Maximum telegrams in queue

[shinsuke imai]

What kind of queue can we set here?

KNX connection > General > Maximum telegrams in queue

How should we set the correct maximum number?

[admin]

This is KNX/TP send queue. Any new messages are discarded if the queue is full. Usually this parameter should not be modified. If your KNX/TP is overloaded you should either split it into several segments connected via IP or rework your system architecture to lower the bus load.

[shinsuke imai]

Thank you for your reply.
We send some commands to eibd at the same time. For example, when we go to the bed, we turn off all devices.
I understand we should use KNX scene for this kinda command.
However, we are looking for something to avoid losing commands as a workaround.
I'll check how it works when we set the queue as 1000.

[Daniel]

How many telegrams do you send?

[admin]

For "all off" command you should use a single group address to turn off all relevant devices at once. But an overload issue might arise from the status telegrams coming from all affected devices at once. Another approach is to use LM scenes to turn off each device separately but with a small delay between each write.

[shinsuke imai]

> How many telegrams do you send?

We have over 20 object on a LM scene. The requirement is changing the lights in one room at once without delay as possible.
The room is so big. Changing light's illuminance one by one looks not cool.

We think that using DALI scene is the one option for this. Export this scene, build xml file for DALI module, import it and download into it.

> But an overload issue might arise from the status telegrams coming from all affected devices at once.

As you said, even if we move the scene to DALI scene, this could be happen. We are testing it now.

[admin]

DALI bus is much slower than KNX. There will be a noticeable delay if you try to control each ballast separately. You should switch to using DALI scenes. Most DALI gateways use polling for ballast status so it won't overload KNX because it takes some time to get status from all ballasts.