Framework conditions for a reliable measurement
The installation location can have an impact on the quality of the measurement results. For optimum accuracy, install the LVL-R-5
- at a location with calm water surface
- centrally above the flume
- in distance from structures and fittings such as ladders or struts
- perpendicular to the water surface
- at a min. distance of 30 cm to the water surface.
To ensure that the water level can be determined correctly, a significant proportion of the transmitted radar signal must be reflected. Materials such as concrete, silt or wood can attenuate or scatter the reflection, thereby compromising measurement accuracy. This must be taken into account for channels or basins that dry out partially or completely. Where possible, the level sensor should be installed at the position that remains filled with water for the longest period. A calm water surface is preferable to a turbulent one. A short distance from the water surface also has a positive effect on the strength of the reflected radar signal. However, the sensor must always be mounted above the maximum expected water level. The range of the sensor covers a circular area. The diameter of this detection range is determined by the distance from the water surface and is calculated as follows:
B = 2 x A x tan (4°/2) |
The following table shows the diameter of the detection range (beamwidth) at different mounting heights.
| A [mm] | B [mm] |
|---|---|
| 1000 | 69,8 |
| 1500 | 104,8 |
| 2000 | 139,7 |
| 2500 | 174,6 |
| 3000 | 209,5 |
| 3500 | 244,4 |
| 4000 | 279,4 |
| 4500 | 314,3 |
| 5000 | 349,2 |
When selecting a suitable installation location, the following conditions should also be avoided:
Vibrations: Choose a stable, vibration-free installation site. Vibrations can be caused, for example, by traffic or wind.
Accumulations of foam: Foam can significantly impair measurements due to its uneven, air-filled surface, as the radar signal is both scattered and attenuated .
Flooding: Always install the LVL-R-5 above the maximum expected water level. The blocking distance (0...30 cm) should also be taken into account.
The LVL-R-5 can withstand short-term flooding, but can be damaged by foreign matter in the wastewater. When installed correctly, the Ceiling mount for pipe (400417) offers a certain degree of protection against foreign substances and can be used in channels that are temporarily filled to capacity. However, as long as the LVL-R-5 is flooded or the water level is within the blocking distance (0...30 cm), the measurement will not provide valid values.
Rain: Rain can significantly affect measurements, as raindrops reflect and scatter the radar signal. The reflections from large drops are difficult to distinguish from those on the water surface. In addition, the kinetic energy of the falling drops creates concentric waves that further disturb the water surface.
Obstructive objects: There must not be any obstacles between the LVL-R-5 and the water surface. This applies to the entire space between the sensor and the water surface covered by the radar cone (see figure Detection range of the sensor).
