Dimmer control for system having master and slave dimming devices using pulse signalling therebetween

Claim 1

A DIMMING SYSTEM FOR CONTROLLING THE LUMEN OUTPUT OF A PLURALITY OF LAMP BANKS ENERGIZED FROM A SOURCE OF ALTERNATING CURRENT COMPRISING A MASTER DIMMING CIRCUIT FOR A FIRST BANK OF LAMPS INCLUDING INPUT MEANS FOR CONNECTING SAID MASTER DIMMER CIRCUIT TO SAID SOURCE, A FIRST AND A SECOND ELECTRONIC SWITCH MEANS INCLUDING A PHASE SHIFT NETWORK FOR PROVIDING CONTROL VOLTAGE TO OPERATE AT LEAST ONE OF SAID ELECTRONIC SWITCHES DURING AN INTERVAL OF ONE-HALF CYCLE OF SAID ALTERNATING CURRENT, INTENSITY SELECTOR MEANS FOR VARYING THE DURING OF SAID INTERVAL, OUTPUT MEANS FOR COUPLING CURRENT TO SAID FIRST BANK OF LAMPS DURING SAID INTERVAL OF OPERATION OF SAID SWITCHES, AND PULSE DERIVATION MEANS FOR PROVIDING A PULSE OF ELECTRICAL ENERGY IN RESPONSE TO EACH SWITCHING OPERATION BY ONE OF SAID SWITCHES; AND A SLAVE DIMMING CIRCUIT FOR CONTROLLING A SECOND BANK OF LAMPS INCLUDING CONTROL MEANS RESPONSIVE TO SAID PULSE FROM SAID PULSE DERIVATION MEANS TO OPERATE SAID SECOND BANK OF LAMPS FOR A PERIOD CORRESPONDING TO THE PERIOD OF OPERATION OF SAID FIRST BANK OF LAMPS, INCLUDING PULSE-RESPONSIVE MEANS, MEANS CONNECTING SAID PULSE RESPONSIVE MEANS TO THE PULSE DERIVATION MEANS OF SAID MASTER DIMMING CIRCUIT, FURTHER SWITCHES CONNECTED FOR SELECTIVE OPERATION BY SAID PULSE RESPONSIVE MEANS, OUTPUT MEANS FOR COUPLING CURRENT TO THE SECOND LAMP BANK RESPONSIVE TO ENERGIZATION OF SAID FURTHER SWTICHES, AND PULSE DERIVATION MEANS FOR COUPLING A PULSE TO A FURTHER SLAVE DIMMING CIRCUIT RESPONSIVE TO OPERATION OF ONE SAID FURTHER SWITCHES.