KNX is a bus system used more on the room and floor level in buildings (e.g. for lighting, shading and local HVAC devices).

The KNX as such doesn´t necessarily need a dedicated controller for simple connection of sensor/switch to receiving/actuator devices.

The signals exchanged via the protocol are so called “group addresses” (“objects”), which are downloaded via ETS to all the thereby linked (=grouped) devices.

On the room level it typically has a serial wiring called KNX TP (twisted pair), which then is linked to floor or central building or management level via IP routers. On Ethernet it is called KNXnet/IP abbreviated also as KNX IP.

After the engineering in Automation Builder, the PLC is a standard KNX device. KNX communication is done via the IP network interface. The PLC is arranged topologically on the area / main line of the KNX IP routers. The PLC communicates with the routers via the KNXnet/IP protocol.