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python-itho-wpu

A python library and a set of command line tools to communicate with an Itho WPU.

Hardware installation

See the pislave project

Software installation

Install Raspberry Pi OS Lite
Enable SSH and I2C using raspi-config

Install and configure the required software

apt-get install \
    git \              # To clone this repository
    pigpiod \          # Pigpio daemon to communicate over the I2C bus
    python3-pigpio \   # Python module to talk to the pigpio daemon
    python3-pyodbc \   # Python module to access an ODBC database
    sqlite3 \          # To store a subset of the Itho database in SQLite
    direnv \           # Environment variable manager to store credentials for InfluxDB
    python3-influxdb   # To export measurements to InfluxDB

# Set the sample rate value of pigpiod to 10 microseconds to decrease CPU usage
sed -i -e 's/ExecStart=.*/ExecStart=\/usr\/bin\/pigpiod -l -s 10/' /lib/systemd/system/pigpiod.service

# Enable pigpiod service
systemctl enable pigpiod

Install version 0.9.0-1 of odbc-mdbtools

ARCH=$(dpkg --print-architecture)
curl -OL http://snapshot.debian.org/archive/debian/20201218T033640Z/pool/main/m/mdbtools/odbc-mdbtools_0.9.0-1_${ARCH}.deb
curl -OL http://snapshot.debian.org/archive/debian/20201218T033640Z/pool/main/m/mdbtools/libmdb3_0.9.0-1_${ARCH}.deb
curl -OL http://snapshot.debian.org/archive/debian/20201218T033640Z/pool/main/m/mdbtools/libmdbsql3_0.9.0-1_${ARCH}.deb
dpkg -i libmdb3_0.9.0-1_${ARCH}.deb libmdbsql3_0.9.0-1_${ARCH}.deb odbc-mdbtools_0.9.0-1_${ARCH}.deb

When executing convert-itho-db.py with mdbtools version ...

0.7.1-6 (Debian Buster) it fails with: ValueError: the query contains a null character
0.9.1-1 (Debian Bullseye) it fails with: Segmentation fault

Reboot the Raspberry Pi
```
reboot
```

Install python-itho-wpu

git clone https://github.com/pommi/python-itho-wpu.git
cd python-itho-wpu

Extract $_parameters_HeatPump.par from the Itho Service Tool. This is a Microsoft Access database containing details about all WPU versions.
- Download it directly:
```
curl -OL "https://servicetool.blob.core.windows.net/release/Parameters/\$_parameters_HeatPump.par"
```
- Or download the Itho Service Tool and execute AzureBootloader.exe to retrieve the full Itho Service Tool application. $_parameters_HeatPump.par is located in the Parameters directory.
Convert the Microsoft Access database to an SQLite datbase. The SQLite database is used by python-itho-wpu.
```
./convert-itho-db.py --itho-db \$_parameters_HeatPump.par
```

Example usage of python-itho-wpu

Get the NodeID of the WPU

# ./itho-wpu.py --action getnodeid
ManufacturerGroup: 1, Manufacturer: HCCP, HardwareType: WPU, ProductVersion: 25, ListVersion: 11

Get the Serial number of the WPU

# ./itho-wpu.py --action getserial
Serial: 408

Get the Datalog of the WPU

# ./itho-wpu.py --action getdatalog
Buitentemp (°C): 8.0
Boilertemp Onder (°C): 24.23
Boilertemp Boven (°C): 51.68
Verdamper Temp (°C): 19.84
Zuiggas Temp (°C): 21.7
Persgas Temp (°C): 30.22
Vloeistof Temp (°C): 18.67
Temp Naar Bron (°C): 21.09
Temp Uit Bron (°C): 19.75
...

Exporting measurements

InfluxDB

Assuming InfluxDB is running on the Raspberry Pi as well.

Configure a .envrc file

cat > .envrc <<EOT
export INFLUXDB_HOST=127.0.0.1
export INFLUXDB_USERNAME=user
export INFLUXDB_PASSWORD=password
export INFLUXDB_DATABASE=itho
EOT

Allow direnv to load environment variables from the .envrc file
```
direnv allow
```

Execute itho-wpu.pu and export to InfluxDB

./itho-wpu.py --action getdatalog --export-to-influxdb

Alternatively run this in a 5 minute cronjob (the console output is written to /var/log/itho.log)

cat > /etc/cron.d/itho <<EOT
PATH=/usr/bin:/bin:/usr/sbin:/sbin

*/5 * * * * root cd /root/python-itho-wpu && direnv exec . ./itho-wpu.py --action getdatalog --export-to-influxdb >> /var/log/itho.log
EOT

Grafana Dashboard

The measurements collected in InfluxDB can be displayed using a Grafana dashboard.

Download: direct link, grafana.com

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