Campbell CS475, Instruction Manual

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Appendix C. SDI-12 Commands/ Changing Settings
C-4
radar sensor then emits the short microwave pulses. Any echo occurring 0.5 m
(1.6 ft) short of the distance you entered will be considered noise.
To start False Echo Learn , do the
nnn.nnn!
command (where
nnn.nnn = the actual distance to the water) followed by the
aD0!
( Send Data )
command. TABLE C-5 shows an example of the command and response.
TABLE C-5. Example of a Start False Echo Learn Command
Initial Command Response
2.500!
Where (from left to right),
0—sensor’s address;
2.500—the water surface distance.
02001<cr><If>
Where (from left to right),
0—sensor’s address;
200—the amount of time (in
seconds) that you must wait before
sending the send data command;
1—the number of values that will be
placed in the buffer.
Subsequent Command Response
0D0!
Where the first zero is the sensor
address.
This is the send data command.
0+2.500<cr><lf>
Where (from left to right),
0—sensor’s address;
2.500—the water surface distance.
C.1.4 Set Units
The distance measurement can be reported in feet (default) or meters. Change
the units by first using the aXSU+n! command (where n = 1 (feet) or 0
(meters)) followed by the aXGU! (
Get Units
) command. TABLE C-6 shows an
example of the command and response for changing this setting.
TABLE C-6. Example of Setting and Getting Units
Initial Command Response
0XSU+0!
Where the first zero is the sensor
address and the second zero sets the
units to meters.
00011<cr><If>
Where (from left to right),
0—sensor’s address;
001—the amount of time (in
seconds) that you must wait before
sending another command;
1—the number of values that will be
placed in the buffer.
Subsequent Command Response
0D0! 0+0<cr><If>
Where the first and third zero is the
sensor’s address and the fourth zero
indicates the units to meters
0+0<cr><If>
Where the first zero is the sensor
address and the second zero indicates
that the units are now meters.