Patent ID: 8392626
Filing Date: 2013-03-05
Classification: G06F,H04L

Abstract:
1. A programmable channel circuit for coupling signals between field devices and control systems, comprising: a control circuit having at least one bidirectional I/O terminal for coupling to a control system, at least one programming terminal, and one or more processing elements; and an interface circuit having a signal portion and an output circuit portion that includes first and second field terminals for coupling a field device across said first and second field terminals, said signal portion of said interface circuit coupled to said control circuit via said processing elements, wherein said control circuit is operable to respond to a programming signal applied to said programming terminal for automatically selecting one of a plurality of signal modes for said channel circuit, wherein said plurality of signal modes include an analog output mode that delivers analog signals from said control system to said signal portion that are output across said first and second field terminals to said field device, a digital output mode that delivers digital signals from said control system to said signal portion that are output across said first and second field terminals to said field device, an analog input mode that receives analog signals from said field device across said first and second field terminals to said signal portion for delivery to said control system, and a digital input mode that receives digital signals from said field device across said first and second field terminals to said signal portion for delivery to said control system, wherein said control circuit provides separate connections to said interface circuit including to independent signal paths for said signals associated with at least said analog output mode, at least one of said analog input mode and said digital input mode, and said digital output mode, and wherein said interface circuit includes a current source in a signal path for at least two of said analog input mode, said digital input mode and said analog output mode.