PV284 Colloquium Project
Alice Bob Eva
November 2023
1 Project brief description
The project is an example of meteorological station data collection system. The system consist
of three nodes: Node A - the meteorology station itself collects data, Node B is a data broker
connected to meteorology station by Modbus and offering data to upper-layer applications via
MQTT protocol, and node C presents the long-term data to end users via Grafana. The overall
structure of the project can be seen from picture 1.
Node A Node B Node C
MODBUS
Meteorology
station
Broker
Data
processing
TCP/IP
Figure 1: The overall project structure.
2 Project solution
The project solution was straightforward, no meaningful obstacles faced. Node A runs on IoT
Lab equipment consisting of STM32 MCU module, RS-485 communication module and application
board containing all necessary sensors. Node B runs on IoT Lab equipment consisting
of RockPi S CPU module, RS-485 communication module, and application module containing
LCD display. The display was used for debugging purposes. Node C runs on a virtual machine
on Stratus.FI, using Debian 12 image offered by CVTFI as a template. Modbus protocol is
based on the library [1].
Modbus address of the Node A was 35, the input registers are assigned as follow:
300100 Temperature
300200 Relative humidity
300300 Barometric pressure
Alice contributed the software for STM32 MCU on Node A.
Bob was responsible for the Node B.
Eva contributed the configuration of Grafana data collector and web interface.
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3 Conclusion
This simple example can be easily extended to more complex project containing mode sensing
units on the Modbus and/or more brokers offering data to the cloud application represented by
the Grafana in our case.
References
[1] https://www.arduino.cc/reference/en/libraries/arduinomodbus/
4 Appendixes
4.1 Software of node A
The software for STM32 was prepared on Arduino IDE. The source code is here: The source
code goes here.
4.2 Software of node B
The software for Node B - the RockPi S - was prepared in Python/C/Bash/... : The source
code goes here. In case of more files, please put a 1-2 lines comment on each.
4.3 Software of node C
Node C runs on a virtual machine on Stratus. A standard grafana package was used, the
configuration file is here: The config file(s) goes here.
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