Xylem H-340SDI - Manual (Page 20)

2-6 SDI-12 Command and Response Protocol
H-340SDI
Example of a H-340SDI "aV!" command:
Command Response Time Values Description
------------- --------------------- ------- -------- ---------------------------
"aV!" "a0013" 1 sec 3 Return fixed data and diagnostic
data for testing purposes.
Subsequent Command Response
--------------------------- --------------------------------------------
"aD0" a+123.456+78.9+y
Key Description Units
------------- ------------------------- ----------------------------
+123.456 Fixed test data
+78.9 Fixed test data
y ROM checksum test 0 = Failed, 1 = Passed
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
2.7 Send Acknowledge Command
The Send Acknowledge Command returns a simple status response which includes the address of
the sensor. Any measurement data in the sensor's buffer is not disturbed.
Command Response
------------- -------------------------
"a!" "a"
Where:
a Is the sensor address ("0-9", "A-Z", "a-z", "*", "?").