Campbell Scientific SR50A Distance Sensor - Manual (Page 12)

SR50A Sonic Ranging Sensor
SDI-12
Command
Command Function/Description
Values Returned
?! Address Query a
aAb! Change Address command b is the new address
aXM;D.DDD!
Extended
command Set the distance to ground parameter in the SR50A. The distance must be in
meters with no more than 3 decimal places. A
Address is returned
aXI;DDD.DD!
Extended
command Set the distance to ground parameter in the SR50A. The distance must be in
Inches with no more than 2 decimal places. A
Address is returned
aXT;CC.CC!
Extended
command Provide the SR50A with a temperature value to perform on board temperature
compensation. The temperature must be in degrees Celsius with a maximum
of 7 characters including sign and decimal. A
Address is returned
aR0! Returns the Distance to Ground Setting in the SR50A. The units returned are
in Meters DG
aR1! Returns the Distance to Ground Setting in the SR50A. The units returned are
in Inches DG
aR2! Returns the temperature sent to the SR50A for Internal Temperature
compensation. This value remains the same unless power is cycled or a new
temperature values is sent. T
Where a = address of SDI-12 device.
Where n = numbers 1 to 9
NOTE 1: (SR50AT version only)
3.4 RS-232 Operation
The SR50A sensor comes from the factory with the internal jumpers set to
SDI-12 mode. To use the SR50A in the RS-232 mode of operation the jumpers
will need to be set as outlined in Section 7.
3.4.1 RS-232 Wiring
The following table/diagram illustrates the wiring for the SR50A in RS-232
mode.
Color Function Connection
Black Power Ground System Ground and/or RS-232 Receiver
Ground
(Pin 5 of a computer (DTE) DB-9
connector)
Red +12VDC Power Power Source
Green RS-232 (SR50A Output) Recorder/Reader RS-232 Input
(Pin 2 of a computer (DTE) DB-9
connector)
White RS-232 (SR50A Input) Recorder/Reader RS-232 Output
(Pin 3 of a computer (DTE) DB-9
connector)
Clear Shield Shield/Earth Ground
6