Individual and group addresses, group objects, commissioning a lighting controller from a laptop on site, and the ETS6 differences that matter for new projects.
1.1.5 means area 1, line 1, device 5. Set once at install via the programming button on the device. Wrong area and the bus refuses to address.
1/0/1 might mean "ceiling lights on/off". Bind any switch's group object to that address and the action propagates. Topology and function are separate concerns.
Each device exposes objects (switch, dim, scene). ETS5 visualises which objects are bound to which group address. Unbound objects are silent bugs.
Always hand the client the .knxproj file. Without it, future modifications mean re-engineering from scratch. Saudi consultants must demand .knxproj in the as-built deliverable.
Numbers that decide whether the system commissions on day one.
| Element | Value / Limit | Used for |
|---|---|---|
| TP1 segment length | ≤ 1,000 m total | Line topology |
| TP1 devices per line | ≤ 64 (256 w/ line booster) | Bus capacity |
| TP1 line voltage | 29 VDC nominal | Bus health |
| IP backbone | IPv4, multicast 224.0.23.12 | Area-to-area routing |
| Group address structure | 3-level: Main/Middle/Sub | Bus messages |
| Power supply rating | 640 mA per line (typical) | Sized to device count |
| Programming current draw | ~10 mA per device | Bus-load planning |
ETS is the database, the topology, and the programmer. Get the structure right at start.
Pick 3-level (Main/Middle/Sub) or 2-level early and stick to it. A 3-level schema (e.g. 1/0/1 = Lighting / Ground floor / Room 1 ON) scales to 8 main groups, 16 middle, 256 sub, enough for any commercial building.
Each TP1 line: max 1,000 m, max 64 devices, single power supply. Need more? Add a line. ETS doesn't enforce this, devices register, but bus collisions and dropouts appear after commissioning if you exceed limits.
From ETS5.7+, security keys are mandatory for new commercial projects. Back up the project keyring; lose it and you can commission new devices but can't re-program existing ones. Owner needs the keyring at handover.
Build reusable templates for typical rooms (office, meeting room, corridor). One template = one group-address block mapped to standard devices. New rooms drop in as copies and re-mapping is hours not days.
Bus monitor, group monitor, and the device info dialog identify 80% of it doesn't work faults in five minutes. Reach for them before re-downloading; downloads kick devices off the bus and can mask the real fault.
We design, commission and hand over KNX BMS projects with ABB controllers, GIRA scenes and MDT actuators, ETS5/6 project files transferred at PC1. Secure keys to owner FM.
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