Technical data

www.westermo.com Theoretical and general applications 63
L
ON
®
W
ORKS
The Echelon
®
Corporation has, through the introduction of L
ON
WORKS
®
technology,
made available a complete platform to develop open distributed control systems
based on an intelligent network architecture. A L
ON
WORKS
®
system usually consists of
a number of intelligent devices, called nodes, where each node manages a specific task,
for example, measuring a temperature or controlling a valve. The nodes exchange
essential information with each other via the network. A network used for control,
which is based on this distributed intelligence, is known as peer-to-peer architecture.
The nodes do not normally send commands to each other, but exchange data packets
that contain information about for example the temperature, pressure, status, date
and time. The nodes can then use the information in the data packets in different ways
depending on the specific function of the node. Within L
ONWORKS
®
these data pack-
ets can be seen as global variables available on the network and in view of this have
been called network variables. When a node updates a network variable, this is auto-
matically sent out on the network so that other nodes become aware of the new
value. Interoperability is a keyword in L
ONWORKS
®
technology. One of the conditions
for interoperability is that nodes from different manufacturers exchange and under-
stand data without requiring special adaptation of either the software or hardware. In
order to conform to this it is not sufficient to just be on the same network, to have the
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SNVT_state
SNVT_switch
SNVT_temp
SNVT_lux
SNVT_time_stamp
SNVT_alarm
LONWORKS
®
– a data oriented network
B A C K