#Thank you for reply farmio!

1 messages · Page 1 of 1 (latest)

dense pond
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When you use Routing, you don't "connect" to a router, but broadcast to all routers in the network (multicast). So when you send "ON" to a group address (GA) - say "1/2/3" - all routers receive and forward that based on their filter tables.

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if you used "1/2/3" in both your separate projects, both routers would forward that and some actuator will probably do some action.

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If you share a GA pool, it means you don't use one GA in both projects for different things. So it is essentially one project split in two - which is probably quite hard to keep in sync though...

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So if you implement some kind of schema, like many do, say

1 - light
x/2 - kitchen
x/y/3 - brightness

it would not work properly for both projects as a telegram to 1/2/3 would set the kitchen light brightness for both kitchens.

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if you separate that eg. use 10/2/3 for the second project, it would work.

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The one instance limitation is an implementation thing. It was built this way from the beginning of the knx integration and would be quite a big breaking change to support multiple entries for a quite narrow user base. This feature request I have seen from like 3 people (including you) in the last 5 years or so.

dawn locust
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I think I need to go a little bit slower. So, telegrams for KNX that are sent from HA are sent on multicast address.? Each KNX router listens for these telegram.

dense pond
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If you use "routing" then yes.

dawn locust
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Yes, so my IP router has to be configured for routing.

dense pond
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"tunnelling" (ip interfaces, not routers, although all routers can do that too) is a direct communication channel between HA and one knx gateway

dawn locust
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Thank you for explanation.
I am a little bit confused. What is the purpose of the IP router unicast IP address, for the KNX purposes? Why do I need to enter the IP address of the router when creating knx configuration in HA?

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Just to be clear, the devices are identified in the KNX by device addresses. Each device in the same segment has to have the same group address?

dense pond
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Why do I need to enter the IP address of the router when creating knx configuration in HA?
you don't - if you select "routing" you may configure a multicast group

dense pond
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IAs are used for configuration purposes (HA doesn't do that. ETS does)

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GAs are used for normal communication - sensor data, commands etc.

dawn locust
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Yeah, sound like missunderstood the concept of the knx communication in the first place

dense pond
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it is sent to a GA. not a corroesponding device, but all devices. All GA communication is broadcast (segmented through filter tables of line couplers and IP routers to keep bus load smaller)

dawn locust
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Yes, so the message will "reach" only the devices with the corresponding group address.

dense pond
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It will reach all devices. Those who dont use the GA ignore it.

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A device may listen to lots of GAs

dawn locust
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Nice explanation, thank you so much! Maybe, if I will write an example of group addresses usage in my project, can you please check it out so I will be sure, I understood the concept?

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Also, the routers has to be configured as an area couplers for each segment.

dense pond
dense pond