Periodic downlink - encodeDownlink() - device joinrequest after ~14 Days

Hello everyone,
I have a problem with a device (Elvaco modules for heat meters).
We switched to Chirpstack V4 from another Lorawan server. So far everything works, join; payload decoder, but the devices send a join request after ~14 days.
Apparently the devices expect some feedback from the LNS so they know they are still connected.
In the old LNS, a downlink was sent after 65 uplink packets (only metadata) and the fCnt kept rising.

Can this also be set in the chirpstack?
Or also with the Javascript function encodeDownlink() ?

I still don’t understand how encodeDownlink() works. Is there an example?
My attempts failed.

Regards, Christian

Depends on what kind of feedback device expects. If it is any kind of downlink message (which should be enought for the device to know it still has connection) then probalby the easiest is to set Device-status request frequency in service profile (v3) or device profile (v4).

there is no device status request in the actual application. But it is set to “1”. It works on my test device in a test application, the only difference is the value for “expected uplink interval”. I adjusted it, the heat meter sends its data every hour. I hope that a device status request will then also be sent to the others.

Another difference would be that I added the test device by hand, the others by grpc. But it shouldn’t have any impact.

Regards, Christian

Expected uplink interval is used in regards to dashboard to distinguish between active/inactive devices, whcich only means how often the Uplink is expected.

Device-status on the other hand also means that server has to send a Downlink message with status request. If set to 1 then it should send 1 request per day.

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i think i have another problem.
Since yesterday, no device status downlink has happened on the affected devices.

There are no link metrics to see. With the test device on my table, these are there and the device status link also works.

I have already deactivated an affected device and entered the app key. but didn’t help.

Anyone an idea?
I created all devices with gRPC (api.DeviceService Create), but the test device by hand. The keys with api.DeviceService CreateKeys. but, as I have now seen, entered the application key of the device in nwk_key and app_key, was that possibly wrong?

Device without links metrics, no device status

test device

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