Hi, I’m looking. at KNX Hub documentation regarding exposing values to KNX. It says
The integration will broadcast any change of the exposed value to the KNX bus
My question is how often it will send Time to the bus? Will it be every second, minute, or so? I can’t check it at the moment, but need this information.
The documentation here is a bit whacky. It’s once every hour (every xknx sync).
Can I somehow make it every minute?
Not really, no. What would be your usecase?
Actually there wouldn’t be any. Initially I thought that in order to display time for example on sensor I need to send it very often. In other words the time will be as accurate as often is being sent.
Finally I checked Jung documentation page 164 which explains everything
The device possesses an internal clock, set using a communication object. The internal calculation of the current time is primarily influenced by the scope of the internally planned functions and the resulting data traffic. This may cause particularly large time deviations. For this reason, the internal clock should be synchronised on a regular basis. We recommend using, for example, an external KNX/EIB clock with DCF 77 receiver, to set the clock once an hour via the bus and thus keep the deviations as small as possible.
So one hour will be enough for what I need.
I have a follow-up question on this: when I have a KNX device read the time exposed by Home Assistant, will this show the time from the last xknx sync or will it be the actual time?
Use case: I have ordered an energy meter which needs to sync every 15min or so, and I’m getting my Home Assistant ready for it. It explicitly states that it reads the time so it needs to be exposed.
Thomas
Actual time.