Every group address with no datapoint type, and what it costs you later

Short answer. On the bus, nothing happens. A telegram carries bytes, and the datapoint type (DPT) is a note in ETS that says what the bytes mean. The cost comes later, when a person or a tool must guess.

Where the cost lands

• Tools that read the project. A visualisation, a gateway, a Home Assistant config, a handover document. Is 0x80 on 5/2/14 50% brightness, a scene number or a mode? With a DPT, it is clear. Without one, someone guesses.
• The group monitor. Untyped addresses show raw hex, just when you need to read the log.
• Wrong scale. A 1-byte address can be 5.001 (percent) or 5.010 (a counter from 0 to 255). Read as percent, 200 shows as 78%. Nothing warns you.
• The next integrator. They must work out every type by hand.

Why it happens

ETS often copies the type from the first object you link, and it warns you when objects disagree. Blank types are common on imported or hand-built projects, on projects extended in stages, and where one object can use several types.

Fix it without guessing

Do not guess the type from the address name. Names are personal shorthand and they change from stage to stage.

Use the object. The datapoint type of an object comes from the product’s application program. Match the group address to the object it is linked to. Where the project has an ETS Function role (ETS 5.7 and later), the role also points to the type. Older projects have no roles.

This table shows what roles were set to on one real project, our reference house. It is one example, not a rule.

Role	DPT seen	Count
SwitchOnOff	1.001	30
InfoOnOff	1.011	29
DimRelative	3.007	12
DimValue	5.001	12
InfoDimValue	5.001	11
FunctionUpDown	1.008	5
Stop	1.010	5
SetpointValue / InfoSetpoint	9.001	17 / 17
HvacMode	20.102	17

Status for on/off is often 1.011 (state), not 1.001. But check the product, because some products declare 1.001 on a status object. If the object says 1.001, match it.

ColourValue is not in the table on purpose. On that project it had three types: 232.600 (RGB), 251.600 (RGBW) and 7.600 (colour temperature). A role that means three things cannot fix the type. Someone must decide.

Check this now

In ETS, look through your group addresses for any with an empty data type. Fix those first. Then open the group monitor and confirm the values read correctly.

What Readback reports

Readback lists every group address with no datapoint type. It shows the declared role beside it where there is one, and proposes a type only where the role gives one answer. Where the role is unclear, it says so and stops. On the reference house it reports 113 addressing issues across 668 group addresses. That is a normal project, read carefully.

Run a free Readback. Readback is free to use today.

Next note: Status address or control address