User's Manual

XBee®/XBee‐PRO®ZBRFModules
©2009DigiInternational,Inc. 39
Orphan Scans
When an end device comes up from a power cycle, it performs an orphan scan to verify it still has
a valid parent. The orphan scan is sent as a broadcast transmission and contains the 64-bit
address of the end device. Nearby routers and coordinator devices that receive the broadcast
check their child tables for an entry that contains the end device's 64-bit address. If an entry is
found with a matching 64-bit address, the device sends a coordinator realignment command to
the end device that includes the end device's 16-bit address, 16-bit PAN ID, operating channel,
and the parent's 64-bit and 16-bit addresses.
If the orphaned end device receives a coordinator realignment command, it is considered joined to
the network. Otherwise, it will attempt to discover and join a valid network.
XBee: ZB End Device Joining
When an end device is powered on, if it is not joined to a valid ZigBee network, or if the orphan
scan fails to find a parent, it immediately attempts to find and join a valid ZigBee network.
Note: The DJ command can be set to 1 to disable joining. The DJ parameter cannot be written with
WR, so a power cycle always clears the DJ setting.
Similar to a router, the following commands control the end device joining process.
Once the end device joins a network, the network configuration settings can persist through power
cycles as mentioned in the "Persistent Data" section previously. If joining fails, the status of the
last join attempt can be read in the AI command register.
If any of these command values changes, when command register changes are applied, the end
device will leave its current network and attempt to discover and join a new valid network.
Networkjoiningcommandsusedbyanenddevicetojoinanetwork.
Command Description
ID Sets the 64-bit PAN ID to join. Setting ID=0 allows the router
to join any 64-bit PAN ID.
SC Set the scan channels bitmask that determines which
channels an end device will scan to find a valid network. SC
on the end device should be set to match SC on the
coordinator and routers in the desired network. For example,
setting SC to 0x281 enables scanning on channels 0x0B,
0x12, and 0x14, in that order.
SD Set the scan duration, or time that the end device will listen
for beacons on each channel.
ZS Set the stack profile on the device.
EE Enable or disable security in the network. This must be set to
match the EE value (security policy) of the coordinator.
KY Set the trust center link key. If set to 0 (default), the link key
is expected to be obtained (unencrypted) during joining.