ULS Level Sensor


The sensor is used to measure the height of the hydrometric level. The sensor, managed by a microprocessor, bases its operation on an ultrasonic transducer that sends a pulse to the surface whose distance is to be measured, and then reads the resulting reflected echo. To remedy the systematic measurement errors usually occurring in the ultrasonic sensors, it is necessary to take into account the influence that the changes in temperature (and also in the atmospheric pressure and relative humidity to a negligible extent) have on the speed of propagation of the sound in the medium. This value does not
influence the measurement of the hydrometric level in the ULS sensor produced because the changes in speed of propagation of the sound are compensated using an internal air temperature sensor. Value relating to hydrometric zero.

- Compensation device:
The systematic measurement errors due to changes in the in speed of propagation of the sound caused by temperature variations are compensated using an internal air temperature sensor. It is for this reason that the transducer is housed inside a pagoda structure that guarantees its ventilation. The measurement principle of the ultrasonic sensors is based on the analysis of the time elapsing between sending and receiving the ultrasound or on the control of receiving the sent signal. The emitter and receiver are positioned in the same housing.

- Easy maintenance:
The benefits that this ultrasonic hydrometric sensor offers are not limited to precision, but also include simple and quick maintenance due to the engineering of the sensor that simplifies the phases. The only preventive activity consists of controlling the levelling of the sensor and in cleaning the target struck by the sensor. In fact, there must be no obstacles between the emitter of the sensor and the free surface of the water.

- Sturdy and reliable construction:
It makes it an instrument with a long lifetime, which safeguards the customer’s investment. The instrument does not drift due to aging and requires no periodic calibrations.

The sensor is designed to operate outdoors continually. The target beneath the sensor must be kept free of rocks and various obstacles that might invalidate its measurement. The distance from the control unit must not exceed 200 metres. The sensor must be horizontally positioned at a height, as to the lowest level of the waterway, no greater than its full scale. Furthermore, the highest level of the waterway must reach no more than 50-100 cm depending on the full scale of the sensor. Lastly, there has to be an obstacle-free area of a ≥1.75 m radius as to the vertical of the sensor. Once the sensor is calibrated
in order to get a pre-established output compared to a reference level, the sensor requires no particular maintenance work.
Should failures occur, restoring operation of the station takes less than 1 hour, even if the sensor has to be replaced. The sensor is equipped with fast semiconductor electronic devices for protection from electric discharges.


Range of measurement: Various versions, 6 m, 12 m, etc.
Electrical Output: 4-20mA, 0-10V, RS232
Operative temperature: -25°C... +70°C

Monitored Parameters:

  • Water levels
  • Hazards:

  • Land and river flooding
  • ✓ Relevant to the EWSS


    Minimum Quantity : 1


    Sensor Properties
    Accuracy (error of the measurements) Unit of measurement Data Refresh Time (mins) Wi-Fi Connection 4G Connection External Power Supply Documentation
    in the order of mm m None False False True See available docs for ULS Level Sensor
    Reference Partners Project Name Project Year Reference Paper Minimum Purchase Spatial Density
    MBI srl None Not available 1 None
    Purchase operations complexity Assembly/Calibration Operations Complexity Deployment operation Complexity Deployment Cost Data Analysis Operations Complexity
    Easy Neutral Low Easy
    Citizen Science Activities Complexity Assembly Public Involvement Deployment Public Involvement Data analysis Public Involvement Target Users
    Easy Limited Limited Limited

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