| 摘要 |
PROBLEM TO BE SOLVED: To enable integrally monitoring the operation states of electric apparatuses installed inside a building or a floor.SOLUTION: By the connection of one or a plurality of communication devices and electric apparatuses (which are generically referred to as apparatuses 12) to power lines 11 in a building, in each apparatus 12, a resonant circuit (resonant circuit unit) 14, which has a specific resonant frequency different from one apparatus 12 to another and produces minimum impedance at the resonant frequency thereof, is connected in advance between power lines 13 of the apparatus 12 in a manner to be connected to the power lines 11 in the building only when the apparatus 12 is in an operation state. The impedance of the power line 11 in the building is measured on a frequency-by-frequency basis, and a frequency that produces reduced impedance caused by the resonance with the resonant circuit is detected. An apparatus 12 corresponding to the detected frequency is discriminated as an apparatus in the operation state. |
