FTS 21216, Руководство по эксплуатации

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700-SDI-RADAR-LX-80-Man Rev 1 08 Oct 2021 5 /49
Depending on the surface roughness, the incident angle ratio between power reflected away from
the radar and towards the radar can significantly vary.
To maximize reflected power back to the radar, the radar should be mounted so that the angle of
the transmitted radar beam to the water is 90°. In general, the ratio between power reflected to the
sensor and power dispersed in all directions due to surface roughness is very small and it is unlikely
that dispersed energy will cause additional multipath problems due to additional reflections from
surrounding objects.
2.3.6 RELATIVE MEASUREMENT
Each sensor unit measures the distance between the sensor and the first detected object. For water
level measurement, it is preferred to report the actual water level from the bottom of the riverbed
to the surface of the water. That is why we offer relative measurement, which is calculated relative
to the mounted sensor height. Sensor height is defined as the distance from the mounted sensor
position to the bottom of the riverbed. This distance is a fixed value unique to every mounted unit. It
can be set to the device in two ways.
1) First is by setting the sensor height parameter directly using any of communication protocols
described in the following chapters. After setting the sensor height, relative measurement will be
calculated by the following formula:
𝑅𝑅𝑅𝑅
=
𝑆𝑆𝑆𝑆
−
𝐷𝐷
𝑤𝑤ℎ𝑒𝑒𝑒𝑒𝑒𝑒
:
𝑅𝑅𝑅𝑅
=
𝑒𝑒𝑒𝑒𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑟𝑒𝑒 𝑚𝑚𝑒𝑒𝑟𝑟𝑚𝑚𝑚𝑚𝑒𝑒𝑒𝑒𝑚𝑚𝑒𝑒𝑚𝑚𝑟𝑟
𝑆𝑆𝑆𝑆
=
𝑚𝑚𝑒𝑒𝑚𝑚𝑚𝑚𝑠𝑠𝑒𝑒 ℎ𝑒𝑒𝑟𝑟𝑒𝑒ℎ𝑟𝑟
𝐷𝐷
=
𝑚𝑚𝑒𝑒𝑟𝑟𝑚𝑚𝑚𝑚𝑒𝑒𝑒𝑒𝑚𝑚 𝑚𝑚𝑟𝑟𝑚𝑚𝑟𝑟𝑟𝑟𝑚𝑚𝑑𝑑𝑒𝑒 𝑓𝑓𝑒𝑒𝑠𝑠𝑚𝑚 𝑚𝑚𝑒𝑒𝑚𝑚𝑚𝑚𝑠𝑠𝑒𝑒 𝑟𝑟𝑠𝑠 𝑤𝑤𝑟𝑟𝑟𝑟𝑒𝑒𝑒𝑒
.
For example: if the sensor is mounted 6.35m above the riverbed, and the measured distance
from sensor to the surface is 4.34m then the real water level is calculated as the difference
of these two values:
6.35m – 4.34m = 2.01m
In this case the sensor will report 4.34m as the measured level and 2.01m as the measured
relative level.
2) Alternatively, it is possible to set the sensor height indirectly, using the staff gauge
measurement. In this case, the staff gauge measurement needs to be taken directly underneath
the position of the mounted sensor. When setting the sensor height using the staff gauge height,
the following formula will be used to calculate sensor height:
𝑆𝑆𝑆𝑆
=
𝐷𝐷
+
𝑆𝑆𝑆𝑆
𝑤𝑤ℎ𝑒𝑒𝑒𝑒𝑒𝑒
:
𝑆𝑆𝑆𝑆
=
𝑚𝑚𝑒𝑒𝑚𝑚𝑚𝑚𝑠𝑠𝑒𝑒 ℎ𝑒𝑒𝑟𝑟𝑒𝑒ℎ𝑟𝑟
𝐷𝐷
=
𝑚𝑚𝑒𝑒𝑟𝑟𝑚𝑚𝑚𝑚𝑒𝑒𝑒𝑒𝑚𝑚 𝑚𝑚𝑟𝑟𝑚𝑚𝑟𝑟𝑟𝑟𝑚𝑚𝑑𝑑𝑒𝑒 𝑓𝑓𝑒𝑒𝑠𝑠𝑚𝑚 𝑚𝑚𝑒𝑒𝑚𝑚𝑚𝑚𝑠𝑠𝑒𝑒 𝑟𝑟𝑠𝑠 𝑤𝑤𝑟𝑟𝑟𝑟𝑒𝑒𝑒𝑒
𝑆𝑆𝑆𝑆
=
𝑚𝑚𝑟𝑟𝑟𝑟𝑓𝑓𝑓𝑓 𝑒𝑒𝑟𝑟𝑚𝑚𝑒𝑒𝑒𝑒 𝑚𝑚𝑒𝑒𝑟𝑟𝑚𝑚𝑚𝑚𝑒𝑒𝑒𝑒𝑚𝑚𝑒𝑒𝑚𝑚𝑟𝑟
.