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Document 50581 Rev A 12/9/96 P/N 50581:A
When the EIA-485 shield is in full conduit: The EIA-485 loop allows the FACP to
communicate with the LED-10N(s). The shield for the EIA-485 loop must be
connected to earth ground at the FACP, but must be left floating (no connection) at
the LED-10N if it is the first or only device on the EIA-485 loop. If a second LED-
10N is connected, the shield leaving the first LED-10N must be left floating. The
shield entering the second LED-10N must be connected to the Earth Ground
Terminal (TB1- 6 & 7) on the second LED-10N. If additional LED-10Ns are con-
nected, the shield leaving each LED-10N must be left floating and the shield
entering the following unit must be connected to the Earth Ground Terminal (TB1 -
6 & 7) on the LED-10N.
Caution! Do not allow the floating (no connection) end of the shield to contact the
conduit. The floating end should be insulated from earth ground.
Notes:
1) Power-limited 24 VDC regulated 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 LED-10N electrical backbox is connected to earth ground via the conduit.
4) Shield is connected to the FACP cabinet (earth ground) leaving the FACP.
TB2-1 (+) EIA-485
TB2-2 (-) EIA-485
TB1-6 Earth Ground (IN)
Connect the shield drain wire to the
Earth Ground Terminal on the LED-10N.
LED-10N Box
LED-10N
Shield Drain Wire
EIA-485 Shield Terminations
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