Level Sensor Selection and Operating Guide
Level sensors detect and measure the level of liquids, solids, or slurries in tanks, silos, and vessels. Selecting the right technology ensures reliable measurement for the application.
I. Technology Selection
- Ultrasonic: Non-contact measurement using sound waves. Suitable for liquids and some solids. Affected by foam, vapor, and dust.
- Radar: Non-contact using microwave pulses. Excellent for harsh conditions, high temperature, and pressure. Not affected by vapor or dust.
- Capacitance: Measures change in capacitance as level changes. Suitable for liquids and solids. Affected by material dielectric constant changes.
- Hydrostatic: Measures pressure at the bottom of the tank. Simple and reliable for clean liquids in vented tanks.
- Vibrating Fork: Point level detection using vibrating tuning fork technology. Reliable for most liquids and solids.
II. Installation Guidelines
- Mount the sensor vertically above the liquid surface for non-contact types
- Avoid installation near fill streams, agitation, or other sources of turbulence
- Ensure the sensor beam angle does not intersect tank walls, ladders, or internal structures
- For pressure-based sensors, install at the lowest point of the tank for full range measurement
- Use stilling wells for applications with turbulence or foam
III. Configuration
- Set the tank height and sensor mounting offset accurately
- Configure the output range and engineering units
- Set the damping time constant to smooth readings, typically 5-30 seconds for level applications
- Configure alarm setpoints for high and low level conditions
IV. Maintenance
- Clean sensor face periodically to prevent buildup
- Verify calibration quarterly using a reference measurement
- Inspect cable connections and enclosure seals
- Check mounting for looseness caused by vibration
