Construction of RF Admittance Level Sensor
The RF Admittance Level Sensor, developed by Shenzhen Soway Tech Limited (Soway), is a precision instrument designed for continuous liquid level measurement in industrial applications. Its construction combines robust mechanical design with advanced electronic architecture to ensure stable operation under varying process conditions such as high viscosity, temperature fluctuations, or material buildup.
The sensor is composed of four main parts: the sensing probe, reference shield, electronic module, and protective housing.
Sensing Probe
The sensing probe acts as the primary electrode and is directly immersed in the process medium. It forms part of an electrical network whose admittance varies with the liquid level. Soway offers probes of different lengths (typically 80–3000 mm) and materials to suit various media — from water and oil to viscous chemicals and adhesive fluids. Both integrated and split-type designs are available, the latter providing extended temperature resistance up to 200 °C.
Reference Shield (Guard Electrode)
Surrounding the sensing electrode is a specially designed guard or shield electrode that isolates the measurement signal from mounting structures and tank walls. This shield minimizes the influence of parasitic capacitance and surface coating, ensuring that only genuine level changes affect the admittance measurement. The design effectively eliminates errors caused by electrode fouling or conductive buildup.
Electronic Module
The electronics assembly contains the RF oscillator, signal conditioning circuit, and microprocessor unit.
The oscillator generates a stable radio frequency excitation signal, typically between 15 kHz and 400 kHz, which drives the probe circuit.
The signal conditioning stage simultaneously detects both the capacitive and resistive components of the admittance, allowing accurate compensation for material adhesion or dielectric variation.
The microprocessor converts the processed data into standardized outputs such as 0.5–4.5 VDC, 4–20 mA, or RS485 Modbus digital communication.
The module also supports on-site calibration, enabling zero and span adjustments via push buttons or optional display interfaces.
Housing and Sealing Structure
The entire assembly is enclosed in a durable, IP67-rated housing made from corrosion-resistant materials. The enclosure protects the electronics from vibration, dust, and moisture while ensuring reliable operation under pressure levels up to 3MPa. In addition, the sealing design prevents ingress of process material, guaranteeing long-term stability and maintenance-free operation.
Through this well-engineered construction, the Soway RF Admittance Level Sensor achieves exceptional durability, measurement accuracy, and environmental adaptability. Its non-contact, solid-state design — with no moving or elastic components — ensures dependable performance for continuous level monitoring and control in a wide range of industrial liquids and chemical processes.
