MAN1544-5
35
6
Agent Release
Fit EOL Termination
Link 1 if Last Module
on Comms Bus
In
Out
C
N
1
C
N
2
RS485 Control
/ 27VDC
Comms In
Top Module & PCB
Securing Clips
RS485 Control
/ 27VDC
Comms Out
TB4
LK2
+
MANUAL
RELEASE
INHIBIT
SWITCH MON
DISABLE
LK1
LINK
TERMINATOR
EOL
1
2
3
4
ON
S W 2
ADDRESS
SWITCH
10K
EOL
MCP
AGENT RELEASE
Figure 15: AS4428 Agent Control Card
6.1
Controls
It is a requirement that control be secured from unauthorised use. A keyswitch has
therefore been included in the control process.
The FCP goes into service mode when the keyswitch is switched to SERVICE INHIBIT. This results in the
selected agent activation circuit being electrically isolated and a Common Isolate condition being indicated
at the FACP. This condition can also be confirmed through the Status Menu. To remove the key it is
necessary for the switch to be in the
OFF
position.
Pressing Select toggles the selection of either the Main or Reserve release agent. Selection is
indicated by the Main and Reserve Agent LED’s
Pressing the Agent Inhibit switch will inhibit the gas from release in either the Manual or
Automatic mode. The Agent Inhibit switch has an internal lamp fitted with yellow lens and is illuminated
when the Inhibit switch is activated at the FACP or any of the LCS’s. To prevent acc
idental operation this
switch has a hinged clear plastic cover that has to be raised to access the switch.
Manual Release
The ARC has provision to connect a front panel MCP. When the MCP is activated
–
a manual release
sequence of the agent is started.
The MCP is fitted with a protective flap
–
hence two actions are required to release the agent
–
that is lift
the flap and activate the MCP.
