Mircom RAX-LCD, Installation And Wiring Manual

Page: 7 / 16

3
3.0 Wiring Instructions
The RS-485 wiring to the RAX-
LCD Display Module is
recommended to be twisted
shielded pair as shown in the
diagram to the right. The wire
gauge may be:
• 22 AWG up to 2000 ft.
• 20 AWG up to 4000 ft.
The RS-485 wiring from the
fire alarm control panel to
the annunciator(s) must be
point-to-point from the fire
alarm panel to the first
annunciator, then to the next
annunciator, and so on. No
star wiring or T-tapping is
allowed. Each RAX-LCD
Shared Display has a 120
ohm end-of-line resistor on
its RS-485 output terminals.
This is removed on all
except the last wired
module.
The 24 VDC field wiring needs to be of an appropriate gauge for the number of annunciators
and the total wiring run length. Use the
Current Drain for Battery Calculations on page 8 to
calculate the maximum current for all annunciators summed together.
24 VDC
INPUT
-
+
-
+
24 VDC
OUTPUT
24 VDC POWER FROM FIRE ALARM CONTROL
PANEL OR PREVIOUS ANNUNCIATOR
24 VDC POWER TO
NEXT ANNUNCIATOR
+
-
S
S
-
+
RS-485
INPUT
RS-485
OUTPUT
RS-485 TO NEXT ANNUNCIATOR
(TWISTED SHIELDED PAIR)
RS-485 FROM FIRE ALARM OR PREVIOUS
ANNUNCIATOR (TWISTED SHIELDED PAIR)
Figure 2 Wiring Diagram
RS-485 TERMINALS
24V POWER TERMINALS
ADDRESS DIP SWITCHES
SW1
P1 P2
ALARM
QUEUE SUPV.
QUEUE
TROUBLE
QUEUE
MONITOR
QUEUE
MGC Network
Fire Alarm Control System
System Normal
February 21, 2018 2:24PM
SIGNAL
SILENCE
GENERAL
ALARM
ACKNOW-
LEDGE
FIRE
DRILL
SYSTEM
RESET
LAMP
TEST
Figure 3 Annunciator Panel Connections