A power switch controller includes a condition detector, a zero crossing detector, a retimer, and a driver. The condition detector detects a change in a sense signal towards a first or second condition. The zero crossing detector detects zero crossings in an AC powerline signal. The power switch controller drives a latching relay that connects a load to powerlines. The power switch controller activates or deactivates the latching relay based on the sensed condition, and retimes activation and deactivation pulses to align the relay contact opening and closing times to coincide with the AC powerline zero crossings, compensating for contact travel times. The activation and deactivation pulses have a duration of max 20 ms, and an amplitude of at least 110% of the maximum sustainable voltage for the relay coil(s). A power-on reset deactivates the relay, aligned with a second AC zero crossing.

A time synchronization method, applied to a power-line communication (PLC) network that includes a head end node and at least one tail end node coupled to the head end node. The method includes the head end node generates data about voltage zero-crossing points based on reference time, where the data about the voltage zero-crossing points includes zero-crossing time points of the voltage zero-crossing points. When a first timing point arrives, the head end node sends first information to the tail end node, where the first information includes a timestamp of a first zero-crossing point, the first zero-crossing point is a voltage zero-crossing point closest to the first timing point, and the timestamp of the first zero-crossing point is used by the tail end node to determine a zero-crossing time point of a second zero-crossing point.

Systems, methods, and processor readable media for distributing digital data and electrical power to a plurality of devices over high-impedance cables are disclosed. Certain embodiments include a gateway device connected to a power source, a first device connected to the gateway device by a cable, the cable being a high-impedance cable having at least two conductive paths, and wherein the first device receives electrical power and digital data from the gateway device via the cable over the same conductive path of the cable, a second device connected to the gateway device by the cable wherein the second device receives power and digital data from the gateway device via the cable over the same conductive path, and wherein the power source provides power to the first and second devices via the cable, and wherein the second device is connected to the gateway device through the first device via a daisy-chain topology.

In one embodiment, a method includes transmitting pulse power on two wire pairs, the pulse power comprising a plurality of high voltage pulses with the high voltage pulses on the wire pairs offset between the wire pairs to provide continuous power, performing low voltage fault detection on each of the wire pairs between the high voltage pulses, and transmitting data on at least one of the wire pairs during transmittal of the high voltage pulses. Data transmittal is suspended during the low voltage fault detection.

A method includes computing electrical phase of electrical metering devices including obtaining data indicating zero-crossing times at first and second metering devices. A time difference between the zero-crossing times may be determined. In a first example, the time difference may be based at least in part on calculations involving a first value of a first free-run timer on a first metering device, a second value of a second free-run timer on a second metering device, the time of reception of a packet, and a latency defined by a time taken for the packet to propagate through at least one layer of at least one of the first metering device and the second metering device. A phase difference between the first zero-crossing and the second zero-crossing may be determined, based at least in part on the determined time difference.

An alternating current (AC) zero-crossing indicator apparatus including a current adjusting circuit for adjusting a DC signal current for a duration of time the same as the duration of a received zero-crossing detection signal. The zero-crossing indicator apparatus additionally includes a voltage retainer for maintaining a constant DC voltage applied to a connected load during the adjusting of the DC signal current. Also included is a zero-crossing sensor for generating a zero-crossing indication signal responsive to sensing of the adjusting of the DC signal current.

A method and a device are disclosed including a PLC node having a synchronizer, a modem with a transceiver, and a computing device coupled with a power line for power line data communications. In various embodiments, a coordinator or Data Concentrator Unit (DCU) coordinates the communication of PLC nodes. The PLC nodes are configured to detect a zero crossing of the power line wave form and transmit or receive data within time slots defined with respect to the detected zero crossing. In other embodiments, the time slots may be synchronized using a frame sync signal, an external signal, or polling. In various embodiments, the time slots may be random access or assigned. In some embodiments, the modem and/or node may be placed in a sleep mode when not communicating to reduce power consumption and be awaken when an allocated time slot is approaching.

A powerline communication (PLC) device can be configured to execute functionality for zero cross sampling and detection. When the PLC device is directly coupled to a high-voltage PLC network, the PLC device can comprise printed safety capacitors in series with a high-voltage input AC powerline signal to safely couple the high-voltage AC powerline signal to the low-voltage processing circuit. The PLC device can also comprise an ADC to sample a scaled AC powerline signal and to obtain zero cross information. When the PLC device is part of an embedded PLC application, dynamic loading can affect the integrity of a low voltage zero cross signal that is used to extract zero cross information. After digitizing the zero cross signal, the PLC device can execute functionality to minimize/eliminate voltage drops caused by dynamic loading and obtain the zero cross information.

A method includes computing electrical phase of electrical metering devices including obtaining data indicating zero-crossing times at first and second metering devices. A time difference between the zero-crossing times may be determined. In a first example, the time difference may be based at least in part on calculations involving a first value of a first free-run timer on a first metering device, a second value of a second free-run timer on a second metering device, the time of reception of a packet, and a latency defined by a time taken for the packet to propagate through at least one layer of at least one of the first metering device and the second metering device. A phase difference between the first zero-crossing and the second zero-crossing may be determined, based at least in part on the determined time difference.

An electrical meter (M) installed at a facility (F) supplied electrical power by a utility's (U) electrical distribution system (EDS) utilizes a two-way automatic communications system (TWACS) for receiving messages from the utility sent over the electrical distribution system using the TWACS. An improvement to the meter comprises reconfiguring existing components installed in the meter to function as an analog-to-digital (ADC) converter so to facilitate processing of powerline waveforms (WF) propagated through the electrical distribution system by application of a signal based detection algorithm. This improves detection of signal elements comprising a message sent via the TWACS and by other means and incorporated in the electrical waveforms thereby reducing occurrence of a false synchronization with the message elements so a content of a message is readily ascertained by the meter.