authenticated by the recipient, after the transmission, to confirm that no alterations occurred.
CRCs are good at identifying errors caused by noise in transmission channels. See
39) for measurement commands with CRC.
9.3 Diagnostics
The radar sensor is extremely reliable, but problems can occur during operation. When you
encounter a problem with the radar sensor, check the error messages to help evaluate the issue
(p. 42)). The error code is part of the data stream when using a measurement command
(
aM!
,
aMC!
,
aC!
,
aCC!
,
aM1!
,
aMC1!
,
aC1!
,
aCC1!
).
NOTE:
During the initial power up or resumption of supply voltage to the sensor, some SDI-12
commands, such as the
I
command, will not yield the expected responses.
Table 9-1: CS475A error codes
Error
code
Description
User action
0
No Error
None
1
Timeout during
data
communication
Sometimes this resolves itself without any action by the user. If it doesn't
resolve itself, try restarting the system. If problem persists, contact
technical support.
2
Internal
Communication
Error
Often this error flag is triggered due to one packet that wasn't
transmitted correctly, so the issue normally resolves itself. If it doesn't
resolve itself, try restarting the system. If problem persists, contact
technical support.
4
Invalid Units
The command that was sent didn't have a valid unit indicator. Send the
command again with a valid unit indicator.
8
Invalid Range
The value sent with the command was outside of the valid range for that
value. Send the command again with a valid value.
16
Communication
Error
There was an error on the communication line. Check all of the
connections to make sure they are correct. Restart the system. If the
problem persists, contact technical support.
9.4 Maintenance
The CS475A is maintenance free under normal operation.
CS475A Radar Water Level Sensor
42
