In-Situ Aqua TROLL 400 Modbus and SDI-12 Reference Guide - Manual (Page 14)

2.3 Basic Commands
The following table lists each basic SDI-12 command, its format, and the format of each
response.
Name Command Response
Address Query
?! a<CR><LF>
The wildcard address ‘?’ character is supported only for
the Address Query command. It is ignored as an invalid
address for all other commands.
Acknowledge Active
a! a<CR><LF>
Basic address characters in the range ‘0’ to ‘9’ and the
extended address characters in the ranges ‘A’ to ‘Z’
and ‘a’ to ‘z’ are supported. All other characters are
ignored as an invalid address. The default address is
‘0’.
Change Address
aAb! b<CR><LF>
Software changeable addresses and the Change
Address command are supported.
Send Identification
aI! a13IN-SITU AT400 vvv xxxxxxxxxx<CR><LF>
vvv = device firmware version * 100 (120 = 1.20)
xxx = 10-digit device serial number with leading zeroes
Start Verification
Send Data
Additional Data
aV!
aD0!
aD1!…aD9! a0011<CR><LF>
One result is available for reading by the Send Data
command within 1 second. A service request
(a<CR><LF>) will be sent when the result is ready.
a+n<CR><LF>
n = lower 16 bits of the device status (0-65535)
a<CR><LF>
No values are returned after an Additional Data
command.
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