KNX bus interface

Tested with Raspberry Pi OS Release date: January 11th 2021

In this article we will control a KNX relay PLANA 1453 made by Vimar wired as shown below. The relay address was already configured.

Install knxd-tools

sudo apt update
sudo apt install knxd-tools

Setup

Comment this line in /etc/knxd.conf:

# KNXD_OPTS="-e 0.0.1 -E 0.0.2:8 -u /tmp/eib -b ip:"

and add this line in order to use the KNX port available on the CM3-Home board:

KNXD_OPTS="-e 1.1.128 -E 1.1.129:1 -u /tmp/eib -b tpuarts:/dev/ttyAMA0"

Change the User and Group from knxd to root on /lib/systemd/system/knxd.service:

[Unit]
Description=KNX Daemon
After=network.target knxd.socket
Requires=knxd.socket

[Service]
EnvironmentFile=/etc/knxd.conf
ExecStart=/usr/bin/knxd $KNXD_OPTS
#User=knxd
#Group=knxd
User=root
Group=root
Type=notify

Restart=on-failure
RestartSec=10

[Install]
WantedBy=multi-user.target network-online.target
Also=knxd.socket

then reload the systemd definitions:

sudo systemctl daemon-reload

and restart the knxd daemom:

sudo systemctl restart knxd.service

In case of errors check the log messages by typing:

journalctl -f -u knxd

Let's try to control the KNX relay

Relay ON:

knxtool on ip:localhost 1/6/105

Relay OFF:

knxtool off ip:localhost 1/6/105

Links

• Knxd repository on GitHub
• Command line parameters

Sergio Tanzilli
Systems designer, webmaster of www.acmesystems.it and founder of Acme Systems srl

Personal email: tanzilli@acmesystems.it
Web pages: https://www.acmesystems.it --- https://www.acmestudio.it
Github repositories: https://github.com/tanzilli --- https://github.com/acmesystems
Telegram group dedicated to the Acme Systems boards: https://t.me/acmesystemssrl