Abstract: This monitoring system for photovoltaic power generation includes: a first to n-th power collecting systems each for supplying a power conditioner with collected outputs from plural photovoltaic panels via a connection box; slave devices provided for connection boxes respectively belonging to the first to n-th power collecting systems, each slave device collecting measurement information about power generation and transmitting the collected measurement information by use of a direct current electrical path of the power collecting system thereof; a master device provided at a power collection end on an inlet side of the power conditioner to obtain the measurement information; a system selection unit for selecting one power collecting system upon reception of a selection signal from the master device and causing power line communication to be performed by use of a direct current electrical path of the selected power collecting system; and a monitoring device connected to the master device.

Abstract: This monitoring system for photovoltaic power generation includes: a first to n-th power collecting systems each for supplying a power conditioner with collected outputs from plural photovoltaic panels via a connection box; slave devices provided for connection boxes respectively belonging to the first to n-th power collecting systems, each slave device collecting measurement information about power generation and transmitting the collected measurement information by use of a direct current electrical path of the power collecting system thereof; a master device provided at a power collection end on an inlet side of the power conditioner to obtain the measurement information; a system selection unit for selecting one power collecting system upon reception of a selection signal from the master device and causing power line communication to be performed by use of a direct current electrical path of the selected power collecting system; and a monitoring device connected to the master device.

Abstract: To realize a transmission function of power line communication by a further simplified and cost-effective circuit configuration, in a PLC modem installed in an electric appliance such as a household electrical appliance. A semiconductor switching element that is present on an electric circuit connected to a power line is driven by a modulator unit. The modulator unit controls ON/OFF operations of the semiconductor switching element, to thereby cause a communication signal of a modulated rectangular wave to be output to the power line for a prescribed period.

Abstract: To realize a transmission function of power line communication by a further simplified and cost-effective circuit configuration, in a PLC modem installed in an electric appliance such as a household electrical appliance. A semiconductor switching element that is present on an electric circuit connected to a power line is driven by a modulator unit. The modulator unit controls ON/OFF operations of the semiconductor switching element, to thereby cause a communication signal of a modulated rectangular wave to be output to the power line for a prescribed period.