Hello @Bonnie ,
Have you done the calibration both empty and full?
Is the sensor placed at the recommended distance from any obstacle?
Have you performed interference echo suppression?
There might also be linearization.
Take a look at this—I hope it helps.
In the manual on page 21:2.1.3 “LVL N empty calibration" (N = 1 or 2) This function allows you to input the E “empty” distance, i.e. the distance between the reference point of the sensor and the minimum level (zero point).
2.1.4 "LVL N full calibration" (N = 1 or 2) This allows you to input the level F, i.e., the distance between the minimum and maximum levels.
You can get the manual here:
The explanations are clear.
There is also a video.
On page 27, section 2.1.7, you’ll find the basic principles for interference echo suppression.
If you are still stuck, E&H customer support is top notch. Just contact the representative in your area.