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4,000 fiber positioning units need to be positioned precisely in LAMOST(Large Sky Area Multi-object Optical
Spectroscopic Telescope) optical fiber positioning & control system, and every fiber positioning unit needs two stepper
motors for its driven, so 8,000 stepper motors need to be controlled in the entire system. Wireless communication mode
is adopted to save the installing space on the back of the focal panel, and can save more than 95% external wires
compared to the traditional cable control mode. This paper studies how to use the ZigBee technology to group these 8000
nodes, explores the pros and cons of star network and tree network in order to search the stars quickly and efficiently.
ZigBee technology is a short distance, low-complexity, low power, low data rate, low-cost two-way wireless
communication technology based on the IEEE 802.15.4 protocol. It based on standard Open Systems Interconnection
(OSI): The 802.15.4 standard specifies the lower protocol layers-the physical layer (PHY), and the media access
control (MAC). ZigBee Alliance defined on this basis, the rest layers such as the network layer and application layer, and
is responsible for high-level applications, testing and marketing. The network layer used here, based on ad hoc network
protocols, includes the following functions: construction and maintenance of the topological structure, nomenclature and
associated businesses which involves addressing, routing and security and a self-organizing-self-maintenance functions
which will minimize consumer spending and maintenance costs. In this paper, freescale's 802.15.4 protocol was used to
configure the network layer. A star network and a tree network topology is realized, which can build network,
maintenance network and create a routing function automatically. A concise tree network address allocate algorithm is
present to assign the network ID automatically.
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