Digi XBee DigiMesh 2.4, Руководство пользователя

Страница: 69 / 157

Sleep modes Diagnostics
XBee/XBee-PRO DigiMesh 2.4 RF Module User Guide 69
intervals. When this occurs the first task is to repair, replace, and strengthen the weak link with new
and/or redundant devices to fix the problem and prevent it from occurring in the future.
When you use the default DigiMesh sleep parameters, separated subnets do not drift out of phase
with each other. Subnets can drift out of phase with each other if you configure the network in one of
the following ways:
n
If you disable the non-sleep coordinator bit in the SO command on multiple devices in the
network, they are eligible for the network to nominate them as a sleep coordinator. For more
details, see SO (Sleep Options) .
n
If the devices in the network do not use the auto early wake-up sleep option.
If a network has multiple subnets that drift out of phase with each other, get the subnets back in
phase with the following steps:
1. Place a sleep support node in range of both subnets.
2. Select a node in the subnet that you want the other subnet to sync with.
3. Use this node to slightly change the sleep cycle settings of the network, for example,
increment ST .
4. Wait for the subnet’s next wake cycle. During this cycle, the node you select to change the
sleep cycle parameters sends the new settings to the entire subnet it is in range of, including
the sleep support node that is in range of the other subnet.
5. Wait for the out of sync subnet to wake up and send a sync. When the sleep support node
receives this sync, it rejects it and sends a sync to the subnet with the new sleep settings.
6. The subnets will now be in sync. You can remove the sleep support node.
7. You can also change the sleep cycle settings back to the previous settings.
If you only need to replace a few nodes, you can use this method:
1. Reset the out of sync node and set its sleep mode to Synchronous Cyclic Sleep mode ( SM = 8).
2. Set up a short sleep cycle.
3. Place the node in range of a sleep support node or wake a sleeping node with the
Commissioning Pushbutton.
4. The out of sync node receives a sync from the node that is synchronized to the network. It then
syncs to the network sleep settings.
Diagnostics
The following diagnostics are useful in applications that manage a sleeping router network:
Query sleep cycle
Use the OS and OW commands to query the current operational sleep and wake times that a device
uses.
Sleep status
Use the SS command to query useful information regarding the sleep status of the device. Use this
command to query if the node is currently acting as a network sleep coordinator.