Processing Magazine

New valve position sensors are ideal replacement for mechanical limit switches

September 5, 2007

The Series F31 Valve Position Sensors are just 1.25 inches tall and mount directly to the top plate of any standard pneumatic actuator with just two screws for highly accurate position indication. They feature two electronic switching points integrated into one compact housing, and integral LEDs for quick visual status indication and diagnostics. Additionally, electronic switch contacts facilitate network communication and provide for direct control of a solenoid valve. In contrast, mechanical limit switches always require adjustment during installation and are actuated by an adjustable cam that is prone to needing re-adjustment during its service life. Unlike mechanical limit switches, F31 sensors will not fail over time due to metal fatigue. Additionally, these sensors do not require a bulky and costly metal enclosure to protect them from the environment and to keep unauthorized personnel from tampering with switch settings. F31 valve position sensors may be used on clockwise or counter-clockwise rotating actuators, or mounted onto a manual valve with an optional mounting bracket. Accuracy and repeatability are unaffected by the speed or frequency of the actuator. They are available in 2 and 3-wire DC models, and 4-wire AC/DC models. AS-Interface, Namur, direct solenoid valve connections, and cabled or terminal connections, are also available.