Safety interlocks for electricity meter control relays
First Claim
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1. In an electricity meter comprising a processor, a memory, a communication interface, and at least one control relay that has a first state in which the control relay is open and a second state in which the control relay is closed, the state of the control relay being controlled by the processor, a method comprising:
- receiving a request via the communications interface to change a state of the at least one control relay;
checking a state of a safety interlock flag stored in the memory of the electricity meter, the safety interlock flag indicating whether or not changes to the state of the at least one control relay are permitted; and
changing the state of the at least one control relay in response to the received request, only if the state of the safety interlock flag indicates that changes are permitted, but otherwise not changing the state of the at least one control relay.
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Abstract
Safety in an electricity metering environment is improved by providing an additional level of safety interlocking to disconnect switches and other control relays in electricity meters.
23 Citations
22 Claims
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1. In an electricity meter comprising a processor, a memory, a communication interface, and at least one control relay that has a first state in which the control relay is open and a second state in which the control relay is closed, the state of the control relay being controlled by the processor, a method comprising:
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receiving a request via the communications interface to change a state of the at least one control relay; checking a state of a safety interlock flag stored in the memory of the electricity meter, the safety interlock flag indicating whether or not changes to the state of the at least one control relay are permitted; and changing the state of the at least one control relay in response to the received request, only if the state of the safety interlock flag indicates that changes are permitted, but otherwise not changing the state of the at least one control relay. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. An electricity meter comprising:
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at least one control relay that has a first state in which the control relay is open and a second state in which the control relay is closed; a memory containing a safety interlock flag having a state that indicates whether or not changes to the state of the at least one control relay are permitted; a communications interface adapted to receive a request to change the state of the at least one control relay; and a processor that controls the state of the control relay, the processor operating to receive a request via the communications interface to change the state of the at least one control relay, to check the state of the safety interlock flag stored in the memory of the electricity meter and to determine therefrom whether or not changes to the state of the at least one control relay are permitted, and to change the state of the at least one control relay in response to the received request, only if the state of the safety interlock flag indicates that changes are permitted, but otherwise to not change the state of the at least one control relay. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification