EMI-Modbus

We adapted the original modbus library and created a lightweight version of it. Ours is also more flexible, but only offers support for the RTU configuration, and only for the modbus_read_input_registers call.

How to run

1. Make sure you have git, make and gcc.

2. Install paho.mqtt.c:

   1. git clone git@github.com:eclipse/paho.mqtt.c.git
   2. cd paho.mqtt.c
   3. make install

3. Install libsystemd-dev:

   1. sudo apt install libsystemd-dev

4. Build the software: make

5. Run it: build/emi-read mqtt://<mqtt-host> <mqtt-user> <mqtt-pwd>

Future steps

1. Code cleanup.
2. Add support for write (so that EMI address can be changed. Might be useful for residential buildings).
3. Allow further customisation via args:
   1. Serial device file name
   2. Interval for instant values polling
   3. Values to poll
   4. We may consider going next level with a yaml config file instead.
4. Contrib flow and guidelines
5. install signal handlers for mqtt logoff and signaling.