The Rosemount 2130 Level Switch is designed using the principle of a tuning fork. A piezo-electric crystal oscillates the forks at their natural frequency. Changes to this frequency are continuously monitored. The frequency of the vibrating fork sensor changes depending on the medium in which it is immersed. The denser the liquid, the lower the frequency.

When used as a low level alarm, the liquid in the tank or pipe drains down past the fork, causing a change of natural frequency that is detected by the electronics and switches the output state.

When the 2130 is used as a high level alarm, the liquid rises in the tank or pipe, making contact with the fork which then causes the output state to switch.

Additional features: Virtually unaffected by turbulence, foam, vibration, solids content, coating products, and liquid properties. The mid-range temperature 2130 is designed for operation in process temperatures from –40 to 356 °F (–40 to 180 °C). The extreme temperature 2130 is designed for operation in process temperatures from –94 to 500 °F (–70 to 260 °C). Electronic self-checking and condition monitoring. The ‘heartbeat’ LED gives status and health information on the 2130. Adjustable switching delay prevents false switching in turbulent or splashing applications. ‘Fast Drip’ fork design gives quicker response time when mounted horizontally, especially with viscous liquids.