Campbell Scientific SR50-L CSC Ultrasonic Distance Sensor - Manual (Page 28)

SR50 Sonic Ranging Sensor
22
Unobstructed Path
22 Deg. 22 Deg.
Perpendicular to Surface
22 Deg.
22 Deg.
FIGURE 7. SR50 Mounting Considerations
5. Data Interpretation
The SR50 makes use of an effective algorithm to help prevent false readings
and to improve the sensor accuracy. Retries and sensitivity adjustments are
also part of the echo detection algorithm. It is important to remember that
under certain circumstances the SR50 may not be able to obtain a reading.
One such example is snow of extremely low density. In this situation, the
surface may not reflect enough sound for the sensor to detect. The SR50 will
output zero for the distance to target or a single pulse in the pulse output mode.
Zero measurements will likely cause problems in processed data output (e.g.,
averages, minimum) of averaging scheme or maximum and minimum outputs.
For this reason one may choose to check whether or not the value being
returned is zero prior to processing and if so, exclude the value with the use of
user Flag 9 (Intermediate processing disable).