Engineering Documentation

Table Of Contents
Chapter 2 Network Electrical Systems
RS-485 ALN and FLN (P1) Communications Wiring on Structured Cabling
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Use of Shielded and Unshielded Twisted Pair Cable
Shielded Category 5 cabling is used where excessive noise is expected on the
information system cabling, for example, when it is near a high-power transmitter. In
these cases, the same shielded Category 5 cable will be used for the RS-485 ALN
and FLN trunks.
CAUTION
Use an HSTIE to isolate different wire types, such as shielded zone trunk
cabling and SCS UTP.
Mixing wire types will result in loss of signal integrity and possible loss of RS-485
ALN or FLN communications.
Sheath Sharing and Cable Routing
Use separate binder groups (a group of 4 or 25 cable pair cables in same sheath)
for building automation system signals. Use blue binder group for HVAC.
A riser cable may have many 25 pair binder groups. Building automation system
signals and voice and data signals can share the same riser cable, but not the
same binder group.
Horizontal binder groups can have either 25 cable pairs or 4 cable pairs. Building
automation system signals and voice and data signals can share the same cable
tray, but not the same binder group.
Use a 4-pair (blue) binder for each separate ALN.
Use a separate 4-pair (blue) binder for FLN1, FLN2, and FLN3 on each Field
Panel Controller. These FLN signals are multiplexed and may share the same
binder. Do not mix with FLN signals from other controllers.
CAUTION
MLN, AEM ALN, and other Ethernet protocol signals do not use the same
interconnects and must not share the same binder group as RS-485 ALN or FLN
signals. Mixing Ethernet protocol signals within the same binder group will result in
loss of signal integrity and possible loss of RS-485 ALN or FLN communications.
Fig. 27: Components of an SCS 4 UTP Cable.