TYPE 4208 “F” PANEL AND “G” PANEL
SUPERVISED DC SIGNAL PANELS
INTRODUCTION
The “F” panel and the “G” panel supervise each
alarm signaling device and its associated wiring.
The “G” panel has a McCulloh circuit which in-
sures that the alarm signals will sound even if one
The panels will automatically provide standby bat-
tery operation if the normal AC power should fail.
of the alarm circuit wires is defective.
TYPE 4208 “F”
SUPERVISED DC SIGNAL PANEL
CIRCUIT OPERATION (FIG. 10)
POWER FAILURE CIRCUIT
Operation of the “F” panel and “G” panel pow-
er supply is similar to the operation of the “N”
panel power supply.
Refer to “N” panel Power
Failure Condition (Page 16) for detailed circuit
description.
terminals 3 of the signaling devices to “F” panel
terminal 4. (Current flow through the 3-4 terminal
diodes is not sufficient to keep relay K2 energized
if an open developed in ,one of the alarm signaling
devices.) From “F” panel terminal 4 current flows
through contacts K4A (8&5), diode Dl, relay K3
(energizing K3) to terminal +BAT.
SUPERVISION CIRCUIT
Trouble Condition
Normal Operation
During normal operation each alarm signaling de-
vice is supervised as current flows from terminal
-24VDC through fuse F3, contacts K4B (4&l), ter-
minal 5, the building wiring, terminals 2 of the
signaling devices, to terminal 1 of the last device
where the current flow splits into two paths.
One path is through the signaling devices via ter-
minals 1 and 4 to “F” panel terminal 3. From ter-
minal 3, current flows through the K3A con-
tacts, supervision relay K2 (energizing K2) to ter-
minal +BAT.
If an open occurs in any of the alarm signaling
devices, supervisory relay K2 de-energizes, its con-
tacts transfer and -24VDC is applied from “F”
panel terminal 7 to terminal 5 of the “A” panel
which causes a “trouble” condition in the “A” pan-
el. (Refer to “A” panel Trouble Condition for de-
tailed circuit description.) Current flows from ter-
minal -24VDC through terminal 6, contacts K2A
(l&4), terminal 7 to “A” panel terminal 5.
The other path is through the EOL resistor to all
If an open occurs in the alarm circuit wiring, re-
lay K3 de-energizes and its K3A contacts open.
When the K3A contacts transfer, relay K2 de-ener-
gizes and causes a “trouble” condition in the “A,’
panel. (Refer to the preceding paragraph for a de-
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