Campbell Scientific CS475, CS476, and CS477 Radar Water Level Sensor - Manual (Page 23)

CS475, CS476, and CS477 Radar Water Level Sensor
7. Installation
Before installing the radar sensor, you must consider all the suggested
guidelines for site and maintenance issues. Do not attempt to install the sensor
unless you are qualified to perform the installation. The sensor is designed for
safe operation in accordance with the current technical, safety, and ANSI
standards.
If you are uncertain of the safe installation and operation of
this unit, read and understand all the instructions included
in this manual before attempting any installation or
operation. CAUTION
7.1 Site Selection
1. Mount the sensor high enough to prevent submersion during flooding
conditions.
Since the sensor is commonly installed over water
from tall structures, use appropriate safety equipment
such as a safety harness or a life preserver when
installing or performing maintenance on the sensor. WARNING
2. Install the sensor above the smoothest part of the water surface.
The smoothest part of the water surface is typically found
halfway between bridge piers. However, bridges with long spans
between the piers experience more vibration. For these bridges,
vibration can be minimized by mounting the sensor a quarter to a
third of the distance to the next pier. NOTE
3. Avoid mounting near horizontal structural surfaces such as beams,
brackets, and sidewall joints because these surfaces reflect a strong signal.
If these structures cannot be avoided, use the False Echo Learn command
to map out the interfering structures in the beam profile (see Appendix
B.1.1, Start False Echo Learn).
4. Center the sensor beam a minimum of 2.5 m from any obstruction in the
measurement range. Obstructions to be aware of include excessive waves,
splashing, pipes, wires, and logs. Note that the radiation beam spreads as
it leaves the sensor (see TABLE 4-2 and TABLE 4-3 in Section 4,
Quickstart).
Usually the beam path is 10° for the CS475, and 8° for the
CS476/CS477. NOTE
5. Be aware that bridges contract and expand with temperature changes.
Traffic loads or trucks can also cause changes to the bridge height.
6. Do not install the sensor where submerged obstructions such as rocks or
bridge piers can distort or disturb water level.
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