Vibronic Point Level Detection

Vibronic Point Level Detection

Vibronic point level detection uses a vibrating element - commonly a tuning fork or rod - driven at resonance. When the fork becomes covered by liquid or solids, the vibration frequency and/or amplitude changes, and the electronics convert that change into a discrete switching signal. The result is a robust point-level indication that does not require a float, paddle, or conductivity path.

This method is widely used for overfill prevention and critical limit switching because performance is typically stable despite changing media properties and disruptive process conditions. It is often applied as a “second line of defense,” supporting high availability and strong functional safety strategies. Reliable switching can be maintained in the presence of foam, turbulence, external vibration, and build-up that can defeat other point-level principles. Endress+Hauser

Specification focuses on mechanical fit and process compatibility: insertion length, mounting orientation, coating potential, and selection of wetted materials for corrosion, erosion, or hygienic requirements. For solids, attention is given to bulk density, particle size, and the likelihood of bridging forces that could mechanically load the fork. For liquids, nozzle effects and switch point geometry are managed to achieve stable trip behavior.

Typical applications include high-high overfill protection on storage tanks, low-low pump protection in sumps and vessels, leakage monitoring, and limit switching in process skids. In bulk solids, vibronic devices are used in silos containing powdery or fine-grained materials where robust point detection is needed and where dust/hazardous-area constraints exist.

Vibronic switches integrate directly into PLC/DCS discrete inputs and safety loops, including SIL-rated architectures where proof testing and diagnostic coverage are defined. For critical point-level duties requiring high confidence under real-world process variability, vibronic detection remains one of the most dependable switching technologies available.

Field Instruments & Controls, Inc. an exclusive authorized representative of sales and service for Endress+Hauser.