RAK7249 Downlink problem

[Tibo (thibault)]

Issue: Software

Setup: .RAK7249 / Ethernet EU

LoRa® Server: Buildin, packet forwader (no TTN)

Details: Cannot send downlink using the RAK7249 web app.

I have Adeunis Dry Contact 2 sensors (Class A). Uplink works fine, but I cannot send downlink messages to the sensor using the RAK webapp.

The RAK gateway configuration is pretty standard, using the local Lora Server (no TTN).

When I send the downlink, I don’t see anything in the Packet Logger or in the Live Device Data panels.

Is there is configuration to set in the gateway to make the downlink working?

Any help is welcome…

[Tibo (thibault)]

IT works. The problem came from the downlink encoding.

But, downlink are very slow. I need to wait around 5 mn before to receive the ACK and reply from the sensor. Sometime, the sensor ACK when it send another uplink message, waiting 30 mn or more…

Is the latency come from the Gateway, or from the sensor?
Is there is a way to reduce it?
I use this sensor to switch off/on a water pump to fill a water tank from a well, so latency is a problem…

Thanks.

[nmcc (Nick McCloud)]

Downlinks are only sent when the a Class A device uplinks.

So the latency is all about the how often the device sends data.

LoRaWAN on Class A is not a great solution for explicitly controlling something - ideally the device knows what to do and downlinks are to adjust settings.

[Tibo (thibault)]

Now I understand why the sensor has a parameter “Transmission period of the Keep Alive frame”, just to pool the downlink messages.
Thanks Nick for your reply.

[carlrowan]

If I may add @Tibo , that limitation is only applicable on Class A. If your device can work on Class C, it can receive any downlink message instantly because it is Constantly listening

Class C = Constantly listening.