Echelon Series 6000 Chip databook - Manual (Page 17)

Series 6000 based field devices are capable of running multiple protocols (LonTalk,
LonTalk/IP, BACnet/IP, SNMP, ICMP with UDP sockets available) with a variety of
transceiver options.
Overview of Free Topology Technology
A conventional control system using bus topology wiring (such as an EIA-485 network)
consists of a network of sensors and actuators that are interconnected using a twisted wire
pair. In accordance with EIA-485 guidelines, all of the devices must be wired in a bus
topology to limit electrical reflections and to ensure reliable communications. There is a high
cost associated with installing and maintaining the cable plant that links together the
devices of an EIA-485-based control system. Bus topology wiring is more time consuming
and expensive to install, because the installer is unable to branch or star the wiring where
convenient. All devices must be connected directly to the main bus.
The best solution to reduce installation and maintenance costs and to simplify system
modifications is to use a free topology communications system. Echelon’s free topology
transceiver technology offers such a solution, providing an elegant and inexpensive method
of interconnecting the different elements of a distributed control system.
A free topology architecture allows the installer to wire the control devices with virtually no
topology restrictions. Power is supplied by a local DC power supply located at each device as
shown in Figure 1.
Series 6000 Chip Data Book 5