Campbell MetSENS Series - Stopping a Measurement Command; Send Data Command (Ad0; SDI-12 Transparent Mode

B.1.8 Stopping a measurement command
A measurement command (aM!) is stopped if it detects a break signal before the measurement is
complete. A break signal is sent by the data logger before most commands.
A concurrent measurement command (aC!) is aborted when another valid command is sent to
the sensor before the measurement time has elapsed.
B.1.9 Send data command (aD0! … aD9!)
The send data command (aD!) requests data from the sensor. It is issued automatically with
every type of measurement command (aM!, aMC!, aC!, aCC!). When the measurement
command is aM! or aMC!, the data logger issues the aD0! command once a service request has
been received from the sensor or the reported time has expired. When the data logger is issuing
concurrent commands (aC! or aCC!), the send data command is issued after the required time
has elapsed (no service request will be sent by the sensor). In transparent mode (see SDI-12
transparent mode [p. 29]), the user asserts this command to obtain data.
Depending on the type of data returned and the number of values a sensor returns, the data
logger may need to issue aD0! up to aD9! to retrieve all data. A sensor may return up to 35
characters of data in response to an aD! command that follows an aM! or aMC! command. A
sensor may return up to 75 characters of data in response to a aD! command that follows an
aC! or aCC! command. Data values are separated by plus or minus signs.
Command: aD0! (aD1! … aD9!)
Response: a<values><CR><LF> or a<values><CRC><CR><LF>
where
a = the sensor address
<values> = values returned with a polarity sign (+ or –)
<CR><LF> = terminates the response
<CRC> = 16-bit CRC code appended if data was requested with aMC! or aCC!.
B.2 SDI-12 transparent mode
System operators can manually interrogate and enter settings in probes using transparent mode.
Transparent mode is useful in troubleshooting SDI-12 systems because it allows direct
communication with probes. Data logger security may need to be unlocked before activating the
transparent mode.
Transparent mode is entered while the computer is communicating with the data logger through
a terminal emulator program. It is accessed through Campbell Scientific data logger support
MetSENS-Series Compact Weather Sensors 29