Hybrid optical/electrical data highway

Claim 2

A communications system for a large number of widely spaced control stations a different selected one of which may be operating as a transmitting station at different times, comprising: local data transmission networks having two metal wired interconnections providing redundant multi-drop communication channels between all of the control stations of a group determined by geographical location; a global data highway having two optical communication channels each forming a ring for providing redundant signal transmission completely around said rings in opposite directions between the transmission networks of said groups; an optical-electrical interface for each of said groups interposed in each ring for coupling each metal wired interconnection to a separate one of said optical channels, said interfaces each including an optical detector and an optical transmitter connected to provide for transmission of the data received by the detector so that data will flow completely around said global rings in opposite directions; and means for disabling said connection between the detector and transmitter at the interfaces associated with the group of stations which includes the transmitting station while making the connection between the network of the transmitting station and the detector and transmitter of its interface for receipt of said transmitting station of any transmission sent by the transmitting station after the transmission has passed through the optical rings to thereby provide a check on the continuity of said rings.

Claim 3

In a distributed process control system having a large number of widely spaced microprocessor based control stations only a selected one of which is operating as a transmitting station at any one time, a communication system comprising: local data transmission networks having duplicate metallic wiring providing redundant multi-drop communication channels between all of the control stations of a geographically determined group; a global data highway having two optical communication channels each forming a ring for providing redundant signal transmission completely around said rings in opposite directions to interconnect the networks of each of said groups; and an optical-electrical interface for each of said groups inserted to be in series in said rings for coupling signals from each metal wired network to a separate one of said optical channels, said interface including: optical detectors for receiving optical data from each optical channel and converting it to corresponding electrical data signals; optical transmitters for converting electrical data signals to optical data on an optical channel; control elements each connecting corresponding detectors and transmitters to provide repeater operation in each channel and operable upon receipt of a control signal from a transmitting station of the associated group of stations to disconnect the detector from the transmitter to halt said repetition; a connection between a first line of each of the duplicate wiring of the local network and the output of the corresponding detectors to return in duplicate transmitted signals to the transmitting station; a connection between a second line of each of the duplicate wiring of the local network and the input of the corresponding transmitters to carry transmitted signals from the transmitting station to the transmitters for propagation of the optical channels and to also provide for reception of signals transmitted from other groups; and a connection between a third line of each of the duplicate wiring of the local network and the corresponding control element to carry said control signals to said control element.

Claim 4

In a distributed process control system having a large number of widely spaced microprocessor based control stations only a selected one of which is operating as a transmitting station at any one time, a communication system comprising: local data transmission networks having duplicate metallic wiring providing redundant multi-drop communication channels between all of the control stations of a geographically determined group; a global data highway having two optical communication channels each forming a ring for providing redundant signal transmission completely around said rings in opposite directions to interconnect the networks of each of said groups; and an optical-electrical interface for each of said groups inserted to be in series in said rings for coupling signals from each metal wired network to a separate one of said optical channels, said interface including: optical detectors for receiving optical data from each optical channel and converting it to corresponding electrical data signals; optical transmitters for converting electrical data signals to optical data on an optical channel; control elements each connecting corresponding detectors and transmitters to provide repeater operation in each channel and operable upon receipt of a control signal from a transmitting station of the associated group of stations to disconnect the detector from the transmitter to halt said repetition; a connection between a first line of each of the duplicate wiring of the local network and the output of the corresponding detectors to return in duplicate transmitted signals to the transmitting station; a connection between a second line of each of the duplicate wiring of the local network and the input of the corresponding transmitters to carry transmitted signals from the transmitting station to the transmitters for propagation of the optical channels and to also provide for reception of signals transmitted from other groups; and a connection between a third line of each of the duplicate wiring of the local network and the corresponding control element to carry said control signals to said control element.