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SDI-12 COMMAND &
RESPONSE PROTOCOL
Initiate Verify Command
The "Verify" command causes a verify sequence to be performed. The result of this command is
similar to the "aM!" command except that the values generated are fixed test data and the results
of diagnostic checksum tests. The data generated in response to this command is placed in the
sensor's buffer for subsequent collection using "D" commands. The data will be retained in the
sensor until another "M", "C" or "V" command is executed.
Command
"aV!"
Where:
a
is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
V
is an upper-case ASCII character.
ttt
is a three digit integer (000-999) specifying the maximum time, in seconds, the sensor
will take to complete the command and have data available in its buffer.
n
is a single digit integer (0-9) specifying the number of values that will be placed in the
data buffer. If "n" is zero (0), no data will be available using subsequent "D" commands
Example of an "aV!" command:
Command
Response
"aV!"
"a0013<cr><lf>"
Subsequent Command
"aD0"
Key
Description
+123.456
Fixed test data
+78.9
Fixed test data
y
ROM checksum test
Send Identification Command
The "Send Identification" command responds with sensor vendor, model, and version data. Any
measurement data in the sensor's buffer is not disturbed.
16
Response
"atttn<cr><lf>"
Time
1 sec
Response
a+123.456+78.9+y<cr><lf>
Units
0 = Failed, 1 = Passed
Description
Initiate verify sequence
Values
Description
3
Return fixed data and diagnostic
data for testing purposes.
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