CASIENTKNX notes06 entries
Problems worth ten minutes, and what your file says about each one
Written for integrators, not for the people you sell to. Every one of these ends at something the free check finds in your own project, because a page that diagnoses a problem and then shrugs is a blog post.
- 01The light works, but the app says it is on when it is off. Why?Why a KNX light shows the wrong state in Home AssistantThe switching object is bound and the status object is not. The app is running an optimistic state that is correct until somebody touches a wall switch, and it is invisible from the corridor, invisible in ETS unless you go device by device, and completely visible in the project file.Finds it Device coverage — every status object the product declares, against the ones this installation actually wired.5 min
- 02Does it matter if a group address has no DPT set in ETS?Every group address with no datapoint type, and what it costs you laterIt costs nothing on the bus and everything afterwards. The actuator does not care; every tool that reads the project later does, and the cost lands on whoever integrates the house — which is usually you, six months on.Finds it Addressing issues — group addresses with no datapoint type, listed with the ETS Function role that would determine the right one.5 min
- 03I inherited a project where nothing is named. Which addresses are status?How to tell a status address from a control address when nobody named themNot from the name, and not from the address range either. The flags on the communication objects bound to an address settle it, and they are the only evidence in the project that is not somebody's shorthand.Finds it Direction typing — every group address classified by the flags of the objects bound to it, and a list of the ones that are genuinely ambiguous.5 min
- 04My project has duplicate group address names. Is that actually a problem?Two group addresses with the same name: which one did you mean?KNX does not care and will never tell you. Every human and every tool downstream cares, and the failure mode is not an error — it is somebody confidently picking the wrong one.Finds it Addressing issues — duplicate names, listed with every address that shares each one.4 min
- 05How do I prove a KNX install is right before handover, not after?Commissioning a KNX house without walking it twiceWalking the house catches a dead output. It misses the address wired to the wrong room, the status object nobody bound, and the dimmer that reports 0% forever — all of which look fine from the corridor and come back as a callback.Finds it An acceptance protocol — every command, the status telegram it should produce, and an explicit list of what cannot be checked at all.6 min
- 06Why does writing a handover document take a week when the project has it all?Your ETS project already knows the rooms. Your handover pack does not.The building structure, the device schedule, the room-by-room breakdown and the parameters behind every behaviour are all in the file. They are just in a form nobody can hand to a client, which is why the document gets written by hand or not at all.Finds it A handover document generated from the project — building structure, device schedule, and the device-local behaviour that appears in no documentation.5 min
Every one of these is in a project file you already have.
Drop it in and find out which of them are in yours. Free, permanently. No card. You do not talk to anyone unless you want to.