04Q9/00 Primary

  Arrangements in telecontrol or telemetry systems for selectively calling a substation from a main station, in which substation desired apparatus is selected for applying a control signal thereto or for obtaining measured values therefrom · CPC title

• H04Q2209/30

  using a wired architecture · CPC title

• H04Q2209/40

  using a wireless architecture · CPC title

• H04Q2209/86

  Performing a diagnostic of the sensing device · CPC title