| 摘要 |
For the remote monitoring of electrical apparatus (11, 12, 13) the mains power supply (19, 20, 21) is used to transmit signals from the apparatus to a controlling station (17). Local processing (14, 30) is provided at the apparatus to reduce the amount of data to be transmitted and allow the user to program what parameter(s) it is desired to monitor. Signals imposed onto the mains are at a much higher frequency than the mains supply. An address code unit (34), with breakable wires to set the address, plugs into each local unit (14). To avoid signal conflict, each local unit (14) asks permission to transmit. <IMAGE> |
