Communications; Transparent Mode - Campbell CR300 Series Product Manual

19.7 SDI-12 communications
SDI-12 is a 1200 baud communications protocol that supports many smart sensors, probes and
devices. The data logger supports SDI-12 communications through two modes — transparent
mode and programmed mode (see
Transparent mode facilitates sensor setup and troubleshooting. It allows commands to be
manually issued and the full sensor response viewed. Transparent mode does not record data.
See SDI-12 transparent
Programmed mode automates much of the SDI-12 protocol and provides for data recording. See
SDI-12 programmed mode/recorder
CRBasic SDI-12 instructions include:
SDI12Recorder()
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SDI12SensorSetup()
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SDI12SensorResponse()
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SDI12Watch()
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See the CRBasic Editor help for detailed instruction information and program examples:
https://help.campbellsci.com/crbasic/cr300/
The data logger uses SDI-12 version 1.4.
19.7.1 SDI-12 transparent mode
All SDI-12 probes have just three wires—a signal, ground, and 12 V power line. They are
connected to the data logger according to the following table.
Table 19-1: SDI-12 probe connections
Wire function Data logger connection
SDI-12 signal C1, C2
Shield G
Power 12V
Power ground G
System operators can manually interrogate and enter settings in probes, connected to the data
logger, using transparent mode. Transparent mode is useful in troubleshooting SDI-12 systems
because it allows direct communications with probes.
SDI-12 ports (p. 15) for wiring terminal information).
mode (p. 181) for more information.
mode (p. 139) for more information.
.
19. Communications protocols 137