Elsys CO2 stuck in join-Accept loop

End Devices (Nodes)
1

Hi There!
We recently purchased a Dragino LP8 gateway and an Elsys CO2 sensor. We setup both for 868 band, created the Application on TTN and created the End Node with valid ID’s
Device seems to reach TTN but all we get is
-Forward Join-Accept message
-Accept Join Request

That’s it. No valid payload messages, only continous attempts to reconect

I have already followed some hints related with this issue with no luck

Is there anything I can do to determine if my issue is in the device, gateway, or TTN Setup?

Thanks a lot!

2

What have you tried?

3

I checked the TTN Gateway section and the Activity shows this:

  • 16:01:46 Receive uplink message JoinEUI 0000000000000000 DevEUI A81758FFFE056E04 Data rate SF7BW125 SNR 13.5 RSSI -41
  • 16:01:46 Send downlink message Tx Power 16.15 Data rate SF7BW125
4

I will first move the sensor further away from the gateway (5-10m min and a brick wall in between) – If this is your sensors RSSI.

1 Like
5

Ok we just did move it further, yes 40 was the RSSI.
Now it’s pretty far away (and walls away) from the gateway and we’re still getting join-accepts non stop
What can we check now?

Log from gateway is now the same as above but showing RSSI 50…:frowning:

6

Are you seeing the join request messages in the application or the gateway part of the TTN console?

7

Actually in both.
In application I get:
-Forward join-accept message
-Accept Join-Request
… non stop

And from gateway part of TTN I get the message I posted above (Send uplink JoinEU:xxxxx…Send downlink Tx power 16.15, datarate SF8BW125)

I haven’t seen a real payload message so far…:frowning:
Thanks

8

Check on the gateway what is being logged over there. It might tell you it can’t transmit the data for whatever reason. And when the device doesn’t get an answer it assumes it needs to try again…

9

How quickly is non-stop?

10

Initially every minute, then I seems to realize it’s not working out so it switches to 2 minutes and last retry was after half an hour since the last one
From what I’ve read it’s the current behaviour when the JOIN request don’t work out, tray again but start spacing the requests in time

11

The gateway seems to not realize it’s not working out. It shows
Send Download Link: Tx Power: 16,5, DataRate SF11BW125

Spread Factor changes over time between 7 and 12, probably if the received RSSI changes

Is there any parameter that if misconfigured can still make a JOIN packet reach the TTN but avoid the ACCEPT to get back to the device? All UIDS seem to be right as if not the TTN wouldn’t be sending an ACCEPT message

12

Gateways are a dumb bit of plastic with some sand & other bits fused together - it makes no decisions, it just turns radio in to UDP packets & vice versa.

Almost always the issue is about the device not hearing and the RSSI at -50 is still a bit high which may be overloading the input stage on the device. Please try a larger gap / more walls.

13

What packet forwarder have you configured on the LP8?

14

I’m pretty sure the distance is not being the issue this time, we even tried further with no luck. At least one random join would have got in, but for now absolutely no join attempt has had any success

15

Do you see the live gateway view and in the live application view?

16

I’d suspect the LP8 may be selectively mute - I’ve a client with one - took hours to figure it out.

Can you try your backup TTIG?

17

Unfortunately we don’t have for now an alternate gateway.
Also, we added a second device (totally diferent maker/brand/functionj) and we get the exact same problem (join-accept loop) with the second device as well

What could be wrong in the gateway?

18

I see the gateway info in the TTN side, but I get no more detail on why the messages are not getting back to the device

19

Its owner doesn’t read the posts above?

20

Get a cheap RTL SDR dongle with the right software to confirm the gateway is actually transmitting.