Multiple-processor digital communication system

Claim 1

A system for communicating among two central consoles and a plurality of local controllers, comprising: first and second central consoles for controlling the communication of said system, said consoles selectively issuing command messages to said controllers and for receiving response messages therefrom; a first two line communication path for selectively transmitting messages in both directions, said first path extending from one central console serially to all of said plurality of controllers; a second two line communication path for selectively transmitting messages in both directions, said second path extending from the other console serially to all of said plurality of controllers, the controllers being connected nearer to said first console via said first path also being connected relatively farther from said second controller via said second path; said central consoles being introduced so that each console is capable of communicating with each controller via each path; each of said communication paths comprises a number of 2-conductor loops which extend between adjacently connected controllers, and between a console and the nearest controller connected thereto, each loop having a current source for the loop, said messages being transmitted in either direction by switching the current flow in the loop and another detecting the switched current flow in the loop; each local controller having means operably connected in each loop that extends to adjacently connected controllers or to a console for switching the current flow in each of the loops and for detecting the switched current flow in each of the loops, each of said switching means and said detecting means comprising opto-isolators having a light emitting diode optically coupled to a photo-transistor.

Claim 2

A system for communicating among two central consoles and a plurality of local controllers, comprising: first and second central consoles for controlling the communication of said system, said consoles selectively issuing command messages to said controllers and for receiving response messages therefrom; a first two line communication path for selectively transmitting messages in both directions, said first path extending from one central console serially to all of said plurality of controllers; a second two line communication path for selectively transmitting messages in both directions, said second path extending from the other console serially to all of said plurality of controllers, the controllers being connected nearer to said first console via said first path also being connected relatively farther from said second controller via said second path; said central consoles being introduced so that each console is capable of communicating with each controller via each path; each of said communication paths comprises a number of 2-conductor loops which extend between adjacently connected controllers, and between a console and the nearest controller connected thereto, each loop having a current source for the loop, said messages being transmitted in either direction by switching the current flow in the loop and another detecting the switched current flow in the loop; each local controller having means operably connected in each loop that extends to adjacently connected controllers or to a console for switching the current flow in each of the loops and for detecting the switched current flow in each of the loops, each of said switching means and said detecting means comprising opto-isolators having a light emitting diode optically coupled to a photo-transistor.

Claim 8

A system for digitally communicating among two central consoles and a plurality of local controllers, comprising: first and second central consoles for controlling the communication therebetween and among a plurality of said local controllers, said central consoles issuing digital command messages to said controllers and receiving digital response messages therefrom; a first communication path for transmitting messages in first and second directions, said first communication path extending from one central console serially to all of said plurality of controllers; a second communication path for transmitting messages in first and second directions, said second path extending from the second central console serially to all of said plurality of controllers, the controllers which are connected nearer to said first console via said first path being relatively farther from said second controller via said second path; said first direction of said first path being in the direction away from said first console and said first direction of said second path being in the direction away from said second console, so that said first direction of said first path is opposite the first direction of said second path; said central consoles being interconnected so that each console is capable of communicating with each controller via each path; each of said local controllers further comprising first means for reclocking messages received from said first and second directions in said first path; second means for reclocking messages received from said first and second directions in said second path; first means for receiving command messages from said first central console on said first path and for generating serial response messages in said second direction on said first path, said means being operably connected to said first reclocking means and being adapted to inhibit the same and prohibit reclocking of messages in response to receiving a blocking signal; second means for receiving command messages from said second control console on said second path and for generating serial response messages on said second path, said means being operably connected to second reclocking means and being adapted to inhibit the same and prohibit reclocking of messages in response to receiving a blocking signal; processing means located in each of said local controllers for communicating with said first and second receiving and generating means and for selectively providing control signals to end point means and for collecting data and status information therefrom, said processing means providing response messages to said generating means when said command messages include a unique address identifying said one of said local controllers, said processing means issuing said blocking signals for said first and second receiving and generating means when said processing means determines that said messages indicate a malfunction is occurring in another one of said local controllers in the system.

Claim 9

A system for digitally communicating among two central consoles and a plurality of local controllers, comprising: first and second central consoles for controlling the communication therebetween and among a plurality of said local controllers, said central consoles issuing digital command messages to said controllers and receiving digital response messages therefrom; a first communication path for transmitting messages in first and second directions, said first communication path extending from one central console serially to all of said plurality of controllers; a second communication path for transmitting messages in first and second directions, said second path extending from the second central console serially to all of said plurality of controllers, the controllers which are connected nearer to said first console via said first path being relatively farther from said second controller via said second path; said first direction of said first path being in the direction away from said first console and said first direction of said second path being in the direction away from said second console, so that said first direction of said first path is opposite the first direction of said second path; said central consoles being interconnected so that each console is capable of communicating with each controller via each path; each of said local controllers further comprising first means for reclocking messages received from said first and second directions in said first path; second means for reclocking messages received from said first and second directions in said second path; first means for receiving command messages from said first central console on said first path and for generating serial response messages in said second direction on said first path, said means being operably connected to said first reclocking means and being adapted to inhibit the same and prohibit reclocking of messages in response to receiving a blocking signal; second means for receiving command messages from said second control console on said second path and for generating serial response messages on said second path, said means being operably connected to second reclocking means and being adapted to inhibit the same and prohibit reclocking of messages in response to receiving a blocking signal; processing means located in each of said local controllers for communicating with said first and second receiving and generating means and for selectively providing control signals to end point means and for collecting data and status information therefrom, said processing means providing response messages to said generating means when said command messages include a unique address identifying said one of said local controllers, said processing means issuing said blocking signals for said first and second receiving and generating means when said processing means determines that said messages indicate a malfunction is occurring in another one of said local controllers in the system.