Echelon LONWORKS FT 5000, User Manual

Page: 32 / 55

24 Network Cabling and Connection
Figure 12 . Using a Router to Meet the 8-in-16 Topology Rule
The second remedy to a violation of the 8-in-16 rule is to add additional cable to
the bus such that the rule is no longer violated (see Figure 13 ). It is important
to ensure that the maximum bus length (130 meters of 22 AWG [0.65 mm] Level
IV or AWG 24 [0.511 mm] ANSI/TIA/EIA-568-B.2-2001 Category 5 or Category 6
twisted-pair cable) is not exceeded by the additional cable. Because of the
complex interactions between the bus and the transceivers with regard to
reflections and transmission line delays, it is not possible to substitute an LC
network in place of the additional cable to resolve this rule violation.
Figure 13 . Using Additional Bus Cable to Meet the 8-in-16 Topology Rule
Cable Terminations – TP/XF-78, -1250 Segments
Twisted pair network segments require termination for proper data transmission
performance. For doubly terminated bus topologies, a termination must reside at
both endpoints of the bus. The terminations required for TP/XF-78, TP/XF-78F,
and TP/XF-1250 segments are shown in Figure 14 on page 25.