Xylem H-340SDI - Manual (Page 25)

H-340SDI
SDI-12 Command and Response Protocol 2-11
Example of a H-340SDI Extended "Read Offset" command:
Command Response Time Values Description
------------------- ------------------------ ------ --------- -----------------------------
"XRO!" "a0011" 1 sec 1 Read Offset
Subsequent Command Response
--------------------------- ------------------------------------
"aD0" a+0.000
2.13 Extended “Write Offset” Command
The H-340SDI maintains an offset value in RAM which is automatically added to the Total
Accumulation value. The offset value can be used to match the H340's Total Accumulation to the
current water year rainfall. This command allows the user to write (change) the current offset. The
offset is automatically set to zero at power-up or with the “aXRA” command. To change the Total
Accumulation to a new value you must first reset the accumulators with the “aXRA” command,
then set the offset with the “aXWO” command.
The new value is stored in RAM within the sensor and is not preserved if the power is lost. Once
the new offset value is written to the RAM, a copy is sent to the sensor data buffer for verification.
This data can be viewed by using a subsequent "D" command. To verify the Offset any other time,
use the "Read Offset" command.
Command Response Description
------------- ------------------------- -----------------------------
"aXWOddd!" "a0011" Write Offset
Where:
a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
XWO are upper case characters.
ddd is the new offset value. The input format is
very flexible. Some examples are shown below.
20.0
0.195
-500
5.93E-4