LW2120
Electronic level sensor
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7 Operation
7.1 Function check
After power-on and the required parameter setting the unit is in the operating mode. It carries out its
measurement and evaluation functions and generates output signals according to the set parameters.
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Check whether the unit operates correctly.
After power-on (or after sudden changes in distance), the unit first adjusts itself to the level. This
adjustment algorithm requires a certain amount of time and serves to ensure reliable
measurements. After this process, the measured value follows the actual level without delay,
provided that stable measured values are continuously available.
7.1.1 Detection quality check
Using the diagnostic function [Echo peaks], the actual radar echoes of the unit can be viewed
and analysed based on the specified distance and signal strength.
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If necessary, adjust the sensitivity using the [Detection threshold] parameter. Only change
the preset value carefully in small steps. Observe the following instructions.
Turbulence, foam, changes in humidity (e.g. due to increased process temperatures) and steam
can significantly affect the signal strength of the radar echoes.
It is recommended to check the detection quality under real operating conditions; otherwise, the
expected influences should be taken into account when determining the detection threshold,
and the detection quality should be checked later.
Recommendation: Use the factory setting wherever possible, which takes such influences into
account.
7.2 Diagnostic messages, cause, troubleshooting
Diagnostic message
Possible cause
Recommended actions
Device hardware fault.
Electronics error
• Restart the device.
• If the condition persists, replace the
device.
General power supply fault.
Operating voltage drops below 18V dur-
ing start-up.
Verify voltage supply.
Device software fault.
Internal software error
• Restart the device.
• Restore factory settings and
reconfigure the device.
• If the condition persists, replace the
device.
Parameter error
Configuration error
• If an analogue output is used, check
upper and lower range values.
• If a digital output is used, check alert
set points.
• If condition persists, restore default
settings and reconfigure the device.
Short circuit
Short circuit on output OUT1 or OUT2.
Remove the short circuit
Device memory failure
Erroneous data record (e.g. due to a
power failure when writing the data).
• Restore, restart and reconfigure the
device.
• If the condition persists, replace the
device.
