Fire-Lite LCD-80FC Remote Fire Indicator - Manual (Page 21)

LCD-80FC Instruction Manual — P/N 53244:B 5/13/2013 21
Shield in Full Conduit EIA-485 Shield Termination
5.2 Shield in Full Conduit
The EIA-485 line allows the FACP to communicate with the LCD-80FC Indicator. The shield for
the EIA-485 line must be connected to earth ground at the FACP (both exiting and entering the
FACP) but must be left floating (no connection) at the indicator if it is the first or only device on the
EIA-485 line. If a second indicator is connected, the shield leaving the first indicator must be float-
ing. The shield entering the second indicator must be connected to the Earth Ground terminal (P2-
7) on the second indicator. If additional indicators are connected, the shield leaving each indicator
must be left floating and the shield entering the following unit must be connected to the Earth
Ground terminal (P2-7) on the indicator.
!
CAUTION: INSULATE FLOATING END
DO NOT ALLOW THE FLOATING SHIELD END (NO CONNECTION) TO CONTACT THE
CONDUIT. THE FLOATING END SHOULD BE INSULATED FROM EARTH GROUND.
LCD-80FC Box
LCD-80FC
P1-2 (+)
EIA-485 (IN)
P1-4 (-)
EIA-485 (IN)
P2-7 Earth
Ground (IN)
Connect the shield drain wire to the Earth
Ground Terminal on the Indicator
Shield Drain Wire
fd
u
8
0n
os
.w
mf
indicator indicator indicator FACP
Figure 5.2 EIA-485 in Conduit
earth
ground
earth
ground
Shield
EIA-485 Loop
in conduit
NOTE:
1. Power-limited 24 VDC power may be run in the same conduit as the EIA-485 wiring.
2. Twisted, shielded wire is recommended for the EIA-485 communications loop.
3. Each electrical backbox is connected to earth ground via the conduit.
4. Shield is connected to the FACP cabinet (earth ground) leaving and entering the FACP.