RF admittance is a new level control technology developed from capacitive, anti-hanging, more reliable, more accurate and more applicable. It is an upgrade of capacitive level technology. Smart Ceiling Light,Smart Corner Light,Corner Smart Light,Smart Led Corner Lamp Guangdong Smart Street Lighting Co., Ltd , https://www.gdfldlight.com
RF admittance is a new level control technology developed from capacitive, anti-hanging, more reliable, more accurate and more applicable. It is an upgrade of capacitive level technology. The so-called Huajiang RF admittance, the meaning of admittance is the reciprocal of impedance in electricity, which is composed of resistive components, capacitive components, and inductive components. Radio frequency is the high-frequency radio spectrum, so RF admittance can be understood as High frequency radio wave measurement admittance. When the instrument is working, the sensor of the instrument forms an admittance value with the wall and the measured medium. When the level changes, the admittance value changes accordingly. The circuit unit converts the measured admittance value into the level signal output to realize the level measurement.
For continuous measurement, the difference between RF admittance technology and traditional capacitor technology, in addition to the above mentioned, has added two very important circuits, which is based on a very important Huajiang discovery in the practice of conductive hanging materials. of. The above technology also solves the problem of connecting cables at this time, and also solves the problem of vertical mounting of the sensor roots. The two circuits that the lock adds are the oscillator buffer and the AC conversion chopper driver.
For a container with a highly conductive medium to be measured, since the measured medium is electrically conductive, the grounding point can be considered to be on the surface of the probe's insulating layer, which is only a pure capacitor for the transmitter. As the container is discharged, there is a hang on the probe, and the hang material is impedance. In this way, the former pure capacitor has now become a complex impedance composed of a capacitor and a resistor, causing two problems.
The first problem is that the liquid level itself is equivalent to a capacitor for the probe, it does not consume the energy of the transmitter (the pure capacitor does not consume energy). However, if the hanging material has a resistance in the equivalent circuit of the probe, the impedance of the hanging material consumes energy, thereby pulling down the oscillator voltage, causing the bridge output to change and generating measurement errors. We added a buffer amplifier between the oscillator and the bridge to supplement the energy consumed, thus not reducing the oscillating voltage applied to the probe.
The second problem is that for the conductive medium to be tested, the grounding point on the surface of the probe insulation covers the entire measured medium and the hanging area, so that the effective measuring capacitance is extended to the top of the hanging material. This results in a hanging error, and the greater the conductivity, the greater the error. However, any measured medium is not fully conductive. From an electrical point of view, the hanging layer is equivalent to a resistor, and the portion of the sensing element covered by the hanging material is equivalent to a transmission line composed of an infinite number of infinitesimal capacitors and resistive elements. According to mathematical theory, if the material is long enough, the capacitance of the material and the impedance of the resistance part are equal. Therefore, Huajiang added an AC driver circuit based on the error caused by the impedance of the material. The circuit can measure capacitance and resistance separately with an AC converter or a synchronous detector. Since the impedance and the capacitive reactance of the hanging material are equal, the measured total capacitance is equivalent to the C+C hanging material, and the resistance R equal to the C hanging material is subtracted, so that the actual value can be actually measured, thereby eliminating the influence of the hanging material.
Ie C measurement = C + C hanging material
C=C measurement - C hanging material
=C measurement - R
These, multi-parameter measurements are the basis for the implementation of the AC phase detector. Thanks to the use of the above three technologies, RF admittance technology has shown extraordinary vitality in field applications. Huajiang Automation can provide you with the most professional selection suggestions and the most reliable instruments. If you have any questions, we will have professional technicians to help you answer them. I hope to help you!
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RF admittance level gauge instructions