Operating Instructions

10 Troubleshooting
Sensor not responding to RS-485 interface
!
Sensor correctly connected to a data logger with SDI-12-input (master)?
➝ Correct terminal assignment.
!
Supply voltage polarity reversed?
➝ Correct terminal assignment.
!
Supply voltage < 9 V or > 27 V?
➝ Correct supply voltage level (check length and cross section of
connecting cable).
!
Can the supply voltage used deliver1 A output current?
➝ Use a suitable supply voltage.
!
Is the supply voltage a DC voltage?
➝ Only operate the sensor with DC voltage.
Measured values are incorrect or missing
!
Sensor (front panel, Radom) soiled?
➝ Carefully clean sensor; see Chapter 7, Performing maintenance work.
!
Obstructions inside or in the immediate vicinity of the radar sensor footprint?
➝ Remove obstructions.
!
Sensor tilt angle in permitted range (20° … 60°)?
➝ Correct tilt angle.
!
Distance to measuring point in permitted range (1 … 50 m)?
➝ Optimise installation location.
!
Alignment of sensor not parallel to flow direction?
➝ Optimise alignment.
!
Installation point of sensor not stable (e.g. continuous significant
fluctuations of bridge)?
➝ Optimise installation location.
!
Large metallic surfaces close to the radar sensor footprint (e.g. sheet piling)?
➝ Optimise installation point.
!
Measuring point is not suitable for measurement of the surface flow velocity;
see Chapter 5.1?
➝ Change measuring point.
!
Measured values are explicitly incorrect during precipitation events, with "away
from sensor" alignment?
➝ Change alignment to "towards sensor".
!
In addition for all potential faults:
➝ Check "Signal quality index" and "Vibration index".
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