RELAY FAILURE DETECTION SYSTEM
First Claim
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1. A relay fault detection system structured to detect relay faults within a switching system, the relay fault detection system comprising:
- a first relay having an input structured to couple to a first signal, and having first and second outputs, the first output coupled to a termination resistor and the second output coupled to an output of the switching system, the first relay structured to couple the first signal to the first output or the second output;
a second relay having an input structured to couple to a second signal, and having first and second outputs, the second output coupled to a termination resistor and the first output coupled to the output of the switching system, the second relay structured to couple the second signal to the first output or the second output;
a control system structured to operate the first and second relays to make exactly one of the first or second signals an active signal on the output of the switching system;
a level detector coupled to the first signal and coupled to the second signal and structured to generate a signal level output from the first signal and from the second signal;
a low threshold detector structured to detect a low signal level output as a signal fault; and
a high threshold detector structured to detect a high signal level output as a relay fault.
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Abstract
A relay fault detection and correction system includes a signal detector structured to measure primary and secondary signals, and generates a fault output signal if the signals appear to be unterminated due to a relay not connecting the signals to the loads. A cycle circuit is structured to cause a relay controller to cycle a potentially under-performing relay between its states a number of times after the signal detector generates the fault output.
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Citations
23 Claims
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1. A relay fault detection system structured to detect relay faults within a switching system, the relay fault detection system comprising:
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a first relay having an input structured to couple to a first signal, and having first and second outputs, the first output coupled to a termination resistor and the second output coupled to an output of the switching system, the first relay structured to couple the first signal to the first output or the second output; a second relay having an input structured to couple to a second signal, and having first and second outputs, the second output coupled to a termination resistor and the first output coupled to the output of the switching system, the second relay structured to couple the second signal to the first output or the second output; a control system structured to operate the first and second relays to make exactly one of the first or second signals an active signal on the output of the switching system; a level detector coupled to the first signal and coupled to the second signal and structured to generate a signal level output from the first signal and from the second signal; a low threshold detector structured to detect a low signal level output as a signal fault; and a high threshold detector structured to detect a high signal level output as a relay fault. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An electronic changeover unit having a set of first inputs and a set of related second inputs, the electronic changeover unit comprising:
a series of channels, in which each channel includes; a first relay having an input structured to couple to a first signal, and having first and second outputs, the first output coupled to a termination resistor and the second output coupled to a channel output, the first relay structured to couple the first signal to the first output or the second output, a second relay having an input structured to couple to a second signal, and having first and second outputs, the second output coupled to a termination resistor and the first output coupled to the channel output, the second relay structured to couple the second signal to the first output or the second output, a control system structured to operate the first and second relays to make exactly one of the first or second signals an active signal of the channel output, a level detector coupled to the first signal and coupled to the second signal and structured to generate a signal level output from the first signal and from the second signal, a low threshold detector structured to detect a low signal level output of the level detector as a signal fault, and a high threshold detector structured to detect a high signal level output of the level detector as a relay fault. - View Dependent Claims (10, 11, 12, 13, 14, 15, 23)
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16. A relay fault detection system structured to detect relay faults within a switching system, the relay fault detection system comprising:
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a primary signal receiver for receiving a primary signal and a backup signal receiver for receiving a backup signal; one or more relays coupled between the primary signal receiver, the backup signal receiver, and an output of the switching system; a control system structured to drive the one or more relays to cause one of the primary signal and the backup signal to be an active signal on the output of the switching system, a level detector coupled to the primary signal and coupled to the backup signal and structured to generate a signal level output from the primary signal and from the backup signal; a low threshold detector structured to detect a low signal level output from the level detector as a signal fault; and a high threshold detector structured to detect a high signal level output from the level detector as a relay fault. - View Dependent Claims (17, 18, 20, 21, 22)
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19. A method of operating an electronic changeover unit including a first relay coupled to a first signal input, a second relay coupled to a second signal input, and an output relay coupled to the first relay and the second relay, and in which one of the first signal input or the second signal input is an active signal of the electronic changeover unit, the method comprising:
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detecting that the electronic changeover unit switched which of the first signal input or the second signal input is the active signal; comparing a signal level from the previously in-active signal to a signal level from the presently active signal; determining, based on the comparison, that a relay fault has occurred; and cycling states of at least one of the primary relay, secondary relay, or output relay when the relay fault has occurred.
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Specification