Campbell Scientific Wireless Sensor Network (CWB100, CWS220, and CWS900) - Manual (Page 10)

Wireless Sensor Network
station synchronizes wireless sensor measurements and polls all sensors,
storing the collected measurements so that it can transfer them as soon as the
datalogger requests them. This minimizes the amount of time the datalogger
needs to wait for a response from the network through the CWB100 base
station. At the start of each polling interval the datalogger polls the base
station and sensor values are transferred to the datalogger for storage. This
method of data transfer from the sensors to the datalogger provides the fastest
and lowest power method available. An optional configuration string file may
be downloaded to the datalogger to predefine sensor and field names along
with the order in which values are returned to the destination array.
In order to conserve battery power, the sensors do not initiate any
communication except during Network Discovery. Instead they transmit only
when polled by the base station.
1.2 CWB100 Wireless Base Station
The CWB100 is the master radio in the wireless sensor network and serves as
the interface between the datalogger and the wireless sensors. It holds
information for the routes to all the sensors in the network and is responsible
for polling the sensors. It synchronizes wireless sensors to make their
measurements at the beginning of the datalogger’s scan. The CWB100
communicates using serial protocol or USB.
The CWB100 is packaged in an extruded aluminum housing, and needs to be
sheltered in an enclosure. It has a terminal block for connecting power and
data lines from the CWB100 to the datalogger wiring panel. It also has a USB
port for connection to a computer during configuration. The CWB100 is
powered through either the USB connector or the terminal block.
FIGURE 1.2-1. CWB100 Wireless Base Station
For specifications of the CWB100, see Section 2.2.
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