![Campbell SR50AT Скачать руководство пользователя страница 26](http://html1.mh-extra.com/html/campbell/sr50at/sr50at_instruction-manual_488987026.webp)
SR50AT-Series Sonic Ranging Sensors
14
8.3
SDI-12 Measurements
8.3.1 SDI-12 Addresses
The SR50AT can be set to one of ten addresses (0 to 9) which allows up to ten
sensors to be connected to a single digital I/O channel (control port) of an
SDI-12 datalogger.
The SR50AT is shipped from the factory with the address set to 0. The address
on the SR50AT can be changed by sending an SDI-12 change address
command. The change address command can be issued from most SDI-12
recorders. For some Campbell Scientific dataloggers, the SDI-12 transparent
mode will need to be entered to change the address.
When it is necessary to measure more than one SR50AT, it is easiest to use a
different control port for each SR50AT instead of changing the address. If
additional control ports are not available, then the address will need to be
changed.
To change the address of a sensor that has the default address of 0 to the
address of 1 the following command can be sent:
“0A1!”
Only one sensor of the same address should be connected when using the
change address command.
8.3.2 SDI-12 Commands
The SDI-12 protocol supports the SDI-12 commands listed in TABLE
The SR50AT needs to be powered for 1.5 s before it can receive
an SDI-12 command.
The different commands are entered as options in the SDI-12 recorder
instruction. The major difference between the various measurement commands
are the data values that are returned. The user has the option to output the
distance to target in either meters or feet, or to include the measurement quality
numbers.
If the SR50AT is unable to detect a proper echo for a measurement, the sensor
will return a zero value for the distance to target value.
NOTE