Patent ID: 8104495

Claim:
A method of monitoring a valve control loop having a control valve that is movable between a first position and a shutdown position, a valve controller for controlling actuation of the control valve, a pneumatic line coupled to the valve controller to move the control valve, and a supporting equipment coupled on the pneumatic line to move the control valve, the method comprising: activating the supporting equipment; determining a pressure differential between two distinct locations on the pneumatic line while activating the supporting equipment; and determining an operational characteristic of the supporting equipment based on the pressure differential, wherein determining a pressure differential includes: detecting a first pressure at a first location on the pneumatic line; detecting a second pressure at a second location on the pneuamtic line that is distinct from the first location; and calculating a difference between the first pressure and the second pressure, wherein determining an operational characteristic of the supporting equipment includes determining a rate of change of the pressure differential and comparing the rate of change to a threshold rate.