Control system with time reference for data acquisition

Claim 1

A SUPERVISORY CONTROL SYSTEM WITH WHICH INFORMATION CAN BE GATHERED AT A CENTRAL STATION FROM A PLURALITY OF REMOTE STATIONS BY MESSAGES SENT FROM DIFFERENT REMOTE STATIONS AT DIFFERENT TIMES BUT REPRESENTING CONDITIONS EXISTING AT THOSE REMOTE STATIONS AT THE SAME REFERENCE TIME, SAID SYSTEM INCLUDING IN COMBINATION: (A) A FIRST SUB-SYSTEM ADAPTED TO BE LOCATED AT A CENTRAL STATION AND INCLUDING FIRST TRANSMITTING MEANS, FIRST RECEIVING MEANS, AND FIRST DATA PROCESSING MEANS, (B) A PLURALITY OF SECOND SUB-SYSTEMS ADAPTED TO BE LOCATED RESPECTIVELY AT DIFFERENT REMOTE STATIONS AND EACH INCLUDING SECOND TRANSMITTING MEANS, SECOND RECEIVING MEANS, AND SECOND DATA PROCESSING MEANS, (C) ENCODING MEANS IN SAID FIRST DATA PROCESSING MEANS FOR CAUSING TRANSMISSION OF A UNIQUELY CODED ALLSTATIONS FREEZE COMMAND BY SAID FIRST TRANSMITTING MEANS, (D) DECODING MEANS IN EACH OF SAID SECOND DATA PROCESSING MEANS AND EACH CAPABLE OF DECODING SAID ALLSTATIONS FREEZE COMMAND, (E) TIMING MEANS IN EACH OF SAID SECOND DATA PROCESSING MEANS CONTROLLED BY THE ASSOCIATED DECODING MEANS TO PROVIDE A TIME REFERENCE TIMING CYCLE DURING WHICH INFORMATION MAY BE ACQUIRED BY SAID FIRST SUB-SYSTEM FROM SAID SECOND SUB-SYSTEMS BY SEQUENTIAL INTERROGATION THEREOF, (F) AND STORAGE MEANS IN EACH OF SAID SECOND DATA PROCESSING MEANS CONTROLLED BY SAID DECODING MEANS AND RESPONSIVE TO DECODING OF SAID ALL-STATIONS COMMAND BY SAID DECODING MEANS TO STORE INFORMATION REPRESENTING DIFFERENT CONDITIONS AT A REFERENCE TIME DETERMINED BY RECEIPT OF SAID FREEZE COMMAND REMOTE STATIONS, (G) AND EACH OF SAID TIMING MEANS BEING RESPONSIVE TO DECODING OF SAID ALL-STATIONS FREEZE COMMAND BY SAID DECODING MEANS TO START SAID TIMING CYCLE, AND TO ENABLE SAID STORAGE MEANS TO SUPPLY THE TIME-REFERENCED INFORMATION STORED THEREBY TO THE SECOND TRANSMITTING MEANS ASSOCIATED THEREWITH ONLY DURING SAID TIMING CYCLE.