| 摘要 |
A load 5, such as a measuring and/or controlling device in an industrial control system, at a remote location is energised by power transmitted from a light source 1 via an optical guide 2. The transmitted light power may be constant or modulated and the power to the load 5 may be adjusted by a device 4 between the load 5 and an optical/electrical converter 3 or by varying the light input to guide 2, e.g. by adjusting the duty cycle of a pulsed light source. The guide 2 may also transmit information to or from the load 5. When the load 5 is operated intermittently, the power may be transmitted during the off periods and at a lower level than that consumed by the load during its on periods, a capacitor (39), (Figs. 3,4), or a Ni-Cd battery being provided for energy storage at the load location. The guide 2 may comprise one or more optical fibres or a planar optical guide. A pipe enclosing air or a vacuum may alternatively be used with an incoherent light source. <IMAGE> |
