Patent ID: 7584643

Claim:
Method for testing the functionality of a valve actuator movable along an actuated path in an actuating system in a safety-oriented circuit in which the partial stroke test method is used, a drive for driving a valve rod drive element ( 8 ) which includes a spindle, said valve rod drive element movable over a portion of its actuating path to test functionality, comprising the steps of: driving said actuator within permitted limits to prevent the actuating system from closing too far; limiting said actuating path of said valve rod drive element ( 8 ) with a mechanical stop ( 15 ), said mechanical stop includes a movable cam ( 16 ) which engages said spindle of said valve rod drive element ( 8 ), said cam ( 16 ) is moved by a pneumatic cylinder ( 17 ); and, pushing said mechanical stop ( 15 ) and said cam ( 16 ) into said actuating path of said valve rod drive element ( 8 ) so that a maximum test stroke or a maximum test angle is not exceeded.