My project has duplicate group address names. Is that actually a problem?
Two group addresses with the same name: which one did you mean?
Duplicate names are allowed and give no error. The problem comes later, when someone chooses the wrong row.
Short answer. KNX sends by address, never by name. So 1/1/12 and 1/4/12
can both be called Küche Licht, and ETS will not complain. It is a problem for
you later, not for the bus.
How duplicates start
- Stages. The ground floor was done in 2019 and the extension in 2023. Both
have a
Flur Licht. Neither person was wrong. - Copy and extend. A floor is copied for a new floor and the names come with it.
- Control and status.
Küche Lichtis the name of the command address and of the feedback. This is the most common case. It is also the risky one, because the two act very differently when you write to them.
What it costs
- Group monitor. You filter by name and get two addresses. You must find the right one by hand.
- Visualisation or integration. The tool must choose one. Some tools take the first match and some add a number. You find out when a client says the kitchen switch turns on the hall.
- Handover document. A list with two identical rows must be checked against the project.
- You, in two years. You are the one who has to read it.
How to fix it
Rename, and use a rule, so the names stay unique in the next stage.
- Add the room.
Kücheis not enough in a house with two kitchens. A floor prefix helps. - Add the direction where command and status share a name, for example
statusorcmd. Use the same word everywhere. If you inherited a project without that, see status address or control address. - Rename in ETS, not in another tool. The project file is the record. A fix made elsewhere is lost at the next export.
You do not need to download any device. Names live in the project, not in the hardware. This fix costs only the time to type.
Check this now
In ETS, open the group addresses and sort them by name. Look for rows that repeat. Then check each pair: is it a command and status pair, or two outputs on different floors?
What Readback reports
Readback lists every name that appears more than once, with all the addresses that share it. You can see at once if it is a command and status pair or two different outputs. It also lists other fixes you can make in ETS in minutes: unnamed ranges, addresses with no datapoint type, and addresses outside the range they belong to. It reads the file and changes nothing.
Run a free Readback. Readback is free to use today.
Address problems — duplicate names, listed with every address that shares each one.