Radio frequency RF admittance is a new type of level control technology with wider applicability developed from capacitive type. It is an upgrade of capacitive level technology. The so-called radio frequency admittance, the meaning of admittance is the reciprocal of impedance in electricity. It is composed of resistive components, capacitive components, and inductive components. The radio frequency is the high-frequency radio spectrum. So the radio frequency admittance can be understood as using high frequency Radio wave measurement admittance.
When the meter is working, the sensor of the meter forms an admittance value with the tank wall and the measured medium. When the level changes, the admittance value changes accordingly. The circuit unit converts the measured admittance value into a level signal output to realize level measurement.
RF admittance level switch working principle
The RF admittance level controller 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 so-called radio frequency admittance means the inverse of the impedance in electricity. It is composed of resistive components, capacitive components, and inductive components, and radio frequency is the high-frequency radio spectrum. Therefore, radio frequency admittance can be understood as the use of high frequency. Radio waves measure admittance. When the meter is working, the sensor of the meter forms an admittance value with the filling wall and the measured medium. When the material level changes, the admittance value changes accordingly, and the circuit unit converts the measured admittance value into a level signal output to realize the level measurement.
What is the RF admittance level switch sensor sensitivity ?
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
How to adjust the RF admittance level switch sensor sensitivity ?
Potentiometer W1 is a sensitivity adjustment potentiometer: the LED two-color display light is green when there is no material, and the red light is on when there is material. instrument
After the meter is powered on, the green light will be on when the material level is lower than the set value. At this time, slowly adjust the potentiometer W1 clockwise until the red light is on, and then adjust it counterclockwise 3 turns (0.5 to 3 turns for non-conductive materials, 5 turns for conductive materials). ~7 circles) and the green light is on (with the change of the traffic light display state, the contact state of the output relay should also change accordingly). It should be covered by the material according to the measuring part of different media sensors should be about 75mm.
RF Admittance Level switch Sensor’s Applications
The RF admittance level switch meter is a general-purpose level meter for continuous level measurement. The product is used in industrial and mining sites and is suitable for most applications. The instrument consists of a circuit unit, a set of explosion-proof housing and rod or cable sensing. Components, sensors are available in a variety of models, the instrument can be installed as a whole or separately.
The principle of RF admittance level meter determines its function and scope of application. The radio frequency admittance level meter is widely used, and several typical occasions are as follows: chemicals, plastics, films; feed, grains, rubber, medicines; liquids, waste water, sand; food, mud, cement; powders, coatings, clothing, Coal; granular solids, oil, pulp.
How to install the RF admittance switch sensor?
The installation position of the sensing element (probe) is usually determined by the position of the opening of the container, but it should not be installed in the feed stream. When there is no suitable position inside the container, consider using the outside arm or graduated cylinder installation.
When the sensor is installed on the side wall, the protective electrode should enter the container and hang through the side wall, so please pay attention to the length of the protective electrode when selecting the type.
In order to make the device work properly and accurately, please install it according to the following steps:
A. In the case of insulating sensors, the installation must be very careful, because in this case, it is possible to damage the insulation of the probe, especially the thin capacitive probe.
B. The sensing element should not be installed so that it is in the direct flow of material from the filling nozzle or tank. If this is not possible, add a baffle between the probe and the fill.
C. Do not disassemble the sensor or loosen the mounting seal.
D. Tighten the sensing element with the flat part of the wrench.
E. The shielding layer must pass through the tank wall when the probe is installed.
Notice:
Do not use one-component ambient vulcanized sealants for probes or instrument enclosures, which often contain acetic acid, which will corrode circuit components. A special two-component sealant (non-corrosive) should be used, please consult the manufacturer on which two-component sealant to use.
※Note: As one of the earlier Capacitive Level measurement manufacturer, SenTec provide A wide variety ofRF Admittance Level switch Sensor for tank level measurement solutions.
For specific RF Admittance Level switch Sensor price, please contact our sales engineer.
