The RF admittance level switch is based on radio frequency (RF) capacitor technology. A radio frequency is applied to the probe and continuous analysis determines the effects caused by the surrounding environment. The energized probe and the container wall form the two pole plates of the capacitor. The insulator of the probe and the surrounding air become dielectric materials. All materials have a dielectric constant that is greater than air. When air is replaced by any other material, the capacitance The effect is strengthened, which changes the impedance of the application, that is, the change in capacitance causes a change in impedance. This effect is measured by the circuit and compared with a reference established by the sensitivity setting (circuit).
The correct sensitivity setting will affect the correct change of the sensor output. The anti-adhesion circuit of the probe can make the measurement circuit ignore the material accumulated on the probe, otherwise it will cause the failure of sensitivity. The anti-stick circuit is excited with the same radio frequency potential as applied to the sensing probe. Because the current cannot flow at the same potential, the anti-adhesion circuit blocks the current that usually flows from the energized probe through the accumulated material to the container wall. This measures the material surrounding the energized probe, not the accumulated material.
