Patent ID: 8684021

Claim:
A method of monitoring a fluid process control system having a control loop for controlling the flow of a material through a path in the fluid process control system, the control loop including a control valve, a valve actuator, a valve positioner, and one of an emergency shutdown controller and a process controller, the control valve disposed in the path and being movable between an open position and a closed position by the valve actuator, the valve positioner for controlling movement of the control valve and comprising an input receiving a supply pressure and an output connected to a fluid control line coupling the valve positioner to the valve actuator, the method comprising: detecting a first pressure at a location on the fluid control line of the control loop with a first pressure sensor of the valve positioner; adjusting a position of the valve actuator by adjusting a pressure in the fluid control line with the valve positioner based on the first pressure; and detecting a second pressure at a location in the fluid process control system that is external to the control loop with a second pressure sensor of the valve positioner, wherein said detecting a second pressure includes detecting a pressure located at an inlet of the control valve or at an outlet of the control valve; not using the second pressure for control of the control valve, and not using the second pressure for testing of the control valve; and sending a signal representative of the second pressure from the valve positioner to the emergency shutdown controller or process controller over a communication network.