ZX Fire Alarm Control Panels
MORLEY-IAS
Installation Manual
Document No. 996-174-000-1, Revision: 01
Page 23
3.4.9 RS485 Wiring Arrangements
EN54
!
EN54-2 12.5
Integrity of
transmission paths:
The network does
not provide the
required
transmission path
integrity.
The following diagrams show the wiring arrangements for ‘daisy
chain’ and ‘loop’ installations of the panel network and peripheral
data bus interfaces.
Refer to Section 3.4.13 for a list of recommended cables.
3.4.9.1
Daisy Chain Style Installation
Form the peripheral or
panel RS485 link by taking
wires from the A and B
terminals at one side of
the interface board
connector to the A and B
terminals of the next
device on the link.
Continue wiring to all the
units to be connected to
the link – connecting A to
A and B to B.
EOL
EOL
B A B A
Install EOL (150R, 0.5W
minimum, P/N 170-073-
151) resistors in the spare
terminals in both the first
and last units on the link.
Figure 21 – Typical RS485 – ‘Daisy Chain’ Wiring
The maximum allowed
length of the link is 1.2km
(4000’).
3.4.9.2
Loop Style Installation
Form the peripheral or panel
RS485 link by taking wires
from the A and B terminals at
one side of the interface board
connector to the A and B
terminals of the next device on
the link.
B A B A
Continue wiring to all the units
to be connected to the link –
connecting A to A and B to B.
+
Install return wiring from the
spare terminals on the last unit
to the spare terminals on the
first unit.
Figure 22 – Typical RS485 – ‘Loop’ Wiring
The maximum allowed length
of the complete loop is 1.2km
(4000’).
