Control signal transmission

摘要

The present invention provides a method and apparatus for transmitting control signals across a power circuit between a controller (48) and one or more slave unit (52, 53) that is connected to the power circuit (41). The method includes the steps of receiving from the controller a control signal in any format, and translating that into an Ethernet format signal. This is then modulating onto the power signal feeding the slave unit, and then filtered from the power signal by the slave unit. The Ethernet signal is translated back to the format generated by the controller; and is sent by a separate circuit to the slave unit to control its operation. The apparatus comprises an encoder (47) associated with the controller (48) to receive the control signal and translate and modulate that signal in an Ethernet form onto the power signal. It further comprise a decoder (50,51) with each slave unit (52,53) that receives and demodulates the Ethernet signal from the power signal and translates it back to the same format as originally transmitted by the controller, for onward transmission to the slave unit by means other than the power circuit.