Table B-1: Campbell Scientific sensor SDI-12 command and response set
Name
Command
Response
1
Address Query
?!
a<CR><LF>
Change Address
aAb!
b<CR><LF>
Start Measurement
aM!
aM1!...aM9!
atttn<CR><LF>
Start Measurement
and Request CRC
aMC!
aMC1!...aMC9!
atttn <CR><LF>
Start Concurrent Measurement
aC!
aC1!...aC9!
atttnn<CR><LF>
Start Concurrent Measurement
and Request CRC
aCC!
aCC1!...aCC9!
atttnn<CR><LF>
Send Data
aD0!...aD9!
a<values><CR><LF> or
a<values><CRC><CR><LF>
Continuous Measurement
aR0!...aR9!
a<values><CR><LF>
Continuous Measurement
and Request CRC
aRC0!...aRC9!
a<values><CRC><CR><LF>
Extended Commands
aXNNN!
a<values><CR><LF>
1
Information on each of these commands is given in the following sections.
B.1.1 Acknowledge active command (a!)
The Acknowledge Active command (
a!
) is used to test a sensor on the SDI-12 bus. An active
sensor responds with its address.
B.1.2 Send identification command (al!)
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.
aI!
allccccccccmmmmmmvvvxxx...xx<CR><LF>
a
Sensor SDI-12 address
ll
SDI-12 version number (indicates compatibility)
SN500SS Net Radiometer
17
