Under review

Date and Time capturing to pass on KNX bus

Paul G 3 years ago in Devices / KNX updated 3 years ago 7

There are a couple of similar posts, but none really hits the nail on the head as maybe I have a different problem. BOS server version latest 4.8.14 

The situation is very simple, I want to create three variables (date, time, timestamp) in BOS, which are then mapped or given the same addresses as KNX so BOS effectively populates the KNX addresses and issues the date and time to the KNX BUS. However, there are continues issues, despite several and lengthy testing performed

Current BOS variables created

Image 3131

Current KNX variables created in ETS5

Image 3135

Time, seems to be working fine

Image 3129

Image 3130


  1. First problem, the value type, KNX 11.001, allows for the time, but the time value is actually not populated by BOS
  2. Second problem, if status address is populated in the BOS variable it creates problems for BOS and the date is no longer transmitted/populated
  3. Third problem, the associated KNX variable, spits errors, despite being the same value type

BOS variable

Image 3132

Image 3133

KNX variable

Image 3136

Image 3137

Errors spit in transforming

Image 3134


  1. First problem, the time is not populated, only the hour of the time is, minutes and seconds are not populated
  2. Second problem, the KNX variable is not populated, not a single field

BOS variable

Image 3138

Image 3139

KNX variable

Image 3140

Image 3141

Any thoughts?

Under review


for the 19.001 type, make sure the group addresses are set, otherwise the Year, Month and other values will be 0.

Make sure the "Send System Time" function is enabled with 1 min interval so bOS sends time value each minute.

Make sure the Read flag is also enabled so ETS can read the values from the group address.

We re-tested Date Time, Time and Date addresses separately and together and they all send the values to the bus correctly so if everything is set correctly, it should be working normally.

Best regards-

Hi, guys, thanks for this, though bit unclear

a) KNX group addresses exit and are created, I have access to those through ETS buffer sniffer tool

b) Regarding sending system time, the BOS variable already has it enabled, as the screenshot shows, changing the frequency does not do much, as I tested that in the past, it just clogs up the bus with more messages

c) Read flag, you mean in the group address in ETS or the BoS address?

If you retested on your end, would be easier maybe if the screenshots are posted or shared as part of the knowledge base, otherwise it is difficult to interpret what exactly you guys have done and how it has been set-up, that´s the reason I pasted the examples. For example, if the status address is populated, which is defined in KNX, then BoS stops sending and informing the date and time in two scenarios, maybe another set-up issue, but it has not been addressed.

And this is to proof the point on status addresses, if the status address is popualted BoS ignores the data received

KNX variable defined in ETS, imported to BoS (see the difference with previous version, now the status address is NOT populated)

Now the values show populated, 

This is the state KNX variable imported

So it looks that if I want to populate the state address, I need to create another BoS to populate it from, which is not right, because then the KNX group addresses, variable and state, will always be out of sync between them, it is just impossible to synch them, that´s the whole reason for populating state addressed.  Thoughts on why the status address for DPT 19.001 does notwork?

BoS team any luck to shed some light because this definitively does not work and there is no information anywhere


correct, if you want to send the time values from bOS to KNX you need to enable the Read flag for the group address (images attached).

The address can also be set only under Status address in bOS.

Best regards,time_ets.JPG

thanks guys, will give a a try later in the week