RF Admittance Level Sensor

RF Admittance Level Sensor is developed from radio frequency capacitance. More accurate and more applicable continuous level measurement.

RF Admittance Level Sensor

RF Admittance Level Sensor is a continuous level measurement product designed based on the principle of radio frequency admittance. The product has the advantages of high stability, high sensitivity, and wide range of applications. Compared with the traditional capacitive level sensor, the RF Admittance Level Sensor adopts a modular design. The meaning of admittance is the reciprocal of the impedance in electricity. It is composed of resistive, capacitive and inductive components. The radio frequency is high Frequency radio spectrum. So radio frequency admittance can be understood as measuring admittance with high frequency radio waves. When the instrument is working, the sensor and the tank wall and the measured medium form an admittance value. When the height of the medium changes, the admittance value changes accordingly. The detection circuit converts the measured admittance value into a level signal output.

Sino-Inst offers a variety of  Capacitance Level Transmitters for level measurement. If you have any questions, please contact our sales engineers.

Features of RF Admittance Level Sensor

The radio frequency admittance level meter has the following advantages:

  • Anti-hanging material: unique independent measurement impedance and capacitive reactance design improve the anti-hanging ability
  • Strong adaptability: Probe temperature range: -100 ℃…500 ℃
  • Range: The minimum measurement range can reach a few centimeters and the maximum measurement range can reach hundreds of meters
  • Interface measurement: suitable for measuring oil-water interface and gas-liquid interface
  • Non-sticky: suitable for measuring viscous materials, the probe has no hanging material
  • High stability: stable and reliable output, resistant to fly ash, blanking, moisture, crystallization, waxing
  • Maintenance-free: no movement, no wear parts, no need for frequent cleaning, maintenance, and debugging   
  • Better measurement effect for materials such as powder particles;
  • The process connection size is small, which is convenient for hole installation;
  • It has better adaptability to the measurement of small tanks and special tanks;
  • The measurement blind area is small, which maximizes the measurement range;
  • Good directionality, especially special tanks and special-shaped tanks, with low transmission loss and many measurable media.

RF Admittance Level Sensor Probe Types

RF Admittance Level Sensor-16-Insulated Hard Rod

Probe type: insulated hard rod
Process temperature: -100…200℃
Process pressure: -0.1…4.0MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: corrosive/conductive liquid, viscous liquid, can be installed separately

RF Admittance Level Sensor-17-Insulated Flexible Cable

Probe type: insulated flexible cable
Process temperature: -40…140℃
Process pressure: -0.1…4.0MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: conductive liquid, conductive solid powder, insulated flexible cable, can be installed separately

RF Admittance Level Sensor-18-Non-insulated Flexible Cable

Probe type: non-insulated flexible cable
Process temperature: -100…200℃
Process pressure: -0.1…6.3MPa
Output mode: 4~20mA
Process connection: 1″BSPT thread installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: insulating solid, insulating liquid non-insulated flexible cable, can be installed separately

RF Admittance Level Sensor-19-Insulated flexible cable

Probe type: insulated flexible cable
Process temperature: -100…200℃
Process pressure: -0.1…4.0MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: conductive liquid, interface, can be installed separately

RF Admittance Level Sensor-20-Flexible Cable

Probe type: flexible cable
Process temperature: -50…140°C
Process pressure: -0.1…1.6MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: deep well, super long range, can be installed separately

RF Admittance Level Sensor-21-Hard Rod Tube

Probe type: barrel type hard rod
Process temperature: -100…200℃
Process pressure: -0.1…6.3MPa
Output mode: 4~20mA
Process connection: 1 1/2″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: low dielectric constant liquid, can be installed separately

RF Admittance Level Sensor-22-Double insulated hard rod

Probe type: double rod insulated hard rod
Process temperature: -100…260℃
Process pressure: -0.1…4.0MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: strong corrosive liquid with reference electrode, conductive liquid, interface, can be installed separately

RF Admittance Level Sensor-23-Insulated hard rod

Probe type: insulated hard rod
Process temperature: -100…200℃
Process pressure: -0.1…6.3MPa
Output mode: 4~20mA
Process connection: 1″BSPT thread installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical applications: interface, power off, strong stirring occasions, can be installed separately

RF Admittance Level Sensor-24-High temperature flexible cable

Probe type: insulated flexible cable
Process temperature: -50…800 ℃
Process pressure: -0.1…4.0MPa
Output mode: 4~20mA
Process connection: 3/4″BSPT threaded installation (standard)/flange installation (optional)
Explosion-proof grade: ExiallCT4 (optional)
Typical application: high temperature insulating solid, can be installed separately

Specifications of RF Admittance Level Sensor

Power supply:13VDC~35VDC
Output:4~20mA
Environment temperature:-40℃~70℃
Medium temperature:-100℃~800℃
Linearity:0.50%
Repeatability:0.10%
Delay:1~30s adjustable
Spark protection:built-in spark protection circuit (to sensor)
Electrical interface:M20*1.5
Cable:The special connection cable between the split electronic unit and the sensor is standard 5m, the longest is 50m
Process connection:BSPT threaded installation (standard)/flange installation (optional)
Shell protection:IP66
Certification:ExiaIICT4

