Specifications

Section 11. Programming Resource Library
11-21
FIGURE 11.3-1. Entering SDI-12 Transparent Mode
through LoggerNet Terminal Emulator
11.3.2 SDI-12 Command Basics
All commands can be issued through SDI-12 transparent mode.
All commands have three components: sensor address, command body, and
command termination.
Sensor address is a single character, and is always the first character of the
command or the subsequent response from the sensor. Usually, sensors are
shipped from the factory with a default address of zero.
Command body and subsequent responses are shown as a combination of
upper and lower case letters. The upper case letters are the fixed portion of the
command, while the lower case letters are the variables or values. All
commands use an exclamation point (!) as command terminator.
The CR1000 datalogger supports the entire suite of SDI-12 instructions as
summarized in TABLE 11.3-1, and defined by the SDI-12 Support Group.
Man
ufacturers establish the command set a specific sensor will respond. This
section discusses the most common commands including: address query,
address change, and sensor acknowledgment and identification. Various ways
to initiate measurement and report data are also discussed. For assistance with
other commands contact a Campbell Scientific Applications Engineer.
11.3.3 Addressing
Wiring more than one SDI-12 probe to a single port requires that each probe
have a unique address. Since the default address on most probes is 0,
additional probes will need the address changed. All SDI-12 version 1.3
probes accept an address of 0 - 9. If more than ten probes are connected to a
common port, lower case “a-z”, and upper case “A-Z” may also be used as
addresses.