| 摘要 |
The invention relates to a local area network arrangement for implementing a control system. The local area network arrangement comprises a low-voltage bus (SB) composed of a pair cable (32), functioning as a common transmission path of the network, a plurality of connection units (61) connected to the bus for connecting operating devices (15) to be controlled to the network by means of them, a control unit (11) common to the operating devices, connected to the bus for controlling the operating devices, whereby data is transmitted in the network both from the control unit to the connection units, and from the connection units to the control unit. For accomplishing a solution which is as simple as possible, ensures an advantageous control system, and is suited for transmission of slow data, the control unit (11) sends to the bus a constant-frequency carrier signal, whereby (a) a predetermined number of cycles of the carrier signal form one transmission frame (FR), in which a certain cycle corresponds to each connection unit (61) comprised in the network, and (b) at least part of the cycles of the transmission frame (FR) is used during one half of the cycle for transmitting data to one specific connection unit (61), the other half being used for transmitting power to all connection units (61). |
