XBP24-DMWIT-250 Digi International, XBP24-DMWIT-250 Datasheet - Page 29

• Manufacturer Part Number: XBP24-DMWIT-250
• Description: XBEE-PRO MESH 2.4 EXTENDED
• Manufacturer: Digi International
• Series: XBEE-PRO™r

Specifications of XBP24-DMWIT-250

• Frequency: 2.4GHz
• Data Rate - Maximum: 250kbps
• Modulation Or Protocol: ISM
• Applications: General Purpose
• Power - Output: 18dBm
• Sensitivity: -100dBm
• Voltage - Supply: 2.8 V ~ 3.4 V
• Current - Receiving: 55mA
• Current - Transmitting: 250mA
• Data Interface: PCB, Through Hole
• Antenna Connector: On-Board, Wire Whip
• Operating Temperature: -40°C ~ 85°C
• Package / Case: Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Memory Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: Q4542387

XBee/XBee‐PRO DigiMesh 2.4 RF Modules
cases it is suggested that these parameters are not modified from the default values.
By default, all new nodes operate in normal (non-sleep) mode. To start a sleeping network, follow these steps:
Alternatively, nodes can be configured with their sleep settings written to flash memory (using the ATWR command)
prior to deployment. If this is the case, the commissioning button and associate LED can be used to aid in deploy-
ment:
Verify that the first node is emitting sync messages by observing its associate LED. A slow blink indicates that the
node is acting as a sleep coordinator.
To add a new node to the network, the node must receive a sync message from a node in the network. On power-
up a cyclic sleep node will periodically send a broadcast requesting a sync message and then sleep for its SP period.
Any node in the network which receives this message will respond with a sync. Because the network can be asleep
for extended periods of time, and as such cannot respond to requests for syncs, there are methods which can be
used to sync a new node while the network is asleep.
Starting a Sleeping Network
Adding a New Node to an Existing Network
Note: The default values of NH and NN have been optimized to work for the majority of network deployments. In most
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Choose NN and NH. Based on the placement of the nodes in your network select appropriate values for the
Select desired duty cycle. The ratio of sleep time to wake time is the factor that has the greatest effect on
A cyclic sleep node in the network which is asleep can be woken via the commissioning button. Place the new
Enable the preferred sleep coordinator option on one of the nodes and set its SM to a sleep compatible mode
Network Hops (NH) and Network Delay Slots (NN) parameters.
Calculate the Sync Message Propagation Time (SMPT). This is the maximum amount of time it takes
for a sleep synchronization message to propagate to every node in the network. This number can be esti-
mated with the following formula:
the RF module's power consumption. Battery life can be estimated based on the following factors: sleep
time, wake time, sleep current, TX current, RX current, and battery capacity.
as well as the sync message. The ST parameter will automatically adjust upwards to its minimum value
when other AT commands are changed that will affect it (SP, NN, and NH). It is suggested that a value larger
than this minimum is used. If a module misses successive sync messages it reduces its available transmit
time to compensate for possible clock drift. It is wise to budget a large enough ST time to allow for a few
syncs to be missed and still have time for normal data transmissions.
(7 or 8) with its SP and ST set to a quick cycle time. The purpose of a quick cycle time is to allow commands
to be sent quickly through the network during commissioning.
message and synchronize themselves to the short cycle SP and ST.
nator is desired).
sleep coordinator then select a node for deployment, power it on, and press the commissioning button twice.
This will cause the node to begin emitting sync messages.
work. If the synchronized node is asleep it can be woken by pressing the commissioning button once.
synchronized.
be able to respond to sync requests promptly.
node in range of the existing cyclic sleep node and wake the existing node by holding the commissioning
button for 2 seconds, or until the node wakes. The existing node stays awake for 30 seconds and will
respond to sync requests while it is awake.
Set the SP and ST values on the sleep coordinator to the desired values for the deployed network.
Wait a cycle for the sleeping nodes to sync themselves to the new SP and ST values.
Power the new node on within range of a sleep support node. Sleep support nodes are always awake and will
Choose Sleep Time and Wake Time. The wake time needs to be long enough to transmit the desired data
If a preferred sleep coordinator is going to be used in the network deploy it first. If there will be no preferred
Next, power on nodes in range of the sleep coordinator or other nodes which have synchronized with the net-
Next, power on the new nodes within range of the sleep coordinator. The nodes will quickly receive a sync
Configure the new nodes in their desired sleep mode as cyclic sleeping nodes or sleep support nodes.
Disable the preferred sleep coordinator option bit on the sleep coordinator (unless a preferred sleep coordi-
Deploy the nodes to their positions.
Wait a cycle for the new node to sync itself.
Verify that the node syncs with the network. The associate LED will blink when the module is awake and
Continue this process until all nodes have been deployed.
SMPT = NN * NH * 16ms
© 2010 Digi International, Inc.
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