Xylem H-312-22 - Manual (Page 24)

4-4 SDI-12 Command and Response Protocol H-312
4.3 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
"aD0!" through "aD9!" "apd.d ... pd.d<cr><lf>"
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 (<CR><LF> only), it means
that the measurement was aborted and a new "M" command must be sent.
Example of a H-312 "aD0!" command:
Previous Command
Response
"aM!" "a0034<cr><lf>"
Subsequent Command Response
"aD0" a+AA.AAA+BB.BBB+CC.C+DD.D<cr><lf>
Where:
AA.AAA = Stage (feet, inches, meters etc.)
BB.BBB = Pressure (PSI)
CC.C = Temperature (C)
DD.D = Sensor Supply Voltage (Volts)