User manual

Appendix B. SDI-12 Commands/Changing Settings
B-3
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 aXSFEL+nnn.nnn! command (where nnn.nnn =
the actual distance to the water) followed by the aD0! (Send Data) command.
Table 4-5 in Section 4, Quickstart, shows an example of the command and
response.
B.1.2 Set Water Stage
With the Set Water Stage command, you enter the initial depth of the water, and the
sensor will automatically measure the distance between the sensor and the water
surface. The water stage setting and the initial distance measurement are used to
calculate subsequent water stage measurements. Correct stage measurements
require that the water stage setting be in the same units as the Units of Measure
setting. You can find out if the sensor is set to metres or feet by using the aXGU!
(Get Unit) command.
To set the water stage, do an aXSS+nnn.nnn! command (where nnn.nnn = the
initial water depth) followed by the aD0! (Send Data) command. Table 4-6 in
Section 4, Quickstart, shows an example of the command and response for entering
this setting.
B.1.3 Query/Set the Address
Valid addresses are 0 to 9; A through Z; and a through z. The factory default
address is set to 0. The address can be verified by sending the sensor the Address
Query command (see Table B-2).
Table B-2. SDI-12 Command for Querying the Address
Initial Command Response
?!
a<cr><If>
Where a is the current address of the sensor.
Change the sensor’s address by sending the sensor the aAb! command, where “a” is
the original address and “b” is the new address. Table B-3 shows an example of the
command and response for setting the address.