What are the principle, application scenarios, and operating conditions of radio frequency admittance level gauges?

RF admittance is a new type of level control technology that evolved from capacitive technology; it prevents material buildup, offers greater reliability and accuracy, and has a wider range of applications, representing an upgrade to capacitive level control techniques. The so-called radio frequency admittance refers to the reciprocal of impedance in electricity; it is composed of resistive, capacitive, and inductive components. Since \"radio frequency\" denotes the high-frequency radio wave spectrum, radio frequency admittance can be understood as the measurement of admittance using high-frequency radio waves. When the instrument is in operation, its sensors create an admittance value with the tank wall and the medium being measured. As the liquid level changes, this admittance value changes accordingly; the circuit unit converts this measured admittance value into a liquid level signal, thereby enabling the measurement of the liquid level. Typical applications: Conductive and insulating liquids – chemical industry, oil fields, water and wastewater treatment; Conductive and insulating liquids – paper manufacturing, pharmaceutical industry, water and wastewater treatment. Powders: Ash, powder – power plants, metallurgy, cement production. Granules: Coal, grains – power plants, metallurgy, grain processing

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Suitable for media with large differences in dielectric constants.

If his probe is contaminated with coal dust, can it still provide accurate measurement results?

The basic measurement principle of the radio frequency admittance level gauge is the same as that of the capacitive level gauge. Since the capacitive electrodes tend to scale and get clogged when used in viscous media, after some time an additional capacitance Cc0 and resistance Rc0 appear; these are composed of many Cc01 to Cc0n. And Rc01～Rc0n. This composition reduces the voltage output from the oscillator to the probe, resulting in errors in the measurement circuit ； At the same time, the presence of Cc0 directly causes measurement errors. The radio frequency admittance level gauge was named thus as it compensates for these deficiencies based on the capacitive level gauge, thereby overcoming the measurement errors caused by deposits on the surface of the liquid. By utilizing radio frequency admittance technology, it goes beyond simply measuring the capacitive reactance of radio frequency capacitance level gauges; impedance is also measured simultaneously. The anti-deposition circuit in the module combines the capacitive reactance data with the impedance data, enabling reliable elimination of the effects of deposits or scaling on the sensor and the container walls. It features a fully electronic design with no movable parts that can wear out or need to be disassembled, resulting in a large measurement range, high precision, simple and easy installation, maintenance-free operation, and a long service life. It uses probes in various forms of exposed and insulated materials. It is used for measuring viscous, dirty media, granular media, and mixed media in almost all application scenarios, and is particularly suitable for measuring highly corrosive media such as strong acids and bases. Radio frequency admittance is a level measurement technique that evolved from capacitive methods; it is more reliable, accurate, and versatile for preventing material buildup. In the context of radio frequency admittance, admittance refers to the reciprocal of impedance, and it is a signal resulting from the combination of resistance and capacitance. Since radio frequency denotes high-frequency radio waves, radio frequency admittance can be understood as the measurement of admittance using high-frequency radio waves. Principle of the radio frequency admittance level gauge: The key difference between radio frequency admittance technology and capacitance technology is that it uses a demodulator circuit to address the issue of residue buildup. Additionally, three-terminal technology is employed; the connection between the electronic unit and the probe is made using a special coaxial three-terminal cable. The central wire of this cable is used to transmit the changes in capacitance from the probe to the electronic unit, while the coaxial shielding wire transmits the shielding voltage (admittance) signal. The purpose of shielding is to eliminate the capacitance between the central wire and ground. The ground wire is another separate conductor in the cable. Therefore, the cable capacitance does not affect the capacitive signal from the probe, and it is thus not necessary to \"zero\" the cable capacitance of the electronic unit in order to obtain accurate readings. Shielding can also prevent output errors caused by changes in capacitance resulting from temperature variations in the cable. To address the issue of material sticking to the probe, a new probe structure with a five-layer concentric design is employed: the innermost layer is the central measuring rod, the middle layer is the COTE-SHIELD shielding layer, and the outermost layer consists of grounded mounting threads, all of which are separated from one another by insulating materials. Since there is no potential difference between the measuring rod and the shielding layer, no current will flow even if the impedance of the material attached to the sensing element is very low. The electronic instrument measures only the current from the center of the probe to the tank wall, thereby protecting the measurement terminal from being affected by the attached material. Only when the liquid level in the container actually rises and comes into contact with the central probe does a current flow between the material being measured, the central probe, and the ground. After completion of calibration, radio frequency admittance level gauges generally require no maintenance. Occasionally, abnormal fluctuations or fixed readings may occur during operation; this is usually due to a problem with the probe. Therefore, when checking such gauges, first verify that the power supply is functioning properly and stably. Then disconnect the probe cable from the electronic unit and measure the resistance between the center of the probe and ground – it should be above 2M ohms under normal conditions. If the resistance is below 2M ohms, it indicates that there is a leakage in the probe, meaning the probe has been damaged as a result of external forces, and in such cases the probe must be replaced.