Methods and apparatus to communicatively couple on/off valves to controllers in a process control system

摘要

An apparatus comprising a first interface configured to receive a command signal and send a feedback signal to a termination module 124; a second interface to receive position information, from a proximity sensor, about the state of an on/off valve 202; and a communications processor to process the signals; wherein the feedback signal is based on the position information and sent in response to the command signal. There may be a third interface configured to send the control signal to a solenoid 210 which actuates the valve. The position information may comprise discrete inputs from the proximity sensors indicative of if the valve is open or closed. There may be a housing to contain the first and second interfaces and the communications processor and the housing is physically coupled to the on/off valve. The command signal may be received via the same conductor as the feedback signal is sent down.