摘要 |
<p>A method is provided for monitoring operation of a valve assembly includes a valve element movable between open and closed stops. A position of the valve element between the stops establishes the extent to which the valve is open. The valve assembly includes a DC motor for moving the valve element in response to an electric signal; a position sensor for detecting an actual position of the valve element; and a controller configured to receive data corresponding to a desired position of the valve element, and to supply a calculated electric signal to the motor to move the valve element from the actual position to the desired position. The method comprises: measuring the electric signal output from the controller for input to the motor when the valve element is stationary, and comparing the measured electric signal with a reference electric signal in order to identify a fault.</p> |