Distributed bus control system

Claim 2

Distributed bus control system with variable time division for determining the order in which a plurality of stations can communicate messages over a common communication channel, said messages including at least global messages requiring acknowledgement and end-off-transmission messages to inform said stations in the communication system that the transmitting station has ended transmission, characterized by : a communication medium (13,15,17) for supporting the communication of information.between a plurality of stations; a plurality of stations (11,14,16) connoted to said communication medium; each of said stations comprising time slot means (34,36) for determining at least one time slot during which an assigned station can transmit information over said communication medium, each time slot having only one station assigned thereto, transmission control means (32,33) responsive to messages being transmitted over the communication medium and responsive to said time slot means for transmitting messages over said communication medium when it is the turn of each station to transmit, and acknowledgement timermeans (36) for delaying the transmission of any further messages for a predetermined period of time after the transmission of a global message requiring acknowledgement unless said selected station has acknowledged said global message.

Claim 3

Distributed bus control system with variable time division for determining the order in which a plurality of stations can communicate messages over a common communication channel and for reinitializing said system when communication has been quiet beyond a predetermined time period, characterized by: a communication medium (13,15,17) for supporting the communication of information between a plurality of stations; a plurality of stations (11,14,16) connected to said communication medium; each of said stations comprising time slot means (34,36) for determining at least one time slot during which an assigned station can transmit information over said communication medium, each time slot having only one station assigned thereto, transmission control means (32,33) responsive to messages being transmitted over the communication medium and responsive to said time slot means for transmitting messages over said communication medium when it is the turn of each station to transmit, and initializing means (36) responsive when the communication medium has been quiet for a predetermined time period for initiating the transmission of an initializing message over said communication medium, said initializing message having an acknowledger portion requiring a specified station to acknowledge said initializing message, said predetermined time period being different for each station connected to said communication medium.

Claim 4

Distributed bus control system with variable time division for determining the order in which a plurality of stations can communicate messages over a common communication channel and for reinitializing said system when communication has been quiet beyond a predetermined time period, characterized by: a communication medium (13,15,17) for supporting the communication of information between a plurality of stations; a plurality of stations (11,14,16) connected to said communication medium; each of said stations comprising time slot means (34,36) for determining at least one time slot during which an assigned station can transmit information over said communication medium, each time slot having only one station assigned thereto, transmission control means (32,33) responsive to messages being transmitted over the communication medium and responsive to said time slot means for transmitting messages over said communication medium when it is the turn of each station to transmit, and initializing means (36) responsive when the communication medium has been quiet for a predetermined time period for initiating the transmission of an initializing message over said communication medium, said initializing message having an acknowledger portion requiring a specified station to acknowledge said initializing message, said predetermined time period being different for each station connected to said communication medium.

Claim 5

Distributed bus control system with variable time division for determining the order in which a plurality of stations can communicate messages over a common communication channel and for allowing the transmission of plural messages during a time slot assigned to a station, characterized b y: a communication medium (13,15,17) for supporting the communication of information between a plurality of stations; a plurality of stations (11,14,16) connected to said communication medium; each of said stations comprising time slot means (34,36) for determining at least one time slot during which an assigned station can transmit information over said communication medium, each time slot having only one station assigned thereto, transmission control means (32,33) responsive to messages being transmitted over the communication medium and responsive to said time slot -aans for transmitting messages over said communication medium when it is the turn of each station to transmit, message limit memory means (34) for storing a message limit determinative of the number of messages which can be transmitted during any specified time slot assigned to the station, and message counter means (36) for counting the number of messages being transmitted during a specified time slot for terminating transmission wherein the message counter reaches the message limit.

Claim 6

Distributed bus control system with variable time division for determining the order in which a plurality of stations can communicate messages over a common communication channel and for allowing the transmission of plural messages during a time slot assigned to a station, characterized b y: a communication medium (13,15,17) for supporting the communication of information between a plurality of stations; a plurality of stations (11,14,16) connected to said communication medium; each of said stations comprising time slot means (34,36) for determining at least one time slot during which an assigned station can transmit information over said communication medium, each time slot having only one station assigned thereto, transmission control means (32,33) responsive to messages being transmitted over the communication medium and responsive to said time slot -aans for transmitting messages over said communication medium when it is the turn of each station to transmit, message limit memory means (34) for storing a message limit determinative of the number of messages which can be transmitted during any specified time slot assigned to the station, and message counter means (36) for counting the number of messages being transmitted during a specified time slot for terminating transmission wherein the message counter reaches the message limit.

Claim 7

System according to one of claims 1 to 3, characterized in that , said transmission control means comprises a time slot counter (36) which is incremented after the receipt of each end-of-transmission message.

Claim 8

System according to claim 4, characterized in that said transmission control means comprises means (32,33,34) for transmitting messages having a source time slot field containing the time slot of the sending station and wherein said time slot counter is reset to the time slot contained in the source time slot field in messages which contain a source time slot field.

Claim 9

System according to claim 5, characterized in that said transmission control means comprises message limit memory means (34) for storing a message limit equal to the number of messages which can be transmitted by a station during a selected time slot and a message counter (36) for counting the number of messages sent by the station, said transmission control means terminating transmission when said message counter equals said message limit.

Claim 10

System according to claim 6, characterized in that, said transmission control means comprises retransmission limit memory means (34) for storing as a limit the number of times a station can retransmit a message and a retransmission counter for counting the number of times a station attempts to retransmit a message for retransmitting a message, said transmission control means retransmitting a message until the value of said retransmission counter equals said retransmission limit unless the message is acknowledged as being successfully received.

Claim 11

System according to claim 2, characterized in that, said initializing means comprises acknowledgement timer means (36) for delaying the transmission of any further messages for a predetermined period of time after the transmission of an initializing message requiring acknowledgement unless said selected station has acknowledged said initializing message.

Claim 12

System according to claim 8, characterized in that said transmission control means comprises station acknowledgement selection means (36) for selecting the acknowledger station.