A round target (also known as a 'puck') is used for reliable position feedback on pneumatic quarter-turn actuators or valves.
The puck is mounted directly on the actuator shaft. It is equipped with two metal screws that are mounted at different heights and offset by 90°. A dual inductive sensor with two integral sensors detects the upper or the lower metal screw and, thus, the "open" or "closed" position of the valve. The system operates without contact or wear and is self-cleaning. It is virtually resistant to external influence and insensitive to mechanical stress such as vibration and shock.