Introduction
Ultrasonic level meter working principle is sent out by the ultrasonic transducer (probe) high-frequency pulse sound waves encountered by the measured level (material) surface is reflected back reflected echo is received by the transducer into an electrical signal. The propagation time of the sound wave is proportional to the distance from the sound wave to the surface of the object. Sound wave transmission distance S with the speed of sound C and sound transmission time T relationship can be expressed in the formula: S = C × T / 2. Temperature compensation formula for sound speed: ambient sound speed = 331.5 + 0.6 × temperature.
Because the emitted ultrasonic pulse has a certain width, the reflected wave and the emitted wave in a small area close to the transducer overlap and cannot be identified, and the distance value cannot be measured. This area is called the measurement blind area. The size of the blind zone is related to the type of ultrasonic level meter.
The most used ultrasonic sensors are transducers made of piezoelectric wafers or piezoelectric ceramics. The reception and reflection of ultrasonic waves are based on the piezoelectric and inverse piezoelectric effects of the piezoelectric chip. Its working principle: when the piezoelectric chip is excited by the emission pulse to produce vibration, can be emitted acoustic pulse, this is the inverse piezoelectric effect.
When ultrasonic waves are applied to the wafer, the deformation caused by the forced vibration of the wafer can be converted into a corresponding electrical signal, which is the positive piezoelectric effect. The former is the emission of ultrasonic waves, and the latter is the reception of ultrasonic waves. The same piezoelectric crystal is responsible for both the transmission and reception of ultrasonic waves. Therefore, between the transmitting and receiving states, it takes a period of time for the piezoelectric crystal to return from the oscillating state to the stationary state before it can start receiving the reflected ultrasonic signals.
In the blind zone, the u
ltrasonic water tank level meter can not be measured. Generally, the larger the measuring range of the ultrasonic level meter, the larger the blind zone. Different ultrasonic frequencies are used for different ranges of ultrasonic level meters. The general rule is that the smaller the range, the higher the ultrasonic frequency, and the larger the range, the lower the ultrasonic frequency. This is because the ultrasonic energy is attenuated in the medium through which it is emitted and returned, and the energy of the low frequency long wave is larger, which can ensure that the ultrasonic energy is not attenuated too much in the long time propagation process.
Specification
| Product |
Ultrasonic Water Tank Level Meter |
| Model |
SUP-ULS-B |
| Measure Range |
0-5m, 0-10m, 0-15m(optional) |
| Blind Zone |
≤0.3m(5m)
≤0.35m(10m)
≤0.5m(15m) |
| Accuracy |
±0.5%FS |
| Display |
Monochrome LCD screen |
| Output (Optional) |
Isolated, 4-20mA |
| Output precision:±0.5%FS |
| RL≤500Ω |
| Measuring Variable |
Level/Distance |
| Power Supply |
100-240 VAC, 5W MAX, 50/6Hz
18-28 VDC |
| Temperature Range |
Converter: -20-60 ℃
Sensor: -20-80 ℃ |
| Huminity Range |
10%-85% RH (no condensation) |
| Ingress Protection |
Converter: IP65
Sensor: IP68 |
| Cable |
10m (Standard)
30mMAX (optional) |
| Alarm |
2 relays
Capacitance AC250V/3A (Standard)
4 relays (optional) |
| Inatallation |
Wall-mounted |
| Communication |
Isolated RS485, Modbus-RTU |
Application
