Xi'an Huance Automation Technology Co., Ltd. |
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GML801-A 1.8GHz 4-20mA liquid, solid powder bunker fuel ammonia tank reservoir guided wave radar level transmitter
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. 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
●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.
●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.
●Using pulse working mode, the product has extremely low emission
power, and can be installed in various metal and non-metal
containers without harming the 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 Way
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, reservoirs, exhaust
gas purification tanks, silo pumps, steam drums, ash storage, fuel
tanks, etc.;
Oil field:crude oil storage tank, refined oil storage tank, three-phase
separator, settling tank, sewage tank, oil-water interface,
drilling mud tank, etc.;
Chemical industry: crude oil distillation tower, raw material warehouse, intermediate
silo, reaction tank, ammonia water tank, solid silo, separator,
asphalt storage tank, etc.;
Metallurgy: blast furnace, ore silo, ore crusher, raw material warehouse,
auxiliary material warehouse, alumina powder warehouse,
electrolytic tank buffer tank, etc.;
Cement: stone silos, raw silos, cement silos, coal powder silos, slag
storage silos, commercial warehouses, etc.;
Food: juice factory, milk factory, raw sugar storage tank, ketchup
storage tank, brewery storage tank, etc.;
Pharmaceutical: Chinese medicine storage tanks, separators, fermenters, etc.;
Water treatment: reservoir, sewage pool, water treatment tank, sedimentation tank,
deep well, drinking water network, etc.;
Papermaking: raw material warehouse, storage tower, drying drum, chemical
material storage warehouse, etc.;
Other: quarry, coal mine, environmental protection, shipbuilding, and
other industries.