9. Diagnostics, repair, and
maintenance
NOTE:
All factory repairs and recalibrations require a returned material authorization (RMA) and
completion of the “Declaration of Hazardous Material and Decontamination” form. Refer to
the
page at the end of this manual for more information.
9.1 Testing procedure
1. Double-check all wiring connections.
CAUTION:
The data logger cannot issue SDI-12 commands when a USB cable is connected to the
sensor.
2. Connect the sensor to your data logger and apply +12 V power.
3. Send the Acknowledge Active command (
a!
). This command is used to check the presence
of the sensor on the bus. Only the address is sent back in response.
4. Send the Identification command (
aI!
).
5. Compare the output stage versus the actual stage using the Start Measurement command
(
aM!
) followed by the Send Data command (
aD!
).
6. Send the Read Configuration Summary command (
aXRCS!
) to retrieve the stored settings
for measurement units, reference stage, calculated offset, power mode, number of
measurements for the average calculation, integration time, and error code. If the sensor is
set up correctly and you are still getting erroneous readings, try completing a False Echo
Suppression to map the sensor to the water surface (
aXFES=xxx.xx!
).
7. Reset the sensor to the defaults (send
aXATZ!
).
9.2 Cyclic redundancy check
The cyclic redundancy check (CRC) is used to produce and send a small, fixed-size checksum of a
larger block of data to the data logger. This checksum detects errors after transmission or
storage. The CRC is computed and added before any transmission or storage. The CRC is also
CS475A Radar Water Level Sensor
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