Sunset/-rise without internet

[PolymorphedCust]

Hi

We have 3 LM which control the light in a park. The 3 LM's may not get online, so they can't communicate in any way. 
For sunset and sunrise switching it feels like it's drifting, making the switch-on and -off insimultanious. 

We have set the long- and latitude on each LM for out exact location.

How do we make sure it switches on at the same time in the best way? 

I did realize some of the LMs had drifted in it's time, so I also adapted the time from my Windows to all 3 LMs, but the problem persists..

Thanks in advance.

[Daniel]

LM Real time clock has some accuracy and yes if no internet then the time will adrift over time. In this case when time is critical it would be best to get a KNX gps timer and then update LM os.time from it.

[admin]

Another possible solution: https://forum.logicmachine.net/showthread.php?tid=2941

[Steve ASG]

I made an ipk that can sync time to phone or pc connected to the lan even if internet not availible for this purpose. but to sync multiple LM without a network between them is different again