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Section 4
Page 85
Downlook Ultrasonic Sensor
Note: Always re-check the
Level Adjust when re-installing the
flow meter.
1. From the Main Menu, select OPTIONS>ADVANCED
OPTIONS>CALIBRATION>ULTRASONIC SENSOR.
2. Select Calibrate U-Sonic using the up and down arrow soft keys. Press
the
SELECT soft key.
3. Select Standard as the type of Ultrasonic Transducer using the
CHANGE
CHOICE
soft key. Press the ACCEPT soft key to continue.
Temperature Time Constant
The speed of sound in air varies with the temperature of the air. The ultrasonic
sensor is equipped with temperature compensation to help eliminate the
effect of temperature variation under normal site conditions. The transducer
must be equal to the ambient air temperature at the site prior to calibration for
optimum results. The manufacturer also recommends that sensors be
shielded from direct sunlight for this reason.
4. Enter the ambient air temperature at the transducer location. For optimum
results, allow enough time (100 minutes) to ensure that the sensor is at
equilibrium with the surrounding ambient temperature. Press the
ACCEPT
soft key to continue.
5. Select the Liquid Depth method and enter the new level.
6. Take a physical measurement of the liquid depth (head) and enter
the value.
7. Press the
ACCEPT soft key when finished.
4.10.4.2 Sensor Height
This method requires you to enter the distance between the face of the
ultrasonic sensor and the zero flow point in the primary device. The zero flow
point in a primary device is the level at which flow ceases. In a round pipe the
zero flow point would typically be the invert or bottom of the pipe. In a V-notch
weir the zero flow point occurs when the liquid behind the weir is level with the
bottom of the ‘V’. (There would still be liquid behind the weir plate but it would
not be contributing to flow). Sensor Height calibration is generally used when:
• Access to the primary device is difficult (such as confined space entry in a
manhole) or
• There is no liquid flowing during installation of the flow meter
1. From the Main Menu, select
OPTIONS>ADVANCED
OPTIONS>CALIBRATION>ULTRASONIC SENSOR.
2. Select Calibrate U-Sonic using the up and down arrow soft keys. Press
the
SELECT soft key.
3. Select Standard as the type of Ultrasonic Transducer using the
CHANGE
CHOICE
soft key. Press the ACCEPT soft key to continue.
The speed of sound in air varies with the temperature of the air. The
ultrasonic sensor is equipped with temperature compensation to help
eliminate the effect of temperature variation under normal site conditions.