Xylem H-340SDI - Manual (Page 23)

H-340SDI
SDI-12 Command and Response Protocol 2-9
Example of a H-340SDI Extended "Read Slope" command:
Command Response Time Values Description
------------------- ------------------------ ------ --------- -----------------------------
"XRS!" "a0011"
1 sec 1 Read Slope
Subsequent Command Response
--------------------------- ------------------------------------
"aD0" a+1.000
This command takes 001 seconds to complete and places 1 value in the data buffer. Use the “aD0"
command to collect and view the data.
2.11 Extended “Write Slope” Command
The H-340SDI processes the raw rainfall values with a “mX” equation. The slope (m) term is
programmable, allowing the user to scale the rain fall value into other engineering units. This
command allows the user to write (change) the current slope term. At the factory the slope is set to
1.000 which provides output data in “inches” of rainfall. The new value is stored in non-volatile
EEPROM within the sensor. Once the new slope value is written to the EEPROM, 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 Slope any other time, use the "Read Slope" command.
Command Response Description
------------- ------------------------- -----------------------------
"aXWSddd!" "a0011" Write Slope
Where:
a is the sensor address ("0-9", "A-Z", "a-z", "*", "?").
XWS are upper case characters.
ddd is the new slope value. The input format is
very flexible. Some examples are shown below.
20.0
0.195
-500
5.93E-4