Doppler flowmeter

1.Product Principle of Doppler Flowmeter

In the field of acoustics, when there is relative movement between the sound source and the receiver (i.e., the probe and the reflector), the frequency of the echo will change. This change in frequency is called a frequency shift, or the Doppler effect. The frequency of sound waves becomes higher as it moves toward the observer and becomes lower as it moves away from the observer. A Doppler flow meter calculates flow velocity by calculating changes in frequency.

2. Technical parameters of Doppler flowmeter

1. Power supply: DC10-15V

2. Working current: 80-180mA 12V

3. Sound wave frequency: 2MHZ

4. Blind zone: 6.5-7 cm (the water level is lower than the blind zone, and the measurement data accuracy is low)

5. Flow velocity range: 0m~+6m/s,

6. Accuracy: ±1.0%±1cm/s

7. Water level: Range: 0.03m~5m (10m can be customized), accuracy: 0.3%±0.5cm

8. Water temperature: Range: -10℃～60℃, accuracy: ±1℃

9. Instantaneous flow range: 0～99.99m³/s

10. Cumulative flow range: 0.1m³～999999m³

3. Doppler flowmeter installation instructions

Normal installation must be 20CM below the lowest water level to avoid exposure to water.

Sensor installation instructions:

4. Precautions for Doppler flowmeter

1. The sensor needs to avoid mud and collision with stones and other objects. In areas with a lot of aquatic plants, grilles need to be installed to avoid entanglement of aquatic plants.

2. Sensor installation direction, the sensor emission surface needs to be installed in the direction of the flow.

3. The sensor has an acoustic blind zone. Try to ensure that the sensor is below 20 centimeters underwater (if the sensor is half-exposed underwater or blocked by sludge, false data may appear. The probability is very low. Usually the data will appear in large numbers, such as more than 2 meters/second. , it is recommended that secondary developers using sensors can block large flow velocity values based on the water level, or in actual applications where the water flow rate is not that large, they can directly block flow rates greater than 2 meters).

4. The cable vent pipe is not difficult to break and affects the water level measurement.

5. Try to do a good job in signal and power lightning protection.

6. If the sensor cable is long, you need to add a 485 relay to avoid interference from the frequency converter.