Automatic sub-millisecond clock synchronization
First Claim
1. A system for monitoring a plurality of circuit branches coupled to an input line, the system comprising:
- a communication bus;
a controller having a primary clock with a first clock value, the controller configured to be coupled to the communication bus and the input line and further configured to sample voltage on the input line based on the first clock value;
a plurality of sensor circuits, each sensor circuit having a secondary clock with a second clock value and each sensor circuit configured to be coupled to the communication bus and at least one of the plurality of circuit branches, wherein each sensor circuit is further configured to sample current in the at least one of the plurality of circuit branches based on the second clock value; and
wherein the controller is further configured to initiate, via the communication bus, synchronization of at least one secondary clock and the primary clock, and to synchronize, via the communication bus, the at least one secondary clock and the primary clock to account for transmission latency in the communication bus,wherein in synchronizing the at least one secondary clock and the primary clock, the controller is further configured to;
calculate at least one Return Trip Time (RTT) from the controller to at least one of the plurality of sensor circuits having the at least one secondary clock; and
transmit at least one synchronization signal from the controller to the at least one of the plurality of sensor circuits to adjust the second clock value of the at least one secondary clock based on the at least one RTT.
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Accused Products
Abstract
According to one aspect, embodiments of the invention provide a system for monitoring a plurality of circuit branches coupled to an input line, the system comprising a communication bus, a controller having a primary clock with a first clock value and configured to sample voltage on the input line based on the first clock value, a plurality of sensor circuits, each sensor circuit having a secondary clock with a second clock value and configured to sample current in the at least one of the plurality of circuit branches based on the second clock value, and wherein the controller is further configured to initiate, via the communication bus, synchronization of at least one secondary clock and the primary clock, and to synchronize, via the communication bus, the at least one secondary clock and the primary clock to account for transmission latency in the communication bus.
92 Citations
19 Claims
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1. A system for monitoring a plurality of circuit branches coupled to an input line, the system comprising:
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a communication bus; a controller having a primary clock with a first clock value, the controller configured to be coupled to the communication bus and the input line and further configured to sample voltage on the input line based on the first clock value; a plurality of sensor circuits, each sensor circuit having a secondary clock with a second clock value and each sensor circuit configured to be coupled to the communication bus and at least one of the plurality of circuit branches, wherein each sensor circuit is further configured to sample current in the at least one of the plurality of circuit branches based on the second clock value; and wherein the controller is further configured to initiate, via the communication bus, synchronization of at least one secondary clock and the primary clock, and to synchronize, via the communication bus, the at least one secondary clock and the primary clock to account for transmission latency in the communication bus, wherein in synchronizing the at least one secondary clock and the primary clock, the controller is further configured to; calculate at least one Return Trip Time (RTT) from the controller to at least one of the plurality of sensor circuits having the at least one secondary clock; and transmit at least one synchronization signal from the controller to the at least one of the plurality of sensor circuits to adjust the second clock value of the at least one secondary clock based on the at least one RTT. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method for monitoring a plurality of circuit branches coupled to a power line, the method comprising:
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coupling a controller to the communication bus and to the power line, the controller having a primary clock with a first clock value; coupling a sensor circuit to each one of the plurality of circuit branches and to a communication bus, each sensor circuit having a secondary clock with a second clock value; sampling, with at least one of the sensor circuits, current in at least one of the plurality of circuit branches based on the second clock value; sampling, with the controller, voltage on the power line based on the first clock value; and synchronizing, with the controller via the communication bus, the at least one secondary clock and the primary clock to account for transmission latency in the communication bus, wherein synchronizing the at least one secondary clock and the primary clock includes; calculating at least one RTT from the controller to at least one sensor circuit having the at least one secondary clock; and transmitting at least one synchronization signal from the controller to the at least one sensor circuit to adjust the second clock value of the secondary clock of the at least one sensor circuit based on the at least one RTT. - View Dependent Claims (15, 16, 17, 18)
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19. A system for monitoring a plurality of circuit branches coupled to an input line, the system comprising:
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a communication bus; a controller having a primary clock having a first clock value, the controller configured to be coupled to the communication bus and the input line and further configured to sample voltage on the input line based on the first clock value; a plurality of sensor circuits, each sensor circuit having a secondary clock with a second clock value and each sensor circuit configured to be coupled to the communication bus and at least one of the plurality of circuit branches, wherein each sensor circuit is further configured to sample current in the at least one of the plurality of circuit branches based on the second clock value; and means for calculating at least one RTT from the controller to at least one of the plurality of sensor circuits having the at least one secondary clock, and for synchronizing, with the controller via the communication bus, the secondary clock of the at least one of the plurality of sensor circuits and the primary clock of the controller to within 0.1 millisecond based on the at least one RTT.
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Specification