700-SDI-RADAR-300W-Man Rev 2 30 May 2022
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Part# 21370
MEASUREMENT COMMANDS
The following SDI-12 measurement commands are implemented in the radar sensor. Note the “a” in
each command should be replaced with the sensor address number and every command must
terminate with an exclamation mark (!).
COMMAND(S)
RESULTS
aM! / aMC!
aC! / aCC!
ammm4
ammm04
mmm = number of seconds before measurements will be ready
4 = 4 values will be returned
aD0!
Response: a±f1±f2=d3=d4
a=SDI-12 address
±f1 = average velocity in defined units
±f2 = current velocity in defined units
+d3 = average SNR in dBm
+d4 = instrument tilt angle in degrees
NOTE: Velocity will be negative if the water is flowing away from the sensor
face.
Water flow towards sensor Water flow away from sensor
(positive velocity readings) (negative velocity readings)
X COMMANDS
In addition to the standard set of commands the300W flow meter has an extension of custom
SDI-12 commands called X commands that access specific features of the sensor.
Set commands should normally be followed by a get command to verify the parameter set was
successful
In order for X commands to be valid, the following format conditions must be met:
1)
Replace the “a” with the sensor address
2)
Terminate every command with an exclamation mark (!)
3)
The X and other mandatory characters must be capitalized as shown in the table
4)
Do not place spaces within the command
See Table 4-7 for the most common SDI-12 read/Write commands.
