XBP09-DMDK Digi International, XBP09-DMDK Datasheet - Page 17

• Manufacturer Part Number: XBP09-DMDK
• Description: KIT STARTER PROMESH XBEE PRO
• Manufacturer: Digi International
• Series: XBEE-PRO™r
• Type: Transceiver, XBeePror

Specifications of XBP09-DMDK

• Frequency: 900MHz
• Wireless Frequency: 900 MHz
• Interface Type: RS-232, USB, UART
• Modulation: FHSS
• Security: 128 bit AES
• Operating Voltage: 3.3 V
• Output Power: 50 mW
• Antenna: RPSMA
• For Use With/related Products: Xbee-PRO Modules
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 602-1130

XBee‐PRO® 900 OEM RF Modules
Operation
Normal Mode
Nomination
Election
Preferred Sleep Coordinator Option
Programming Sleep Time Intervals
Starting a Sleeping Network
Normal mode is the default mode for a newly powered on node. In this mode a node will not sleep,
but will synchronize to a sleeping network. When synchronized a normal node can aid in setting up
and maintaining a synchronized network by responding to synch message requests from nodes in
cyclic sleep mode (SM4) by sending a special unicast synch message.
Note: Although a normal node can synchronize to a sleeping network, it will not defer data
transmission during sleep. A normal mode node synchronized to a sleeping network can be used
for maintenance purposes such as adding new nodes to the sleeping networks.
Nomination is the process where a node becomes a sleep coordinator at the start of a sleeping
network or in the event a sleep coordinator fails as a replacement. This process is automatic with
any sleeping node being eligible to become the sleep coordinator for the network. This process can
be managed through SO by allowing a node to alter the algorithm used for nomination giving the
node a greater chance to become the sleep coordinator. This option is designed for maintenance
purposes and is not necessary for cyclic sleep operation.
If the node has the preferred sleep coordinator option-enabled (SO=1), then it will poll during its
first cycle for a synch message. If it becomes synched by receiving a synch message, it will cycle
back to sleep and will not become the sleep coordinator. If it does not become synched during that
first cycle, then it will nominate itself as the sleep coordinator and will start sending synch
messages at the start of its second cycle.
Any sleeping node, if it does not receive a message for three cycles, may nominate itself to act as
a replacement sleep coordinator. Depending on the platform and other configured options, such a
node will eventually nominate itself after a number of cycles without a synch. If preferred sleep
coordinator option is enabled, a sleeping node will nominate itself immediately after one cycle
without a synch message.
If multiple nodes nominate themselves at the same time, then an election will take place to
resolve which node will function as the network's sleep coordinator. A node will disable synching if
it receives a synch message from a senior node. A node running in normal mode (with preferred
sleep coordinator option enabled) is senior to any node operating in sleep mode. A node with the
largest MAC address value is senior to any other node operating in the same mode.
The preferred sleep coordinator option is
Enabling this bit will cause a node operating in normal mode to act as a sleep coordinator or cause
a sleeping node to nominate itself after one cycle without receiving a synch message. Setting a
normal mode node to act as a sleep coordinator can be used to start a network. After the network
is set up the normal node can be turned off if no longer needed. A sleeping node, after several
cycles, will elect itself as the sleep coordinator. Designating a cyclic sleep mode node as a
preferred sleep coordinator is useful where a node or nodes are conveniently positioned for
maintenance. It is also useful when enabled on a centrally located node to minimize the number of
hops a synch message must take to get across the network.
The commands for programming sleep time intervals are
By default, all new nodes operate in normal mode. To start a sleeping network, follow these steps:
© 2008 Digi International, Inc.
• SO = 1 - preferred sleep coordinator.
• SP - sleep time
• ST - wake time.
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