Campbell Scientific SR50-L CSC Ultrasonic Distance Sensor - Manual (Page 11)

SR50 Sonic Ranging Sensor
5
3.1.1 SDI-12 Wiring
FIGURE 1. SDI-12 Wiring
The order in which the connections are made is critical.
Always connect Ground first, followed by +12V and then
the remaining SDI-12/Data Bus, Sensor Enable Line and
Shield. When disconnecting the sensor, the reverse order
should be followed.
The SDI-12 protocol has the ability to support various measurement commands.
The SR50 supports the commands that are listed in Table 1.
Depending on the application, different measurement commands may be
selected. The different commands are entered as options in Parameter 2 of
instruction 105. The major difference between the various measurement
commands is the data that are returned. The user has the options to output the
distance to target in meters or feet, include the measurement quality numbers,
and to include multiple target detection.
The "8" command outputs the first detected echo in meters as in the "0"
command. However, the "8" command disables retries to ensure a fast
measurement. Under poor measurement conditions it may take as long as 3
seconds to obtain a measurement. For users who find this length of time
unacceptable selecting the "8" command ensures that the sensor will complete
the measurement within a one second period by disabling retries.
If the SR50 is unable to detect a proper echo for a measurement, the sensor
will return a zero value for the distance to target value. When the multiple
target output option is selected, the SR50 will return three distance to target
CAUTION
Datalogger
Color Function Connection
Black Ground
Ground (G)
Red +12V +12V
Green SDI-12 Bus Control Port
White Ground Ground (G)
Clear Shield Ground (G)