Hach Ultrasonic flow sensor Manuel D'utilisation page 12

Figure 6 Rectangular weir (without end contractions) dimensions
definitions
1 Sensor
2 Maximum depth
3 Crest height P
12 English
4 Channel width B
5 Crest width B
6 10-inch deadband
Figure 7 Cipolletti weir dimension definitions
1 Sensor
2 Range
3 Depth
4 Maximum depth
Calibrate the sensor
About sensor calibration
The sensor characteristics slowly shift over time and cause the sensor to
lose accuracy. The sensor must be calibrated regularly to maintain
accuracy.
During calibration, data is not sent to the datalog. Thus, the datalog can
have areas where the data is intermittent.
Ultrasonic calibration procedure
Note: If the controller is powered up while the ultrasonic sensor is not plugged in,
the calibration history for ultrasonic flow is deleted.
5 Cipolletti type
6 Taper 4:1 ratio
7 10-inch deadband