Problems with Xbee s2c (Zigbee) end device sending message to Xbee 3 Pro (Zigbee) as router


I’m having communication problems between an xbee s2c and an xbee3 with the Zigbee protocol.

I have a device that wakes up when some movement occurs and sends a unicast message to another device. This sleeping device has an xbee s2c configured as end device and SM = 1 (Pin Hibernate). When the device wakes up, it wakes up Xbee s2c, waits for the association pin to indicate that Xbee has joined the network. After that, it sends the unicast message, waits to receive the ACK, and then goes back to sleep. There are 4 attempts to send the message for a maximum time of 10 seconds. The device responsible for receiving this unicast message is an Xbee3, which is configured as a router.

The problem that occurs is when the device is sleeping for a time longer than 2 minutes. When this device is woken up after that time, sometimes it takes a while to associate the network, or when it does, it fails to send the message to the destination. If the device is activated later, the xbee s2c sends the message to the router (xbee3) with success.

Does anyone know what may be the cause of this issue and how I can resolve it?

Thank you!

You need to set the parent node to know the maximum time that the sleeping node can sleep for. That is adjusting the SP, ST, SO and SN commands.


Thank you for your reply. My router is configured with theses parameters: SP=7D0, ST=1388, SO=0, SN=5A0. My end device is configured with SM=1, SP=7D0 and SN=5A0.

So the time is 24 hours what my end device must be in child table. But, it doesn’t happen. After 2 minutes sleeping, my end device is not send message to router.

I try to edit the ET parameter in router xbee3 to ET=A (1024 minutes), but the problem still happening.

There is something more that I can do here?

Thank you.

Best regards.

We’ve configured XBee3 to remove the end device from the child table after 24 hours. However, after two minutes the end device is removed from XBee3’s child table, so the NC parameter value increases from 19 to 20. The XBee3 is not taking into account the SP and SN parameters to decide when to remove an end device from the child table.

In my opinion, XBee3 should take into account SP and SN for the child table timeout because the XBee S2C end devices don’t have the ET parameter.

Please, could you try to reproduce the problem?