System and Method for Detecting Sensor Leakage

• US 20120038366A1
• Filed: 04/28/2010
• Published: 02/16/2012
• Est. Priority Date: 04/28/2009
• Status: Active Grant

• Current Assignee: National Cheng KUNG University (Government of The Republic of China), Textron Innovations Incorporated (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Froman, Gary S.
• Granted Patent: US 8,860,429 B2
• Time in Patent Office: Days
• US Class Current: 324/537
• CPC Class Codes: G01R 31/008 on air- or spacecraft, railway rolling stock or sea-going vessels
• CPC Class Codes: G01R 31/2829 Testing of circuits in sensor or actuator systems testing of apparatus for measuring electric or magnetic variables G01R35/00; testing of indicating or recording apparatus G01D; in airbag systems B60R21/0173; checking gas analysers G01N33/007; monitoring or fail-safe circuits for electromagnets H01F7/1844
• CPC Class Codes: G01R 31/52 Testing for short-circuits, leakage current or ground faults

Abstract

A test system for testing a sensor system includes a high-impedance resistor for forming a voltage divider with any corrosion or foreign substance that might be present between a signal conductor and a ground conductor. While a voltage is applied across the voltage divider, the voltage can be measured across the high-impedance resistor for determining whether an undesirable amount of conductance exists between the signal wire and ground. The test system also includes switching means for switching between any number of signal wires of a system undergoing testing.

Claims

1. A sensor test system, comprising:

a case configured to house a circuit;

a power source for producing a voltage;

a cable electrically connecting a first sensor to the circuit;

the first sensor comprising a first pin and a grounded connector shell;

wherein the circuit comprises;

a high-impedance resistor connected between the power source and the first pin;

a first voltage test point and a second voltage test point across the high-impedance resistor;

a return line from the grounded connector shell to the power source, such that the voltage produced from the power source renders a contaminant conductive, in that the contaminant provides conductive path between the first pin and the grounded connector shell, while the contaminant also provides a contaminant resistance;

wherein interpretation of a measured voltage between the first voltage test point and the second voltage test point provides an indication of the contaminant due to the contaminant resistance affecting the measured voltage.

2. The sensor test system of claim 1, wherein the voltage is approximately 28 volts.

3. The sensor test system of claim 1, wherein the first sensor further comprises a second pin.

4. The sensor test system of claim 3, wherein the first pin and the second pin are electrically tied together within the circuit so as to prevent damage to the first sensor during a test procedure.

5. The sensor test system of claim 1, further comprising:

a voltmeter for measuring the voltage across the first voltage test point and the second voltage test point.

6. The sensor test system of claim 5, wherein the voltmeter is external to the case.

7. The sensor test system of claim 1, further comprising:

a second sensor connected to the circuit with the cable;

a switch for selectively changing electrical connectivity of the circuit between the first sensor and the second sensor.

8. The sensor test system of claim 1, wherein the high-impedance resistor is between 100 k Ohms and 1 M Ohms.

9. The sensor test system of claim 1, wherein the indication of the contaminant represents a quantity of the contaminant.

10. The sensor test system of claim 1, wherein the indication of the contaminant represents a presence of the contaminant.

11. The sensor test system of claim 1, further comprising:

a built-in processor for determining whether the indication of the contaminant represents an unacceptable amount of the contaminant.

12. A tester for detecting contamination in a sensor, the tester comprising:

a case for housing a circuitry;

a cable for connecting a plurality of sensor lines, the sensor lines being in a connector shell, from the sensor to the circuitry, the circuitry comprising;

a conductive connection between each of the plurality of sensor lines together so that each of the plurality of sensor wires are at the same electrical potential, thus protecting the sensor during operation of the tester;

a high-impedance resistor conductively connecting a voltage source and the plurality of sensor lines;

a first voltage test point and second voltage test point across the high-impedance resistor; and

a return line from the connector shell to the voltage source;

wherein the tester is configured such that a presence of a contamination in the connector shell acts to complete the circuitry by providing a conductive path between the voltage source and the plurality of sensor lines, such that current flow in the circuitry indicates the presence of the contamination in the connector shell.

13. The tester according to claim 12, wherein an interpretation of a measured voltage between the first voltage test point and the second voltage test point indicates an amount of resistance provided by the contamination.

14. The tester according to claim 13, further comprising:

a processor for determining whether the amount of contamination exceeds a threshold amount.

15. A method for detecting a leakage in a sensor with a tester, comprising:

using a circuitry in the tester to electrically couple a plurality of sensor wires, the sensor wires being located in a connector shell;

applying a source voltage to the circuitry, the circuitry including a high-impedance resistor located between the plurality of sensor wires and the source voltage, the circuitry being configured such that a contamination located in the connector shell becomes conductive upon applying the source voltage;

taking a voltage reading across the high-impedance resistor; and

interpreting the voltage reading so as to detect determine an amount of the leakage resulting from the contamination.

16. The method according to claim 15, wherein the interpreting the voltage reading includes using a look-up table, the look-up table having predetermined relationships between the voltage readings and a resistance, the resistance being an indication of an extent of the leakage.

17. The method according to claim 15, wherein the interpreting the voltage reading includes using a processor in the tester, the processor being configured to use an internal look-up table for calculating an extent of the leakage.

18. The method according to claim 17, wherein the processor is configured to output a pass/fail reading on a display of the tester.

19. The method according to claim 15, wherein the taking a voltage reading includes using an external volt-meter to take the voltage reading across the high-impedance resistor.

20. The method according to claim 15, wherein the applying the source voltage to the circuitry includes switching on a power switch which applies the source voltage from at least one battery in the tester.