Remote control system for selective load switching, specifically for automotive vehicles

Claim 1

Remote control system for selection of at least one of a plurality of selectively switchable loads (122) from a central station (110) comprising a bus system (106) having a clock bus (117) and a load switching control bus (129), connected to the central station (110) and to the switchable loads; the central station having a clock source (112); a cyclically operated address counter (115), controlled by the clock source (112), the address counter (115) selecting from said clock pulses a train of a predetermined number of clock pulses to form a selection cycle and a control signal separating sequential selection cycles; means (187) controlled by the address counter (115) connecting clock pulses to the clock bus (117) during a selection portion of the selection cycle and blocking pulses from the clock bus during another portion to thereby form a control signal, defined by a pause in the clock pulses on the clock bus (117) within the selection cycle extending over a predetermined number of clock pulses; a plurality of selectively operable load control switch means (123) to selectively address selected loads and command occurrence of a switching function, the load switch means decoding selected selection pulses corresponding to selected counts of the address count (115) during any selection cycle, for application of said selected pulses to the control bus (129) to address a selected load (122); the loads (122) each including a receiver (111) connected to the clock bus (117) and the load switching control bus (129) and having a receiver counter (130) connected to and counting in synchronism with clock pulses on the clock bus (117) and a decoding circuit (131, 135) connected to the counter and decoding the count of the counter and being responsive to the address of the selected load; and wherein the selection pulses as determined by said selectively operable load control switch means (123) are transmitted over the control bus (129) during the selection portion of the selection cycle in synchronism with the clock pulses on the clock bus (117), said system comprising, in accordance with the invention, in the central station, a pulse generator (181) connected to the bus system (106) to provide function synchronization pulses, the pulse generator being enabled during the control signal separating sequential selection cycles; controlled switch means (197, 198) connected to the clock bus (117) and to the control bus (129) and (a) operable during the selection portion within a selection cycle to connect clock pulses from said clock source (112) to said clock bus (117) and (b) further operable to connect a predetermined number of clock pulses during the control signal portion within the selection cycle formed by the control pause to said control bus (129); and, in each load receiver (112), a function synchronism detection state (156) including a synchronizing counter and connected to the control bus of the bus system to count in synchronism with the pulses derived from the pulse generator (181) in the central station.