Sleep Pin hibernate

XBee & XBee Gateway XBee - Zigbee
1

Hello, I have a question about pin hibernate mode. For example, if I have 50 nodes in this mode and all nodes are connected to a single coordinator.
Nodes wake up sequentially every five minutes. Then, is it possible that the nodes are associated with the coordinator?
Thanks,
Regards.

2

Hola Javier,

Yes, the nodes can be configured to keep being associated to the coordinator. The “sleep parameters” SP, ST and SN must be the same in the end-devices and their parents (a parent is the router or coordinator that buffers the messages for an end-device while it sleeps). Consult the product manual to learn more on what values can be set in these parameters. Best regards,

3

Hola a los dos :slight_smile:

I just would like to clarify one issue: Jpdigi is talking of 50 devices, so it should be taken into account the maximum number of end devices supported by a coordinator (10 end devices).

It means that whether you keep nodes associated to the coordinator by increasing SP/SN, it is possible to keep just 10 nodes, and the other 40 nodes will not be associated to the network. You would need to add more routers to the network in order to have all 50 nodes associated (a router supports just 12 devices).

4

Here you have a discussion about to configure SN/SP parameters:

http://www.digi.com/wiki/developer/index.php/XBee_Sleeping_Problems

5

Good point, Daniel! =)

6

Hello, thanks for replies. Good link edpi. Then, if my coordinator has a SN =0x01 and SP=0x20(less than 1 second) within three seconds the coordinator clears the node table.
So, if my devices are in mode pin hibernate and they send them each to a different time, does the coordinator would accept the messages?
Thanks,
Regards.

7

Hi,

In theory yes, but you should be sure that no more than 10 devices are awake at the same time, and it depends on synchronization and the time they remain active before sleeping again.

The issue is that for some chance one node cannot be attached to the coordinator, its message can be lost (maybe your system is not critic).

One way to minimize this possibility is to add some router into the network, so that some nodes are attached to routers.

One question: are nodes fixed or mobile? If fixed, it is much easier to attach them always to the same parent, if mobile not.

Depending on your budget, you can add e.g. 5 nodes, force SN and SP to high values (above 5 minutes), so that a node is always connected to the same parent. You only would need more time to get them attached when deploying the network.

Saludos :slight_smile:

8

Hello, thanks for reply. My idea is the nodes are sleeping always, the mcu wakes every 5 minutes.The MCU will measure a parameter and if it exceeds a value preset, the MCU awakes the antenna and sends a message. I do not think that has more than 10 nodes sending simultaneously.
Other question, how long does it take to join to coordinator? In pin hibernate. Because, I have a node how end device and it takes about 15 seconds.
Thanks,
Saludos.

9

Time to join a coordinator depends whether it is already a child of the coordinator or not.
If it is not, then it can take several seconds.
It is is, it should be almost immediate.

Play with SN and SP to keep end device attached to the coordinator longer, so that further joins are faster.

10

Hello, I tested with the following parameters in the coordinator:

  • SP = 20
    -SN= 1
    In the end devices parameters are:
    -SM = 1, pin hibernate
  • ST= 1388, 5 seconds
    -SP = 20
    -SN = 1
    -SO= 0
    The end devices are connected to the coordinator, but they takes about 15 seconds to join to coordinator. Is there another way to do so to take less time to join?
    What RF technology I can use to avoid this problem?

Regards,
Thanks.

11

Hi,

does it take so long every time the end device wakes or only the first time it joins to the network? I think it should be only the first time.

If it is the case, that time can be reduced fixing the channels used in your network (it is useful it there are not interference sources nearby):

  • Fixing one or two channels on the coordinator/router/end devices, so that time to scan channels can be reduced (SC param)
  • Reducing the time used to scan each channel (SD param)