700-SDI-RADAR-300W-Man Rev 2 30 May 2022
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Part# 21370
4.2.5
SDI-12 PROTOCOL
SDI-12 Protocol is achieved using the SDI-12 Adapter. Instructions to connect the radar to the SDI-12
adapter are contained in the Appendix.
BASIC SDI-12 COMMANDS
The following basic SDI-12 commands are implemented in the radar sensor.
Note the following:
•
The “a” in each command should be replaced with the sensor address number
•
Every command must terminate with an exclamation mark (!)
•
Measurement (M) commands and Concurrent measurement (C) commands are appended
with a C to have the data returned with a cyclic redundancy check (CRC)
•
The CRC is added at the end of the message for commands with CRC
•
The measurement command must be followed by a Send Data command (
aD0!
) to view the
data
Name
Command Response and Details
Address Query
?!
a
Device responds with its SDI-12 address. Default address is 0 (zero )
Acknowledge
Active
a!
a
Sensor at input address “a” is active
Address
Change
aAb!
b
Device at address ”a” has changed address to “b”
Send
Identification
a
I
!
a13GLX2300Wfff
a = SDI-12address
13 = the SDI-12 version 1.3
GLX = vendor identification
2300W = sensor model
fff = firmware version of the SDI-12 adapter
Start
Verification
Send
Verification
Data
aV!
aD0!
a0002
a = SDI-12 address
000 = data is immediately ready (zero seconds until data is ready)
2 = two values are available
Verification values can be retrieved by the Send Data Command
a+d1+d2
a = SDI-12 address
+d1 = adapter status
0 = error; 1 = OK
+d2 = radar status
0 = error; 1 = OK
