Beam Angle; Programming The In-Pipe Ultrasonic Sensor; Calibrating The In-Pipe Ultrasonic Sensor - Sigma 980 Operating And Maintenance Manual

Section 4
Figure 38 Side View of In-Pipe
A. Minimum distance to reflecting obstruction (2 m (82 in.))
B. Distance from Sensor
(Range: 1.6 cm (0.64 in.) to 4.11 m (13.5 ft))
C. 45° Deflector

4.11.2 Beam Angle

4.11.3 Programming the In-Pipe Ultrasonic Sensor

4.11.4 Calibrating the In-Pipe Ultrasonic Sensor

Page 88
In-Pipe Ultrasonic Sensor
The narrow beam of sound that emanates from the bottom of the in-pipe
ultrasonic sensor spreads out at an angle of ±12° (-10 dB) as it travels away
from the sensor. This means that if the sensor is mounted too high above a
narrow channel, the beam may be too wide when it reaches the bottom of the
channel. This may cause false echoes from the sides on the channel walls.
The in-pipe ultrasonic sensor does not require operator programming, unless
more than one sensor option is connected to the 980 Flow Meter. When more
than one sensor option is connected:
1. From the Main Menu, select
2. Select Ultra-Sonic Sensor using the
the soft key.
ACCEPT
Calibrate the in-pipe sensor each time the sensor is installed at a new site.
Calibrate the in-pipe via one of two methods; Liquid Depth or Sensor Height.
Each method has its own advantages and disadvantages. Liquid Depth
calibration is the recommended calibration method, use the sensor height
method only when Liquid Depth calibration is not an option. An Invisible
Range can also be set which allows the transducer to ignore reflections from
obstructions between the sensor and the water surface, such as ladder rungs,
channel side walls, etc.
1. From the Main Menu, select
D. Ultrasonic Sensor
E. Internal Deadband (18.21 cm (7.17 inches))
OPTIONS > LEVEL SENSOR
CHANGE CHOICE
OPTIONS > ADVANCED OPTIONS.
soft key, then press