Read more about: Factors To Consider When Selecting A Capacitive Level Sensor

RF Admittance Level Sensor’s Applications

  1. Power plants: coal piles, raw coal bins, fuel bins, reservoirs, exhaust gas purification tanks, bin pumps, ash storage, fuel tanks, etc.
  2. Chemical industry: distillation tower, raw material and intermediate silo, reaction tank, ammonia tank, toxic liquid tank, solid silo, separator, etc.
  3. Petrochemical: oil pipelines, distillation towers, concentration tanks, liquefied gas tanks, ammonia tanks, steam drums, oil refinery oil depots, electrical desorption interfaces, asphalt tanks, etc.
  4. Water and water treatment: reservoirs, sewage tanks, water treatment tanks, sedimentation tanks, digestion towers, gas pipelines, deep wells, drinking water networks, etc.
  5. Cement: Stone silos, raw meal silos, cement silos, coal powder silos, slag storage silos, etc.
  6. Metallurgy: ore silo, ore crusher, raw material silo, auxiliary silo, blast furnace, alumina powder silo, electrolytic cell buffer tank, etc.
  7. Oilfield: crude oil or product oil storage tanks, three-phase separators, sedimentation tanks, sewage tanks (pools) and oil-water interfaces, drilling mud tanks, etc.
  8. Papermaking: raw material warehouse, storage tower, drying drum, etc.
  9. Others: quarry, food, pharmaceutical, environmental protection, shipbuilding and other industries

Extended reading: GWR Solid Level Sensor-for Cement silo-Ash powder measure

RF Admittance Level Sensor Working Principle

RF Admittance Level Sensor works based on radio frequency admittance level control technology. Radio frequency admittance level control technology is a development from capacitive level control technology. The material to which the sensor adheres is called hanging material. The anti-hanging material performance is better, the work is more reliable, and the measurement is more accurate. Level control technology with wider applicability. The meaning of “admittance” in “radio frequency admittance” is the reciprocal of impedance in electricity. It is composed of resistive, capacitive and perceptual components. “Radio frequency” means high frequency, so radio frequency admittance technology can be understood as a method of measuring admittance with high frequency current.

The important difference between point radio frequency admittance technology and capacitance technology is the use of three-terminal technology and the diversity of measurement parameters. The measurement signal at the center end of the circuit unit is connected with the center line of the coaxial cable. Then connect to the center end of the sensor.

At the same time, the shielding layer of the coaxial cable is suspended on a level that is very small and very stable, but has the same potential, the same phase and the same frequency as the measurement signal, but has no direct electrical relationship, that is, isolated from each other. The effect is equivalent to that the measured signal passes through a non-inverting amplifier with a gain of “1” and a strong drive capability. The output is connected to the shield of the coaxial cable. Then connect to the shielding layer of the sensor. The ground wire is another independent wire in the cable.

Because of the above-mentioned relationship between the center line of the coaxial cable and the outer shield, there is no potential difference between the two. Therefore, no current flows, that is, no current leaks from the center line. It is equivalent to no capacitance between the two or the capacitance is equal to zero. Therefore, the temperature effect of the cable and the installation of capacitors will not have an impact.

For the problem of hanging material on the sensor. Adopt a new sensor structure, five-layer concentric structure.

Sensor structure: The innermost layer is the center probe, the middle is the shielding layer, and the outermost is the grounded mounting thread, which is isolated by an insulating layer. As with the coaxial cable, there is no potential difference between the center probe and the shield. Even if the impedance of the hanging material on the sensor is small, no current will flow.

The electronic instrument measures only the current from the center of the sensor to the opposite tank wall (ground). Because the shielding layer can prevent the current from flowing back along the sensor to the container wall. Therefore, the ground current can only pass through the measured material to the opposite container wall through the end of the sensor.

That is, U center probe = U shielding layer, I center probe pair shielding layer = (U center probe-U shielding layer) × YL=0.

Although there is a potential difference between the shielding layer and the container wall, current flows between the two. But the current is not measured and does not affect the measurement result. In this way, the measuring terminal is protected from the influence of hanging materials. Only when the material in the container actually opens up and contacts the central probe, the measured current can be formed between the central probe and the ground through the measured material. The instrument detects this current and generates an effective output signal.

Radio frequency admittance technology introduces measurement parameters other than capacitance, especially resistance parameters. The signal-to-noise ratio of the radio frequency admittance level meter measurement signal increases. The resolution, accuracy and reliability of the radio frequency admittance level gauge are greatly improved. The diversity of measurement parameters also greatly expands the reliable application fields of radio frequency admittance level gauges.

The radio frequency admittance level gauge sensor can choose a variety of materials. Can be installed integrally or separately. Used for limit control and alarm. Welcome to contact Sino-Inst for detailed information.

Extended reading: GWR Solid Level Sensor-Cement silo-Ash powder measure

Application Range of Various Level Sensors

There are many types of level gauges. There are heavy hammer level gauges, resistance-rotation level gauges, radio frequency admittance level gauges, diaphragm level gauges, tuning fork level gauges, vibrating rod level gauges.

