Campbell Scientific CR200/CR200X-series Dataloggers - Manual (Page 126)

Section 11. Programming Resource Library
11.4.1.1 Addressing
A single probe should be connected to an SDI-12 input when using these
commands.
11.4.1.1.1 Address Query Command (?!)
Command ?! requests the address of the connected sensor. The sensor replies to
the query with the address, a.
11.4.1.1.2 Change Address Command (aAb!)
Sensor address is changed with command aAb!, where a is the current address
and b is the new address. For example, to change an address from 0 to 2, the
command is 0A2! The sensor responds with the new address b, or in this
example 2.
11.4.1.1.3 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:
013NRSYSINC1000001.2101 <CR><LF>
where:
• Address = 0
• SDI-12 version =1.3
• Manufacturer = NRSYSINC
• Sensor model = 100000
• Sensor version = 1.2
• Serial number = 101
11.4.1.2 Start Measurement Commands (aM! & aC!)
A measurement is initiated with M! or C! 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.
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