Smart Meter SML Logger is an application to read Smart Meter Language (SML) from a serial port and log the measurements to a Redis Server for further processing.
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Fine resolution power consumption at any time. In my setup I use virtual sensors in Domoticz which are updated with values from a Redis server.
Accumulating power over the day.
The following environment has been tested:
- eHZ Smart Meter with SML status on IR port
- HW is Raspberry PI Zero
- OS is Raspbian Buster-Lite
- Ansible playbook run from Ubuntu 18.04 LTS
The software consists of the following components:
- Forked libsml from Volkszaehler (https://github.com/StefKode/libsml/tree/stable)
- smlogger application
- ansible remote deploymnent
- redis connection manager (https://github.com/StefKode/rediscon)
The libsml implementation from Volkszahler is the best implementation to read the SML protocol from a serial device. It contains a sample sml-server which decodes all received SML objects and writes them to stdout. In the fork this sample server has been modifed to print this data for easy parsing.
Also a script smlmon has been added which publishes the current power consumption and the total power counter to a mqtt broker. None of the core libsml functions has been modifed. I decided for the fork because I re-use he build system to create the modified server.
This is a python script which subscribes to the mqtt messages from libsml. It does averaging and publishes the two power values to a Redis server based on a time trigger. In order to configure the program there is a config file smlogger.conf. This json file has the following keys:
| Config Key | Example value | Description |
|---|---|---|
| redis_server | 192.168.178.10 | redis server hostname or IP address |
| power_current_key | PowerCurrent | redis key to store the current power (Watt) |
| power_day_key | PowerCurrentDay | redis key to store the daily power usage (kWh). This value increments on the day and resets afer 0:00 |
| ts_key | PowerTS | redis key to store capture time stamp |
| mqtt_topic | powlog | this is the topic to which libsml logs the data, this should not be changed |
| update_period | 30 | time interval in seconds at which redis values are updated (must be > 4s) |
| avg_win_size | 5 | size of the sliding average window |
The complete system configuration and the application deployment and configuration is performed using ansible. Make sure ansible has been installed (apt-get install ansible). The ánsible playbook uses a configuration file config.yml:
| Config Key | Description |
|---|---|
| SERVER_HOST | target hostname or IP address where the installation is to be performed |
| TIMEZONE | standardized timezone string (e.g. Europe/Berlin) |
| ASK_PASSWD | set to yes to aks for user password on target or use no if you copied your ssh public key |
Note: as the development has been done on Raspberry PI the user is hardcoded to "pi". You need to change smlogger.yml if you use a different name.
- download rapsbian buster, then configure and enable Wifi and ssh
- setup your Raspberry PI and make sure it is running and reachable
- install ansible
apt install ansible - clone this repository
git clone https://github.com/StefKode/smlogger - in directory deployment create config.yml based on the example file config.yml-example and apply changes as needed
- copy the file smlogger.conf-example to smlogger.conf and apply all settings
- cd into deployment
- type make
The following section outlines some facts of the hardware design.
Tuning: You should leave R1 at maximum and tune R2 to be just above the opening Vube value of the transistor. This is typically 0.7V.
If you would like to support this project then I suggest these tasks:
| Title | Description |
|---|---|
| Adjustment-free schematics | Select a well available and cheap NPN transistor and determine the values of R1 and R2. By this the electronics part would be much simpler to imlement by users without electronics skill |
| pre-built RPI image | create user-ready image for Raspberry PI |
| Web-monitor | create and add a simple web monitoring app for users without a Redis-backend / infrastructure |
| libsml pull request | clean up the smlogger-changes in the libsml example to be accepted by the volkszahler team for a pull request. Alternative: integrate the libsml-app into this repo instead of using a modified libsml repo |