Specifications
Section 11. Programming Resource Library
11-25
TABLE 11.3-1. The SDI-12 basic command / response set.
Courtesy SDI-12 Support Group.
Name Command
1
Response
2
Break
Continuous
spacing for at
least
12 milliseconds
None
Acknowledge Active a! a<CR><LF>
Send Identification aI! allccccccccmmmmmmvvvxxx...xx<CR><LF>
Change Address aAb!
b<CR><LF> (support for this command is required only
if the sensor supports software changeable addresses)
Address Query ?! a<CR><LF>
Start Measurement
3
aM! atttn<CR><LF>
Start Measurement and
Request CRC
3
aMC! atttn<CR><LF>
Send Data
aD0!
.
.
.
aD9!
a<values><CR><LF> or a<values><CRC><CR><LF>
a<values><CR><LF> or a<values><CRC><CR><LF>
a<values><CR><LF> or a<values><CRC><CR><LF>
a<values><CR><LF> or a<values><CRC><CR><LF>
a<values><CR><LF> or a<values><CRC><CR><LF>
Additional Measurements
3
aM1!
.
.
.
aM9!
atttn<CR><LF>
atttn<CR><LF>
atttn<CR><LF>
atttn<CR><LF>
atttn<CR><LF>
Additional Measurements and
Request CRC
3
aMC1! ...
aMC9!
atttn<CR><LF>
Start Verification
3
aV! atttn<CR><LF>
Start Concurrent Measurement aC! atttnn<CR><LF>
Additional Concurrent
Measurements
aC1!
.
.
.
aC9!
atttnn<CR><LF>
atttnn<CR><LF>
atttnn<CR><LF>
atttnn<CR><LF>
atttnn<CR><LF>
Additional Concurrent
Measurements and Request
CRC
aCC1! ... aCC9!
atttnn<CR><LF>
Continuous Measurements aR0! ... aR9! a<values><CR><LF> (formatted like the D commands)
Continuous Measurements and
Request CRC
aRC0! ... aRC9!
a<values><CRC><CR><LF> (formatted like the D
commands)
1
If the command terminator ‘!’ is not present in the command parameter, a measurement command will not be
issued. The 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.