Campbell Scientific CR200/CR200X-series Dataloggers - Manual (Page 125)

Section 11. Programming Resource Library
SDI-12 commands and responses are defined by the SDI-12 Support Group
(www.sdi-12.org) and are summarized in TABLE. Standard SDI-12 Command
& Response Set (p. 113). Sensor manufacturers determine which commands to
support. The most common commands are detailed below.
Table 14. Standard SDI-12 Command & Response Set
Name Command 1 Response 2
Break Continuous
spacing for at least
12 milliseconds
None
Acknowledge Active a! a
Send Identification aI! allccccccccmmmmmmvvvxxx...xx
Change Address aAb! b (support for this command is required only
if the sensor supports software changeable addresses)
Address Query ?! a
Start Measurement 3 aM! atttn
Start Measurement and Request
CRC 3
aMC! atttn
Send Data aD0!
.
.
.
aD9!
a or a
a or a
a or a
a or a
a or a
Additional Measurements 3 aM1!
.
.
.
aM9!
atttn
atttn
atttn
atttn
atttn
Additional Measurements and
Request CRC 3
aMC1! ... aMC9! atttn
Start Verification 3 aV! atttn
Start Concurrent Measurement aC! atttnn
Additional Concurrent
Measurements aC1!
.
.
.
aC9!
atttnn
atttnn
atttnn
atttnn
atttnn
Additional Concurrent
Measurements and Request CRC aCC1! ... aCC9! atttnn
Continuous Measurements aR0! ... aR9! a (formatted like the D commands)
Continuous Measurements and
Request CRC
aRC0! ... aRC9! a (formatted like the D
commands)
1 If the terminator '!' is not present, the command will not be issued. The CRBASIC SDI12Recorder () instruction, however, will
still pick up data resulting from a previously issued "C!" command.
2 Complete response string can be obtained when using the SDIRecorder () instruction by declaring the Destination variable as
String.
3 This command may result in a service request.
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