Section Five: E: E: E: E: Eia-485 Shield Section Fiv; Eia-485 Shield T T T T T Er Er Er Er Erminations Eia-485 Shield Minations Minations; When The Eia-485 Shield Is Not In Conduit - Fire-Lite Alarms LED-10 Manual

Section Fiv Section Five: e: e: e: e: EIA-485 Shield Section Fiv
Section Fiv Section Fiv
The EIA-485 circuit must be wired using a twisted-shielded pair cable having a charac-
teristic impedance of 120 ohms, +/- 20%. Do not run cable adjacent to, or in the same
conduit as, 120-volt AC service, noisy electrical circuits that are powering mechanical
bells or horns, audio circuits above 25 V
Note: Note:
Note: To ensure static (ESD - electrostatic discharge) protection, all enclosures, Note: Note:
including the LED-10 electrical box, must be connected to earth ground! Never use the
EIA-485 shield for this purpose. The EIA-485 shield is for radiated noise emission
protection (RFI, EMI). Refer to the following figures.
The EIA-485 shield should be terminated as follows:

When the EIA-485 shield is not in conduit:

When the EIA-485 shield is not in conduit: When the EIA-485 shield is not in conduit: When the EIA-485 shield is not in conduit: When the EIA-485 shield is not in conduit: The EIA-485 loop allows the FACP to
communicate with the LED-10(s). The shield for the EIA-485 loop must be con-
nected to earth ground at the FACP but must be left floating (no connection) at the
LED-10 if it is the first or only device on the EIA-485 loop. If a second LED-10 is
connected, the shield leaving the first LED-10 must be left floating. The shield
entering the second LED-10 must be connected to the 3-gang box or Earth Ground
terminal (TB1-6 & 7) on the second LED-10. If additional LED-10s are connected,
the shield leaving each enclosure must be left floating and the shield entering each
must be connected to the 3-gang box or the Earth Ground Terminal (TB1-6 & 7) on
the LED-10.
Connect the drain wire to the
outside of the MS-5210UD cabinet
via a BX-type connector.
Shield Drain Wire
18 18 18
18 18
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EIA-485 Shield T T T T T er er er er erminations EIA-485 Shield EIA-485 Shield
EIA-485 Shield
RMS
FACP Backbox FACP Backbox FACP Backbox
FACP Backbox FACP Backbox
Document 50400
firealarmresources.com
minations minations minations
minations
, motor control circuits, or SCR power circuits
Rev A 5/15/96 P/N 50400:A
(+) EIA-485 (+) EIA-485
(+) EIA-485 (+) EIA-485 (+) EIA-485
(-) EIA-485 (-) EIA-485 (-) EIA-485
(-) EIA-485 (-) EIA-485
FACP FACP
FACP FACP FACP