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NFS2-640/E Operations Manual —
P/N 52743:F1 06/16/2011
Operation of the Control Panel
Operation of Special System Timers
3.13 Operation of Special System Timers
3.13.1 What are System Timers?
There are user-programmable time delays for three specific functions: the Auto Silence Timer, the
Alarm Verification Timer, and the Silence Inhibit Timer. Figure 3.3 shows a sample System
Function Selection screen with system timer settings. For instructions on changing system
functions, refer to the
NFS2-640 Programming Manual.
3.13.2 How to View System Timer Selections
You can use the Read Status Entry option (explained in Chapter 4) to view the current selection for
the System Timers. To do so, press the keys shown below in sequence:
The LCD display shows the current selections for System Functions, which includes the three
system timers.
Sample LCD display of a System Function screen with system timer selections:
Figure 3.3 Sample System Function Selection Screen
3.13.3 How System Timers Work
The control panel can operate with special system timers: Auto Silence Timer, Alarm Verification
Timer and Silence Inhibit Timer.
Auto Silence Timer
A timer that functions like pressing the
SIGNAL
SILENCE
key. When the Auto Silence Timer reaches
its programmed value (600-900 seconds), the control panel automatically shuts off all active
outputs programmed as silenceable.
Alarm Verification Timer
A timer that directs the control panel to ignore a fire alarm for a smoke detector, programmed for
Alarm Verification, while the Alarm Verification Timer is counting. Table 3.8 contains a summary
of how the Alarm Verification Timer works.
Silence Inhibit Timer
A timer that disables the
SIGNAL
SILENCE
key function and inhibits reset during countdown for the
programmed time (0-300 seconds) when a fire alarm occurs. A Silence Inhibit Timer starts at the
first fire alarm. Subsequent alarms will not restart the timer until the alarm condition is completely
resolved and a panel reset is performed.
Silence Inhibit Timer set to 180 seconds
Auto Silence Timer set to 600 seconds
Alarm Verification Timer set to 30 seconds
S I L I N H = 1 8 0 A U T O = 6 0 0 V E R I F Y = 3 0 U S A T I M E
T E R M = N A C - D L Y = Y L o c T B L I N K = 0 1 S T = 4 A C S = N
If
The control panel does this
A second fire alarm occurs while the
Alarm Verification Timer is counting
Ignores the Alarm Verification Timer
The Alarm Verification Timer elapses and
a fire alarm still exists
Activates the fire alarm
The Alarm Verification Timer expires and
a fire alarm no longer exists
Increments the Alarm Verification counter (up to 99)
for the device and returns to normal operation
Table 3.8 Alarm Verification Timer Operation
