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National Instruments Corporation
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NI WSN-9791 User Guide and Specifications
Another advantage of the mesh network is the ability to extend the distance of the end measurement
from the wired Ethernet gateway. By placing mesh routers throughout the space where you wish to
acquire signals, you can expand the area and distance across which measurement data can be acquired
and sent. Refer to the
Specifications
section for typical line of sight ranges for the NI WSN devices.
Figure 15 shows how a network can be set up to cover greater distances.
Figure 15.
Network Containing Distance Example
End Node Versus Router
Each NI WSN-32
xx
node can be configured as either an end node or a router. NI WSN-32
xx
nodes are
configured by default at the factory in end node mode. You can change the mode of the node using
the NI-WSN software and NI MAX. One trade-off to consider when configuring nodes is power
consumption. NI WSN-32
xx
nodes configured as end node are designed to be run from battery power
while routers are designed to use external power at all times to send, receive, and buffer messages to and
from end nodes.
Data Transfer in the NI WSN Network
The NI WSN system is built on a low-power, reliable IEEE 802.15.4 network. In order to save power
and increase reliability, this network delivers a maximum theoretical throughput of 250 kbps. This
correlates to a typical maximum rate of 1 sample per second per node.
Measurements taken with NI WSN-32
xx
nodes are single point acquisition. NI WSN-32
xx
devices have
no onboard buffer, therefore the data is considered to be lost, meaning there is no way to retrieve past
data from the device.
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