Document No: LT0255
F3200/NDU AS4428.1 Installation Manual
Applications
Issue 1.22
5 July 2016
Page 6-7
6.1.4
LEDS
The 3 LEDs may be controlled directly from the switch; driven off 3 open collector (O/C)
outputs or driven off 2 O/Cs with a Zener diode as shown in Fig 6.1.6. Note that where the
FIP has a number of detector circuits, the open collector outputs associated with these AZCs
may be used for driving the AS1668 LEDs and so it doesn't matter if the AS1668 panel
requires more open collectors than circuits.
+VBF
─┬─
│ 3K3 ┌──┐
RUN ├───────>├────█████────────┤ │ OC1
│ Red └──┘
│ 3K3 ┌──┐
FAULT ├───────>├────█████────────┤ │ OC2
│ Yellow └──┘
│ 3K3 ┌──┐
STOP └───────>├────█████────────┤ │ OC3
Green └──┘
A.
THREE OPEN COLLECTOR O/PS PER FAN.
+VBF
─┬─
│ 3k3 RUN ┌──┐
├────█████───┬───>├────────┤ │ OC1
│ │ Red └──┘
│ STOP
Green
│ ╒╧╕
│ │ │5V6 ZENER
│ └┬┘
│ ─┴─
│ 3K3 0V FAULT ┌──┐
└────█████───────>├────────┤ │ OC2
Yellow └──┘
B.
TWO OPEN COLLECTOR O/PS PER FAN.
For other LEDs (e.g. Chrome Bezel LEDs) a lower value (higher current) resistor may be
required.
FIG 6.1.6
WIRING OF FAN CONTROL LEDS
Note that the logic required for the LEDs in Option B is as follows:
LEDs
OUTPUTS
RUN
FAULT
STOPPED
OC1
OC2
off
off
on
off
off
on
x
off
on
x
x
on
x
x
on
Where x = off or on (don't care).
