04764868 is referenced by 15 patents and cites 12 patents.

An intelligent input/output system for a programmable controller includes a plurality of input/output (I/O) modules, each of which may be located in proximity to the process being controlled. Each module is interconnected, via a communications link, to a central processor unit (CPU) through an I/O controller. Each module is made up of a plurality of input/output circuits and each may be selectively operated as an input circuit or as an output circuit. The selection is preferably under control of the CPU. Each I/O module includes an operations control unit for controlling each I/O circuit and for providing an exchange of diagnostic and control signals between each I/O circuit and the I/O controller and CPU. Communications between the operations control unit and each I/O circuit is preferably carried out via a pair of conductors, one conductor of which conveys a set of recurring control signals (e.g., in signal frames) and the other of which conveys encoded diagnostic signals.

Title
Distributed input/output system
Application Number
617096
Publication Number
4764868
Application Date
November 17, 1986
Publication Date
August 16, 1988
Inventor
Charles E Konrad
Roanoke
VA, US
William J Ketelhut
Charlottesville
VA, US
Agent
O R Austin
Assignee
General Electric Co
VA, US
IPC
G06F 15/46
G06F 03/05
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