Wetting current diagnostics
First Claim
1. A method of providing wetting current diagnostics for a load control switch, the method comprising:
- changing test switch settings of a detection circuit from an operational configuration to a testing configuration, the test switch settings specifying respective states of first and second test switches of the detection circuit, the first and second test switches being connected to a node of the detection circuit through which, in the operational configuration, a wetting current for the load control switch flows;
determining whether a voltage at the node becomes no longer indicative of the operational configuration as a result of the changed test switch settings;
returning the test switch settings to the operational configuration; and
providing a wetting current fault indication if the voltage at the node fails to return to a level indicative of the operational configuration after returning the test switch settings to the operational configuration.
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Accused Products
Abstract
A method of providing wetting current diagnostics for a load control switch includes changing test switch settings of a detection circuit from an operational configuration to a testing configuration. The test switch settings specify respective states of first and second test switches of the detection circuit. The first and second test switches are connected to a node of the detection circuit through which, in the operational configuration, a wetting current for the load control switch flows. The method includes determining whether a voltage at the node becomes no longer indicative of the operational configuration as a result of the changed test switch settings, returning the test switch settings to the operational configuration, and providing a wetting current fault indication if the voltage at the node fails to return to a level indicative of the operational configuration after returning the test switch settings to the operational configuration.
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Citations
20 Claims
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1. A method of providing wetting current diagnostics for a load control switch, the method comprising:
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changing test switch settings of a detection circuit from an operational configuration to a testing configuration, the test switch settings specifying respective states of first and second test switches of the detection circuit, the first and second test switches being connected to a node of the detection circuit through which, in the operational configuration, a wetting current for the load control switch flows; determining whether a voltage at the node becomes no longer indicative of the operational configuration as a result of the changed test switch settings; returning the test switch settings to the operational configuration; and providing a wetting current fault indication if the voltage at the node fails to return to a level indicative of the operational configuration after returning the test switch settings to the operational configuration. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of providing wetting current diagnostics for a normally open load control switch, the method comprising:
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changing test switch settings of a detection circuit from an operational configuration to a testing configuration, the test switch settings specifying respective states of first and second test switches of the detection circuit, the first and second test switches being connected to a node of the detection circuit through which, in the operational configuration, a wetting current for the load control switch flows when the normally open load control switch is closed; determining, with a comparator of the detection circuit coupled to the node to detect a state of the normally open load control switch in the operational configuration, whether a voltage at the node becomes no longer indicative of the operational configuration as a result of the changed test switch settings; returning the test switch settings to the operational configuration; and providing a wetting current fault indication if the comparator determines that the voltage at the node fails to return to a level indicative of the operational configuration after returning the test switch settings to the operational configuration. - View Dependent Claims (11, 12, 13, 14)
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15. A switch detection unit for a load control switch, the switch detection unit comprising:
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a comparator having an input terminal at a node through which a wetting current flows to reach the load control switch; first and second test switches connected to the node to selectively couple the node to first and second reference voltages, respectively; a controller configured to provide control signaling to the first and second switches, the control signaling being configured to change test switch settings from an operational configuration to a testing configuration, and being further configured to return the test switch settings to the operational configuration; wherein, in the operational configuration, the first test switch is closed and the second test switch is open to support flow of the wetting current through the load control switch when the load control switch is closed; wherein, in the testing configuration, the first test switch is open and the second test switch is closed. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification