Working Principle

High-frequency microwave pulse emitted by the guided wave radar propagates along the detecting component (wire cable or steel bar) and encounters the measured medium. Due to the sudden change of the dielectric constant, it causes reflection and a part of the pulse energy is reflected back. The time interval between the transmitted pulse and the reflected pulse is proportional to the distance of the measured medium.

Input

Guided wave radar is a measuring instrument based on the principle of time and travel. The radar wave runs at the speed of light, and the running time can be converted into a level signal by electronic components. The probe emits high frequency pulses and propagates along the cable or rod probe. When the pulse encounters the surface of the material, it is reflected back and received by the receiver in the meter, and the distance signal is converted into a level signal. The reflected pulse signal is transmitted along the cable or rod probe to the instrument electronics portion, and the microprocessor processes the signal to identify the echoes generated by the microwave pulses on the surface of the material.
The correct echo signal identification is done by the pulse software, and the distance D from the surface of the material is proportional to the time travel T of the pulse:
D=CxT/2, where C is the speed of light
Since the distance E of the empty can is known, the level L is: L=E-D

Output

By entering the empty tank height E (= zero point), full tank height F (= full scale) and some application parameters to set, the application parameters will automatically adapt the meter to the measurement environment, corresponding to the 4-20mA output.

 

Design Features

1.Guided wave radar level meter uses advanced microwave processing technology and unique Echo Di scovery echo processing technology, contact measurement, high measurement accuracy and more accurate measurement. At the same time, guided wave radar is anti-adhesive, and is not affected by the external environment such as medium temperature and adhesion.
2.A variety of process connection methods and types of detection components make the 70X series guided wave radar level gauges suitable for a variety of complex conditions and applications. Such as: high temperature, high pressure and small dielectric constant medium.
3.Using pulse working mode, the product has extremely low emission power, and can be installed in various metal and non-metal containers without harming human body and the environment.

Technical parameters

Applicable medium	Liquid,solid,powder
Range	0~30m
Frequency	500MHz~1.8GHz
Antenna	Flexible cable/304/PTFE
Precision	±1mm
Process temperature	-40℃~+130℃ -40℃~250℃
Process pressure	-0.1MPa~4.0MPa
Output	4~20mA/HART/RS-485 Modbus
Power supply	24VDC
Process connection	Thread / flange (optional)
Explosion-proof grade	ExdiaIICT6Gb

Dimensions

Electrical Connections

 

Power Supply

 

4~20 mA/HART (two-wire system):

Power supply and output current signals share a two-core shielded cable. See the technical data for the specific supply voltage range. For intrinsically safe type, a safety barrier must be added between the power supply and the meter.

4~20 mA/HART (four-wire system):

Power supply and the current signal are separated, and each uses a one-core two-core shielded wire. See the technical data for the specific supply voltage.

RS485/Modbus:

Power supply and Modbus signals are separated, and each uses a two-core shielded cable. See the technical data for the specific supply voltage range.

 

Connection Mode

 

Explosion-proof Connection

 

Explosion-proof version of this product is intrinsically safe. Explosion-proof mark: Exia IIC T6. The intrinsically safe guided wave radar level gauge is made of die-cast aluminum housing material, and the electronic components are sealed to ensure that sparks generated during partial circuit failure will not be released. This product is suitable for continuous measurement of the level of flammable medium below the Exia IIC T6 explosion-proof grade.
This product must be powered by a safety barrier. FBS-2 safety barrier is the associated equipment of this product, and the explosion-proof form is intrinsically safe. Explosion-proof mark: [Exia] IIC, supply voltage (21. 6~26.4) V DC, short-circuit current is 135mA, working current (4~20) mA.
Shielded cables are required for all cables, with a maximum length of 500m from the meter to the barrier. The distributed capacitance is ≤0.1uF/km and the distributed inductance is ≤1mH/km. The meter must be connected to the earth when it is installed. Do not use other associated equipment that has not been tested for explosion protection.

 

Installation Requirements

1.It is recommended to install at 1/4 or 1/6 of the diameter of the container. Note: The minimum distance from the tank wall is L0≥300mm, H0≥30mm.
2.Keep away from the inlet and outlet.
3.Keep away from obstacles such as limit switches, heating coils, and agitators. Note: The probe is ≥200mm away from obstacles.
4.When the container is a metal can, the radar should not touch the tank wall and the bottom of the tank over the entire range.
5.If the bottom of the container is tapered, the radar can be mounted in the center of the tank top.
The height of the installation short pipe should be L1 ≤ 10cm.

 

 

Application

Power plants: coal piles, raw coal bunkers, fuel bunkers, cisterns, exhaust gas purification tanks, bunker pumps, steam drums, ash depots, fuel tanks, etc .;
Oil field: crude oil storage tank, refined oil storage tank, three-phase separator, sedimentation tank, sewage tank, oil-water interface, drilling mud tank, etc .;
Chemical industry: crude oil distillation tower, raw material silo, intermediate silo, reaction tank, ammonia water tank, solid silo, separator, asphalt storage tank, etc .;
Metallurgy: blast furnace, ore silo, ore crusher, raw material silo, auxiliary silo, alumina powder silo, electrolytic tank buffer tank, etc .;
Water conservancy: canals, reservoirs, farmland irrigation, river water level monitoring, flash flood warning, urban waterlogging, etc .;
Cement: stone silo, raw silo, cement silo, pulverized coal silo, slag storage silo, commercial boiler, etc .;
Food: Juice factory, milk factory, raw sugar storage tank, tomato sauce storage tank, brewery storage tank, etc .;
Pharmaceutical: Chinese medicine storage tanks, separators, fermentation tanks, etc .;
Water treatment: reservoirs, sewage tanks, water treatment tanks, sedimentation tanks, deep wells, drinking water networks, etc .;
Papermaking: raw material warehouse, storage tower, drying drum, chemical material storage warehouse, etc .;
Others: quarry, coal mine, environmental protection, shipbuilding and other industries.