LI-COR LI-7815, Instruction Manual

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Section 7. Communication with the MQTT protocol
Topic Description Hierarchy
1 Data licor/niobrara/output/concentration
2 Header for the data file licor/niobrara/output/concentration/units
3 Diagnostic information for
data licor/niobrara/output/diagnostics
4 Header for diagnostic
information licor/niobrara/output/diagnostics/units
Set and read the calibration
baseline (0) licor/niobrara/cfg/Start_Peak_Base_Line_Cal
Set CO
2
span calibration licor/niobrara/system/CO2_Span
Read the CO
2
span
calibration
licor/niobrara/cfg/CO2_Span
Table 7-1 . Topics and hierarchy in the LI-7815.
Basic commands in a terminal program
The instrument can be controlled from a terminal program (macOS) or command
prompt program (Windows). With trace gas analyzers, that means you can set the
zero and span calibrations, read the calibrations, and read data with diagnostics. In
the following section, we describe how to perform these basic functions.
This tutorial uses Eclipse Mosquitto, an open source message broker from the
Eclipse Foundation which can be downloaded from mosquitto.org/download/.
Install it on your computer. We will use two components of mosquitto for this
tutorial:
mosquitto_pub
, which "publishes" information to the instrument (as in,
sets the span calibration); and
mosquitto_sub
, which "subscribes" to information
from the instrument, such as current calibration parameters, and measurements.
7-2 LI-7815 CO₂/H₂O Gas Analyzer