User's Manual

Table Of Contents
3 ADAM-2000 Series User Manual
Chapter 1 Understanding Your System
1.1.1 IEEE 802.15.4 Wireless Standard
IEEE 802.15.4 is a wireless standard defined as Low Rate Wireless Personal Area
Network (LR-WPAN) or usually called Wireless Personal Area Network (WPAN)
instead. It is designed for low-power consumption and robust wireless communica-
tion, especially for small data packet applications, such as sensor, I/O and etc. IEEE
802.15.4 is a low data rate, low power consumption, low cost, wireless networking
protocol targeted towards automation and remote control applications. It is expected
to provide low cost and low power connectivity for equipment that needs battery life
as long as several months to several years but does not require data transfer rates
as high as those enabled by Bluetooth. The IEEE 802.15.4 standard only defines the
PHY and MAC layers. The working RF are 918MHz for EU, 868MHz for USA and
2.4GHz for W
orld
Wide.
1.1.2 Wireless Sensor Network
The Wireless Sensor Network is based on the IEEE 802.15.4 standard and inherits
all the characteristics. Coordinator, Router and End Device (or called End Node) are
the basic components to perform the PAN.
A coordinator is the data collection center in a PAN and also plays as a gateway to
transfer and translate wireless data to other interfaces, such as RS-232, RS-485,
Ethernet and so on.
A router is a wireless repeater to enhance the wireless signal and a wireless router to
select optimized path for wireless communication between coordinator and end
nodes.
An end node is a wireless remote I/O for data acquisition. The data acquires from
sensors or devices can be transmitted through it. The end node can communicate
with coordinator directly or via a router to coordinator.
As traditional network, the Wireless Sensor Network provides the star, tree and mesh
topologies for various applications.
Table 1.1: Wireless Specifications
Feature(s) IEEE 802.11b Bluetooth IEEE 802.15.4
Data Rate 11Mbps 1Mbps 250Kbps
Power Consumption Hours (High) Days Years (Low)
Connection Very Complex Complex Simple
Connection Speed Up to 3 seconds Up to 10 seconds 30ms
Extendibility Roaming possible No Yes
Reliability Low High High