How the RF Admittance Level Sensor Measures Liquid Level

The RF Admittance Level Sensor from Shenzhen Soway Tech Limited (Soway) is an industrial-grade sensor designed for accurate and reliable liquid level measurement. Its operation is based on detecting changes in electrical admittance—a combination of capacitance and resistance—between the sensing probe and the liquid. This approach enables precise monitoring of various liquids, including water, oils, viscous substances, and chemical solutions.

Principle of Measurement

The sensor’s probe is immersed in the liquid medium, and as the liquid level changes, the electrical characteristics of the interface between the probe and the liquid also change. Specifically:

Capacitance: The capacitance between the probe and the liquid varies proportionally with liquid height.

Resistance: The resistive component changes according to the dielectric properties of the liquid.

By continuously monitoring these two parameters, the sensor generates a signal that accurately corresponds to the liquid level. This dual-parameter measurement ensures that the sensor maintains high accuracy even when the liquid surface may have minor coatings or other effects that could otherwise interfere with simple capacitive measurement.

Output Signals

The sensor converts these admittance changes into standard output signals, which are compatible with industrial monitoring and control systems. The available output options include:

Analog voltage output: 0.5–4.5 V DC

Analog current output: 4–20 mA

Digital communication: RS485 Modbus

These outputs allow for real-time monitoring of liquid level, making the sensor suitable for integration with various data acquisition and control systems. The outputs directly reflect the measured liquid level based on the admittance of the medium.

Calibration and Adjustment

The RF Admittance Level Sensor supports on-site calibration, allowing users to adjust measurement parameters according to specific liquids or installation conditions. Calibration functions include:

Zero-point adjustment

Full-scale calibration

Measurement range setting

This feature ensures consistent and repeatable measurement across different operating environments, while maintaining accuracy for a wide range of liquids, including water, oils, viscous substances, and chemical solutions.

Reliability and Durability

The sensor design contains no moving or elastic components, which increases its impact resistance and overall reliability. Its robust construction and simple installation process make it suitable for various industrial environments where liquid level measurement is required.

The RF Admittance Level Sensor from Shenzhen Soway Tech Limited (Soway) measures liquid level by detecting changes in capacitance and resistance at the probe-liquid interface. It provides accurate measurement outputs through analog voltage, analog current, or RS485 digital signals, and supports on-site calibration for range, zero, and full-scale adjustments. With no moving parts and a durable design, it ensures reliable and repeatable measurement for liquids such as water, oils, viscous substances, and chemical solutions.