Xylem H-340SDI - Manual (Page 18)

2-4 SDI-12 Command and Response Protocol
H-340SDI
The data recorder may wake the sensor with a break and collect the data anytime after the specified
processing time has elapsed.
2.4 Send Data Command
The Send Data command returns sensor data generated as the result of previous "aM!", “aC!” or
"aV!" commands. Values returned will be sent in 33 characters or less. The sensor's data buffer will
not be altered by this command.
Command Response
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"aD0!" through "aD9!" "apd.d ... pd.d"
Where:
a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
D0..D9 are upper-case ASCII characters.
p Is a polarity sign (+ or -)
d.d represents numeric digits before and/or after the decimal. A decimal may be
used in any position in the value after the polarity sign. If a decimal is not
used, it will be assumed to be after the last digit.
For example: +3.29 +23.5 -25.45 +300
If one or more values were specified and a "aD0!" returns no data (a only), it means that
the measurement was aborted and a new "M" command must be sent.