Electrical Connections
EIA-485 Connections
23
Document 53244 Rev. A 03/14/08 P/N 53244:A
4.2
EIA-485 Connections
Notes:
1. All connections are power-limited and supervised
2. A maximum of 32 LCD-80FC indicators may be connected to
this circuit
3. 6,000 feet (1,800 m) maximum distance @ 18 AWG (0.75 mm
2
)
between the FACP and first LCD-80FC, between each LCD-
80FC and return to the FACP from last LCD-80FC
4. Use overall foil/braided-shielded twisted pair cable suitable for
EIA-485 applications (refer to “EIA-485 Shield Termination” on
page 24, for shield termination information). Six conductor
overall shielded wire may be used for the four EIA-485 wires
and the two power wires. It is, however, strongly recommended
that the power and communication wires be separate whenever
possible
5. Ferrite Core P/N FBD-1 is required to meet FCC Part 15 require-
ments if the EIA-485 wiring is not in conduit
6. The EIA-485 circuit is rated at 5.5 VDC maximum and 60 mA
maximum
7. The LCD-80FC Indicator has resistors built into the circuit board
at the In (Terminals 2 & 4) and the Out (Terminals 1 & 3) for
impedance matching. There is no need for the installer to add
impedance matching resistors
8. Enable FACP communication with the LCD-80FC in the FACP
programming if appropriate (refer to FACP manual)
4 3 2 1
7 6 5 4 3 2 1
1 2 3 4 5 6 7 8
Figure 4-2: EIA-485 Connection
P2
P1
+ EIA-485 OUT
+ EIA-485 IN
- EIA-485 OUT
- EIA-485 IN
in from FACP
Out to next LCD-80FC or return
to host FACP if last or only indi-
cator on the line
Ferrite Core P/N FBD-1 is required (see note 5)
FDU80
B
ds
c
d
r
LCD-80FC
