Campbell Scientific CR200/CR200X-series Dataloggers - Manual (Page 127)

Section 11. Programming Resource Library
11.4.1.2.1 Start Measurement Command (aMv!)
Qualifier v is a variable between 1 and 9. If supported by the sensor
manufacturer, v requests variant data. Variants may include:
• alternate units (e.g. °C or °F)
• additional values (e.g., level and temperature)
• diagnostic of the sensor’s internal battery
Example:
Command: 5M!
Response: 500410 (atttnn, indicates address 5, data ready in 4 seconds, will
report 10 values).
Example:
Command: 5M7!
Response: 500201 (atttnn indicates address 5, data ready in 2 seconds, will
report 1 value). v = 7 instructs the sensor to return the voltage of its internal
battery.
11.4.1.2.2 Start Concurrent Measurement Command (aC!)
Concurrent measurement allows the CR200(X) to request a measurement,
continue program execution, and pick up the requested data on the next pass
through the program. The datalogger scan rate should be set such that the
resulting skew between time of measurement and time of data collection does
not compromise data integrity.
Note This command is new to Version 1.2 or higher of the SDI-12
Specification. Older sensors, older loggers, or new sensors that do not meet
v1.2 specifications will likely not support this command
11.4.1.2.3 Aborting a Measurement Command
A measurement command (M! or C!) is aborted when any other valid command
is sent to the sensor.
11.4.1.3 Send Data Commands (aDv! & aRv!)
11.4.1.3.1 Send Data Command (aDv!)
This command requests data from the sensor. It is normally issued
automatically by the datalogger after measurement commands aMv! or aCv!. In
transparent mode, the user asserts this command to obtain data. If the expected
number of data values are not returned in response to a aD0! command, the data
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