diematic-server 3.1

Unix daemon and supporting models for publishing data from Diematic DeDietrich boiler

diematic

A Unix service written in Python to monitor De Dietrich boiler equiped with Diematic system using Modbus RS-845 protocol. The service reads data from the boiler and makes it available to be consumed in three ways: Optionally, the values fetched from the boiler are sent to an InfluxDB database. Optionally, the values fetched from the boiler are sent to an MQTT broker. (TODO) Optionally, a RESTful web server is installed and values can be obtained using GET and modified using POST requests. Optionally, boiler parameters can be changed from the mqtt topics

Hardware requirements

• A De Dietrich boiler with Diematic regulation and a mini-din socket
• A mini-din cable
• A RS-845 to USB adapter
• A nano-computer with a USB port and Python3 installed (Raspberry pi or similar)

Check tutorials in the "references" section below on how to do the hardware setup.

Changes from version 2.X

• Added support to integrate with mqtt broker
• Added command line parameters with priority over provided values in the configuration file

Http server

Satrting from version 3.0 the web server can be configured from the diematic.yaml configuration file by adding an http key as follows:

http:
    address: 0.0.0.0
    port: 8080

Once the service is running head to:

http://{HOSTNAME}:{PORT}/diematic/parameters

you can have access to all parameters indicated in the configuration file. Read the webserver.py documentation to know more about it.

MQTT

Starting from version 3.0 the service can be configured to send data to an MQTT broker. The broker configuration goes in the diematic.yaml configuration file as follows:

mqtt:
  broker: your broker server
  port: 1883
  user: your mqtt user, optional
  password: your mqtt user credentials
  retain: false
  tls: false
  topic: diematic2mqtt/boiler
  discovery:
    prefix: homeassistant

If there is no mqtt key, mqtt will not be considered at all. Under the mqtt key only broker key is required. The value is the broker ip address or host name that can be resolved using dns. The port default value is 1883 or 8883 if tls key is set to true. If provided, the user and password keys are used to open connection to the broker. retain can be used to inform the broker to retain the values. topic key can be used to configure the topic under wich all information will be set. if discovery key is set, the server will publish MQTT Discovery information to the broker. The prefix key indicates the topic under wich home assistant is subscribed to receive MQTT Discovery information.

Installation

git clone https://github.com/IgnacioHR/diematicd.git
cd diematicd
python3 -m venv venv
source venv/bin/activate
pip install -r requirements.txt
mkdir /etc/diematic
cp diematic.yaml /etc/diematic
cp diematicd.service /etc/systemd/system
systemctl enable diematicd
systemctl start diematicd

Test

Run python3 diematicd.py --help

usage: diematicd.py [-h] [-b {none,configured,influxdb,mqtt}] [-d DEVICE] [-f]
                    [-l {critical,error,warning,info,debug}] [-c CONFIG]
                    [-w HOSTNAME] [-p PORT] [-s {loop,web,both}] [-a ADDRESS]
                    [-t {Raw,DiematicOneDecimal,DiematicModeFlag,ErrorCode,DiematicCircType,DiematicProgram,bit0,bit1,bit2,bit3,bit4,bit5,bit6,bit7,bit8,bit9,bitA,bitB,bitC,bitD,bitE,bitF}]
                    {status,start,stop,restart,reload,runonce,readregister}

positional arguments:
  {status,start,stop,restart,reload,runonce,readregister}
                        action to take

optional arguments:
  -h, --help            show this help message and exit
  -b {none,influxdb}, --backend {none,influxdb}
                        select data backend (default is influxdb)
  -d DEVICE, --device DEVICE
                        define modbus device
  -f, --foreground      Run in the foreground do not detach process
  -l {critical,error,warning,info,debug}, --logging {critical,error,warning,info,debug}
                        define logging level (default is critical)
  -c CONFIG, --config CONFIG
                        alternate configuration file
  -w HOSTNAME, --hostname HOSTNAME
                        web server host name, defaults to 0.0.0.0
  -p PORT, --port PORT  web server port, defaults to 8080
  -s {loop,web,both}, --server {loop,web,both}
                        servers to start
  -a ADDRESS, --address ADDRESS
                        register address to read whe action is readregister
  -t {Raw,DiematicOneDecimal,DiematicModeFlag,ErrorCode,DiematicCircType,DiematicProgram,bit0,bit1,bit2,bit3,bit4,bit5,bit6,bit7,bit8,bit9,bitA,bitB,bitC,bitD,bitE,bitF}, --format {Raw,DiematicOneDecimal,DiematicModeFlag,ErrorCode,DiematicCircType,DiematicProgram,bit0,bit1,bit2,bit3,bit4,bit5,bit6,bit7,bit8,bit9,bitA,bitB,bitC,bitD,bitE,bitF}
                        value format to apply for register read, default is
                        Raw

InfluxDB preparation

Minimal

CREATE DATABASE "diematic"
CREATE USER "diematic" WITH PASSWORD 'mySecurePas$w0rd'
GRANT ALL ON "diematic" TO "diematic"
CREATE RETENTION POLICY "one_week" ON "diematic" DURATION 1w REPLICATION 1 DEFAULT

Additionnal steps for down-sampling

CREATE RETENTION POLICY "five_weeks" ON "diematic" DURATION 5w REPLICATION 1
CREATE RETENTION POLICY "five_years" ON "diematic" DURATION 260w REPLICATION 1

CREATE CONTINUOUS QUERY "cq_month" ON "diematic" BEGIN
  SELECT mean(/temperature/) AS "mean_1h", mean(/pressure/) AS "mean_1h", max(/temperature/) AS "max_1h", max(/pressure/) AS "max_1h"
  INTO "five_weeks".:MEASUREMENT
  FROM "one_week"."diematic"
  GROUP BY time(1h),*
END

CREATE CONTINUOUS QUERY "cq_year" ON "diematic" BEGIN
  SELECT mean(/^mean_.*temperature/) AS "mean_24h", mean(/^mean_.*pressure/) AS "mean_24h", max(/^max_.*temperature/) AS "max_24h", max(/^max_.*pressure/) AS "max_24h"
  INTO "five_years".:MEASUREMENT
  FROM "five_weeks"."diematic"
  GROUP BY time(24h),*
END

References

• https://github.com/gmasse/diematic.git
• https://github.com/riptideio/pymodbus
• (french) http://sarakha63-domotique.fr/chaudiere-de-dietrich-domotise-modbus/amp/
• (french) https://www.dom-ip.com/wiki/Réalisation_d%27une_Interface_Web_pour_une_chaudière_De_Dietrich_équipée_d%27une_régulation_Diematic_3
• (french forum) https://www.domotique-fibaro.fr/topic/5677-de-dietrich-diematic-isystem/
• (french forum) http://www.wit-square.fr/forum/topics/de-dietrich-communication-modbus-bi-ma-tre
• (french, modbus registers sheets, copy from previous forum) https://drive.google.com/file/d/156qBsfRGJvOpJBJu5K4WMHUuwv34bZQN/view?usp=sharing