The measurement path is different
An ultrasonic device needs an acoustic path to the surface. Tank obstructions, geometry and the conditions in the headspace belong in its selection review. A contact point switch avoids that distance-measurement path but introduces wetted-material and local-mounting requirements. These are different tradeoffs, not proof that one is always more reliable.
When a point switch may be sufficient
A small day tank requiring only a refill signal may need no continuous measurement. A properly installed point switch can support that task, provided the start/stop differential is handled correctly. A stock tank requiring an operator percentage display still needs a continuous measurement method.
Foam must be described accurately. It may affect an acoustic echo, while an electronic tip may respond to wet foam differently from liquid. Test the state the controller must distinguish.
Evaluate changes to maintenance
Compare access to the sensor, expected deposits, cleaning practices and the ability to test the alarm. Replacing a non-contact instrument with a wetted sensor changes the maintenance procedure and may require a new vessel connection.
What to confirm for your application
- Distance or presence-only requirement
- Headspace and foam conditions
- Wetted-material compatibility
- Installation access
- Control differential and fail response
References
Endress+Hauser — Basics of continuous level measurement
Baumer CleverLevel LBFS datasheet — supplied reference, EN/2018-03-01
Technical guidance. Verify the current order-code documentation and your plant requirements before applying a recommendation.