Installation guide

WIring Topologies
Free Topologies
When using free topology cabling, the only criteria that matters is the total length of cable. Star and
loop confgurations are both supported. As the chart below illustrates, Low impedance Cat V cable
allows for a total of 400 meters of cable in any one segment. Up to 63 devices can exist in any one
segment. If you need to go farther you can add a repeater which separates your wiring into two seg-
ments. Free Topology is terminated with a single 52 ohm resistor preferably located towards the cen-
ter of the segment. Loop topology has the advantage of redundancy. If for any reason that the loop
gets cut, the network will not stop functioning unless the network has a direct short at the point where
damaged. Free topology is very forgiving and may appear to work just fne without the termination
resistor, but it still important to place this resistor on the trunk-line especially on very short or very long
distances to ensure good data fow and avoid network collisions. The Echelon communications line is
not polarity sensitive. Several examples are provided here.
10
REV 2.0