Commissioning a KNX house without walking it twice

Short answer. ETS can often show which status address goes with a command, but it is inferred from names and flags, so check it. That pair is a test: send the command, wait for the status. Do this for every pair, and list the outputs that have no status.

What walking the house misses

Walking the house shows the output is alive. You press, the light comes on. These faults still pass:

• An address wired to the wrong room. You pressed in one room and something switched in another.
• A status object nobody wired. The output works, but nothing reports it.
• A dimmer that reports 0% always. It dims well. The feedback is dead.
• A swapped pair, where two outputs are crossed and you tested them in an order that made both look right.

All of these come back later as a callback.

The test list

Each test is a line: send this value to this address, expect this status telegram within this time. Some tests have a tolerance, for example for a dimmer or a valve, because the value may round.

Readback uses these limits as defaults:

• 3 seconds for the status of an electrical output.
• 120 seconds for a blind or shutter, because it must travel.

Some steps only observe. Nothing commands them, so you wait for the telegram.

The list of what cannot be checked

This part matters most. An output with no status address cannot be proved by watching for a reply. The bus never says if the command worked. If the object is readable, it can be polled.

The list names and counts these outputs. For example, a line such as “41 lights will switch and nothing will confirm it” (an example, not real data) is worth more than the other checks around it. You can wire those status objects now, while the project is open.

Nothing here writes to a bus

The test list is a document made by reading a file. A person runs it in the building. Readback does not write to a KNX bus.

Check this now

In ETS, open the group monitor (Diagnostics) and start a recording. Operate one output. Check that the status address sends a telegram, and note how long it took. Repeat for each pair on your list.

What Readback reports

Readback makes a handover test list from your project: the ordered steps, the status telegram expected for each, the limits, and the outputs that cannot be checked because nothing reports on them. You can give it to the client to show what was checked and what could not be.

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

Want to talk through a handover? Book 20 minutes with Ted.

Next note: Your ETS project already knows the rooms