DLM-551 ultrasonic level gauge(transmitter) is a digital level meter controlled by a microprocessor.
In the measurement, the ultrasonic pulse is emitted by the sensor (transducer), and the sound wave is reflected by the liquid surface and then received by the same sensor or ultrasonic receiver, converted into an electrical signal by the piezoelectric crystal or magnetostrictive device, and transmitted and received by the sound wave. The time between the time to calculate the distance from the sensor to the surface of the liquid being measured. Due to the non-contact measurement, the measured medium is almost unlimited and can be widely used for the measurement of various liquid and solid materials.
The ultrasonic level gauge consists of three parts: an ultrasonic transducer, a processing unit, and an output unit.
The ultrasonic level gauge can adopt two-wire system, three-wire system or four-wire system technology. The two-wire system is: power supply and signal output sharing; three-wire system is: power supply loop and signal output loop are independent. When DC 24v power supply is used, one can be used. 3-core cable, the negative terminal of the power supply and the negative terminal of the signal output share a core wire; the four-wire system is: when the AC 220V power supply is used, or when the DC 24V power supply is used, the power supply circuit and the signal output circuit are completely isolated. Use a 4-conductor cable. DC or AC power supply, with 4~20mADC, high and low level switching output.
Range: 0-50 meters, a variety of forms are available, suitable for a variety of corrosive, chemical applications, high precision, remote signal output, PLC system monitoring.
The working principle of the ultrasonic level meter is that the ultrasonic transducer (probe) emits high-frequency pulse sound waves. The surface of the measured object (material) is reflected and folded back. The reflected echo is received by the transducer and converted into an electrical signal. The propagation time of the sound wave It is proportional to the distance from the sound wave to the surface of the object. The relationship between the acoustic wave transmission distance S and the sound velocity C and the acoustic transmission time T can be expressed by the formula: S=C×T/2.
Since the transmitted ultrasonic pulse has a certain width, the reflected wave and the transmitted wave in a small region closer to the transducer overlap, and cannot be recognized, and the distance value cannot be measured. This area is called the measurement dead zone. The size of the blind spot is related to the model of the ultrasonic level gauge.
The probe part emits ultrasonic waves, which are then reflected by the liquid surface, and the probe part is received again. The distance from the probe to the liquid surface is proportional to the time the ultrasonic wave passes:
Distance [m] = time × sound speed / 2 [m]
Temperature compensation formula for sound velocity: ambient sound velocity = 331.5 + 0.6 × temperature
Automatic power adjustment, gain control, temperature compensation.
Advanced detection technology and rich software functions adapt to various complex environments.
The new waveform calculation technology is adopted to improve the measurement accuracy of the instrument.
The suppression function with interference echo ensures the authenticity of the measured data.
A variety of output forms: programmable relay output, high precision 4-20mA current output, Rs-485 digital communication output split ultrasonic level probe.
When the ultrasonic level gauge is working, the high-frequency pulse sound wave is emitted by the transducer (probe), and the surface of the measured object (water surface) is reflected, and the reflected echo returned by the same transducer is received by the same transducer (probe) and converted into an electrical signal. . The time between the transmission and reception of the pulse (the motion time of the sound wave) is proportional to the distance from the transducer to the surface of the object. The relationship between the distance S of the sound wave transmission and the speed of sound C and the transmission time T can be expressed by formula: S = CXT /2
The installation of the ultrasonic level timer must take into account the blind spot problem of the ultrasonic level gauge. When the liquid level enters the blind zone, the ultrasonic transmitter cannot measure the liquid level, so when determining the range of the ultrasonic level gauge, a margin of 50 cm must be set. When installing, the transmitter probe must be higher than the highest liquid. The position is about 50 cm. This will ensure accurate monitoring of the liquid level and ensure the safety of the ultrasonic level gauge.
In actual use, the level gauge is flooded by water due to poor consideration during installation, resulting in complete damage to the level gauge.
Low price, small size, light weight, can be used in food, chemical, semiconductor and other industries for liquid and bulk solids non-contact level measurement, can be used for remote level monitoring and pump control.
When installing mechanically, it should be noted that the installation should be perpendicular to the surface of the object, avoiding the use of objects for measuring foam properties, and avoiding the distance from the surface of the measuring object to be less than the blind zone distance (blind zone: there will be one standard for each product, known with the product) Should consider the bundle to avoid the barrier material does not meet the nozzle and the container wall, the detection of large solid objects should adjust the probe orientation, reduce measurement error.