HD2013
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V1.5
5
SDI-12 PROTOCOL
The HD2013…S… rain gauge is equipped with an SDI-12 communication interface
compliant with the version 1.3 of the protocol, which allows the connection to SDI-12
sensor networks.
The communication parameters of the protocol are:
•
Baud Rate = 1200
•
Data bits = 7
•
Parity = Even (E)
•
Stop bits = 1
Communication with the instrument is performed by sending a command in the follow-
ing format:
<Address><Command>!
With <Address> = address of the instrument the command is sent to
<Command> = type of operation requested to the instrument
The instrument reply is as follows:
<Address><Data><CR><LF>
With <Address> = address of the replying instrument
<Data> = information sent by the instrument
<CR> = ASCII character Carriage Return
<LF> = ASCII character Line Feed
The table below shows the available SDI-12 commands. For consistency with the doc-
umentation of the SDI-12 standard, the instrument address is indicated in the table
with the letter a. The rain gauge leaves the factory with address preset to 0. The ad-
dress can be changed by using the proper SDI-12 command reported in the table.
SDI-12 Commands
Command
Instrument reply
Description
a!
a<CR><LF>
Verifies the presence of the
instrument.
aI!
allccccccccmmmmmmvvvssssssss<CR><LF>
with:
a = address of the instrument (1 character)
ll = SDI-12 compliant version (2 characters)
cccccccc = manufacturer (8 characters)
mmmmmm = instrument model (6 characters)
vvv = firmware version (3 characters)
ssssssss = serial number (8 characters)
⇒
Example of response:
013DeltaOhmHD201310013201518
with:
0 = instrument address
13 = SDI-12 version 1.3 compliant
DeltaOhm = manufacturer’s name
HD2013 = instrument model
100 = firmware version 1.0.0
13201518 = serial number
Requests for information
from the instrument.
