Intro

This program reads information from a Finder 7M.24 power meter connected to a RS485/modbus <-> TCP gateway and saves the output in PostgreSQL database.

Why?

I did not want to share my power meter data to the cloud. At the same time, I am maxing my raspi usage already, so using IoT frameworks such as Node-RED was not an option. I needed a program to query my power meter that can be compiled and not be a memory hog. I also took the opportunity to learn some Rust with it.

Here is the setup for illustrating the context this program runs in:

     220 V
      |                                                                   grafana <> timescale <> converter
      |                                                                         \      |          /   
      v                                                                            \   |       /
Finder 7M.24.8.230.0010 <--- RS485 ---> Waveshare RS485 to ETH (B) <--- TCP/IP ---> RaspberryPI
      |                                          ^                                       ^
      |--------> 12V AC/DC transformer ----------|----------> DC/DC converter -----------|
      v                                          
  Appliances

Usage

1. Set up your power meter and modbus gateway (Power meter should be installed by a certified professional!)
2. Set up psql database (timescale support highly recommended)
3. Checkout the repo
4. cargo build
5. Edit config based on Settings.toml.example
6. Run via cron in interval you like

Reference material

• https://www.findernet.com/en/canada/series/7m-series-smart-energy-meters/
• https://www.waveshare.com/wiki/RS485_TO_ETH_(B)#MODBUS_TCP_Test
• https://www.waveshare.com/w/upload/4/4d/RS485-to-eth-b-user-manual-EN-v1.33.pdf

TODO

Listed in no particular order or priority

• Make the code prettier
• Add production targets for cargo
• Add support for multiple sites and meters (this is mostly db+grafana stuff)
• Publish related grafana dashboards
• Add support for direct serial connection (via RS485 hat on RaspberryPI or USB to serial adapter)