WSDA
®
-200-USB
User Manual
The Network Settings menu includes Synchronized and Lossless sampling options, while the Node
settings menu offers multiple configuration options to customize the data sampling for a single node, or
a group of nodes.
Figure 14 - Network and Node Configuration Menu
a. Synchronized - By selecting Synchronized, all nodes in the network will periodically synchronize their
time clocks to a beacon that is broadcasted by the WSDA gateway. Each beacon contains a UTC
timestamp, allowing nodes to timestamp their collected data within an accuracy of +/- 50 us.
Each node will also buffer data and transmit this data in time-slots allocated prior to sampling. Using
time-slots assures the transmissions will not “collide”, or corrupt each other. It also provides a means for
efficiently scaling the size of the network to allow as much data throughput as possible.
If Synchronized is deselected, the node will not require a beacon time source and will transmit a data
transmission for each measurement sweep. The user should deselect Synchronized if, either low
latency, or the lowest possible power at slow sample rates, is required.
b. Lossless - The user can achieve near lossless data collection in most environments through the use of
data buffering, radio acknowledgments, and retransmissions. Each node buffers collected data and
timestamps to an internal 2 Mbit FIFO buffer. For each transmission, data is pulled from this buffer. Upon
receiving the data packet, an acknowledgment is sent from the WSDA gateway providing the beacon.
The node will retransmit data until this acknowledgment is received. Inherent overhead in the trans-
mission scheduling protocol assures the node time to recover from periods of poor radio communication.
This feature allows lossless performance in environments where the node achieves as low as 50%
packet error rate. It also allows for operation in situations where the gateway and node move in and out
of range of each other.
The Lossless feature is only available when Synchronized is enabled. Disable Lossless if the application
requires consistent latency or can tolerate lost data.
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