They each have their own advantages and are suitable for different working conditions.

Rotary resistance level gauge

The anti-rotation level gauge can be used for the measurement of solid particles and dust. Mainly used in feed, silica, stones, spherical particles, wood chips, calcium powder, rubber, metal, limestone, grain, foundry sand, sawdust, coal powder, resin, raw leather, peanuts, clay and other materials measuring.

Radio frequency admittance level gauge

RF admittance level gauge products are widely used. Several typical occasions are as follows: the measurement of materials such as chemicals, plastics, films, feed, grain rubber medicines, liquid waste water, sand, food slurry cement, powder coating/clothing coal, granular solid oil and paper pulp.

Diaphragm level gauge

The diaphragm level gauge can be installed outside the container, whether it is installation, maintenance, equipment replacement or sensitivity adjustment. In practical applications, it is not recommended to use in the environment where the material is extremely light, viscous or large particles

Tuning fork level gauge

A dual-purpose level switch with an intelligent circuit for the tuning fork level gauge. Suitable for almost all liquids, light, easy-flowing solids

Vibrating rod level gauge

The vibrating rod level gauge can be used to monitor powder, grain or bulk materials (the diameter does not exceed 5-10cm). The density of the material must be greater than 0.05KG/DM3.

If it is lower than this density, the internal friction of the material will not be enough to weaken the amplitude of the vibration switch. This kind of vibrating level switch can be widely used in the monitoring of coal, cement, limestone, grain, sugar, fly powder and other materials.

Featured Level Sensors

Frequently
Asked
Questions

Radio frequency 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 level sensor adopts advanced RF admittance technology. It overcomes the defect that the capacitive level meter cannot eliminate the influence of the conductive hanging material.

It is not affected by water vapor, dust or condensation, and has the advantages of stable and reliable long-term operation, high sensitivity, good linearity, high temperature resistance, and high pressure resistance.

It can be used for liquid level (level) measurement of liquid, oil and solid measurement, without moving parts.

The RF type level switch realizes the level measurement and control by sensing the change of reactance (capacitive reactance and impedance) between it and the tank body.

The internal electronic unit, the reactance between the probe measuring pole and the empty tank together form a balanced bridge circuit and generate a stable oscillating signal.

When the measured medium covers the probe measuring pole, the reactance change between the probe measuring pole and the tank will cause the bridge circuit to be unbalanced and stop generating oscillating signals. The post-stage circuit detects this change and outputs an alarm signal.

The oscillating signal is applied as a radio frequency signal at the same time as the probe’s measuring pole. It is also sent to the protection pole of the probe after passing through a 1:1 voltage follower. The radio frequency signals of the measuring electrode and the protection electrode have the same potential, the same phase, the same frequency and are isolated from each other.

When the probe is hung with material, there is no potential difference between the measuring electrode and the guard electrode to form electrical isolation to ensure that the signal change of the guard electrode does not affect the detection. The change of the reactance on the probe measuring pole can only be determined by the material between the probe measuring pole and the tank. So that the hanging material on the probe will not affect the normal detection.

Types of Level Transmitters:
Level measurement transmitters are of seven types. Each type of transmitter works in a different way, and makes it useful for different types of processes.
Capacitance Level Transmitters
Hydrostatic Level Transmitters
Magnetic Level Transmitters
Radar Fill Level Transmitters
MUltrasonic Level Transmitter
Guided Microwave Level Transmitters
Hydrostatic level transmitters

The main function of the liquid level sensor is to detect the liquid level. The functions that can be implemented include water shortage protection, no water alarm, waterproof overflow, high liquid level reminder, etc.
The liquid level sensor is used to detect the liquid level, and it is determined that the liquid level needs to be controlled at the position. Then the liquid level sensor is installed in the corresponding position.
For example, the liquid level at the bottom of the container needs to be measured, and a signal reminder needs to be given when no liquid is detected.
Then when the container is in a liquid state, the sensor works normally. When the liquid level drops to a low level, the liquid level sensor will give a signal reminder or alarm when it detects this industrial control change.

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Sino-Inst offers over 10 RF Admittance Level Sensors for level measurement. About 50% of these are RF level meters, 40% is the tank level sensor.

A wide variety of RF Admittance Level Sensors are available to you, such as free samples, paid samples.

Sino-Inst is a globally recognized supplier and manufacturer of RF Admittance Level Sensor instrumentation, located in China.

This entry was posted in Capacitive Level, Level Transmitters by KimGuo11. Bookmark the permalink.

About KimGuo11

Wu Peng, born in 1980, is a highly respected and accomplished male engineer with extensive experience in the field of automation. With over 20 years of industry experience, Wu has made significant contributions to both academia and engineering projects. Throughout his career, Wu Peng has participated in numerous national and international engineering projects. Some of his most notable projects include the development of an intelligent control system for oil refineries, the design of a cutting-edge distributed control system for petrochemical plants, and the optimization of control algorithms for natural gas pipelines.