Campbell Scientific CS451/CS456 Pressure Transducer - Manual (Page 40)

Appendix D. SDI-12 Sensor Support
D.1.3 Send Identification Command (aI!)
Sensor identifiers are requested by issuing command aI!. The reply is defined
by the sensor manufacturer, but usually includes the sensor address, SDI-12
version, manufacturer’s name, and sensor model information. Serial number or
other sensor specific information may also be included.
An example of a response from the aI! command is:
013CSI451.Std.01_12345678
Where:
SDI-12 version = 1.3
Manufacturer = CSI
Sensor model = 451
Operating System = .Std 01
Sensor serial number = 12345678
D.1.4 Start Measurement Commands (aM!)
A measurement is initiated with M! commands. The response to each
command has the form atttnn, where
a = sensor address
ttt = time, in seconds, until measurement data are available
nn = the number of values to be returned when one or more subsequent D!
commands are issued.
D.1.5 Aborting a Measurement Command
A measurement command ( M!) is aborted when any other valid command is
sent to the sensor.
D.1.6 Send Data Command (aDv!)
This command requests data from the sensor. It is normally issued
automatically by the datalogger after measurement commands aMv!. In
transparent mode, the user asserts this command to obtain data. If the expected
number of data values are not returned in response to an aD0! command, the
datalogger issues aD1!. TABLE D-2 shows the values returned when using the
send data command.
D-2