automatically issues retries and performs other services that make the SDI-12 measurement work
as trouble free as possible.
For troubleshooting purposes, responses to SDI-12 commands can be captured in programmed
mode by placing a variable declared
As String
in the variable parameter. Variables not
declared
As String
will capture only numeric data.
See the CRBasic Editor help for detailed instruction information and program examples:
https://help.campbellsci.com/crbasic/cr300/.
15.6.3 Programming the data logger to act as an SDI-12
sensor
The
SDI12SensorSetup()
/
SDI12SensorResponse()
instruction pair programs the
data logger to behave as an SDI-12 sensor. A common use of this feature is to copy data from the
data logger to other Campbell Scientific data loggers over a single data-wire interface (terminal
configured for SDI-12 to terminal configured for SDI-12), or to copy data to a third-party SDI-12
recorder.
See the CRBasic Editor help for detailed instruction information and program examples:
https://help.campbellsci.com/crbasic/cr300/.
When programmed as an SDI-12 sensor, the data logger will respond to SDI-12 commands
M
,
MC
,
C
,
CC
,
R
,
RC
,
V
,
?
, and
I
.
When acting as a sensor, the data logger can be assigned only one SDI-12 address per SDI-12
port. For example, a data logger will not respond to both
0M!
and
1M!
on SDI-12 port C1.
However, different SDI-12 ports can have unique SDI-12 addresses.
15.6.4 SDI-12 power considerations
When a command is sent by the data logger to an SDI-12 probe, all probes on the same SDI-12
port will wake up. However, only the probe addressed by the data logger will respond. All other
probes will remain active until the timeout period expires.
Example:
Probe: Water Content
Power Usage:
l
Quiescent: 0.25 mA
l
Active: 66 mA
l
Measurement: 120 mA
Measurement time: 15 s
15. Communications protocols
101
