NFS2-640/E Operations Manual —
P/N 52743:F1 06/16/2011
25
Pre-Alarm Warning Mode of Operation
Operation of the Control Panel
•
Sends a Pre-Alarm message to the LCD display, History buffer and installed printers, FDU-80
annunciators, and CRT-2s
•
Displays a
PREALARM
status banner, the Type Code of the detector, and the Pre-Alarm level
(Alert or Action) on the LCD display, along with information specific to the device as shown
in Figure 3.9.
3.7.2 How to Respond to a Pre-Alarm Warning
Pre-Alarm Alert and Action Levels
The Pre-Alarm function is a programmable option which determines the system’s response to
real-time detector sensing values above the programmed setting. Use the Pre-Alarm function if you
want to get an early warning of incipient or potential fire conditions. The Pre-Alarm function
provides one of two levels of Pre-Alarm as follows:
•
Alert – a non-latching condition that causes a Pre-Alarm when a detector reaches the
programmed Pre-Alarm level.
•
Action – a latching condition that causes a Pre-Alarm when a detector reaches the programmed
Pre-Alarm level.
Responding to a Pre-Alarm Warning
The Pre-Alarm screen display is the same for both alert and action conditions. Following is a
sample screen for a Pre-Alarm message.
Figure 3.9 Sample of an Alert Pre-Alarm Message
An Alert Pre-Alarm automatically restores to normal when the detector sensitivity, programmable
to one of nine settings, drops below the programmed Alert level. Zone F09 automatically clears
when no Pre-Alarm conditions exist.
An Action Pre-Alarm latches until you reset the system - even if the detector sensitivity drops
below the Action level. Zone F09 activates - but Zone Z00 (general alarm) and the trouble and
alarm relays do not activate. The fifth zone programmed, not the first four, in the detector’s CBE
activates. A subsequent alarm condition for this detector clears the Action indication from the LCD
display.
Interpreting Pre-Alarm Type Codes
The Type Code that displays in the Pre-Alarm warning indicates the function of the point that
initiates the Pre-Alarm warning. Refer to the Detectors section of Table 3.1 for the Type Codes that
can appear in a Pre-Alarm warning, and for descriptions of those Type Codes.
NOTE:
For detailed information on Pre-Alarm applications, refer to the
NFS2-640 Programming
Manual
.
Detector programmed for a Pre-Alarm level of 4
Shows the detector has reached 55% of the
programmed Pre-Alarm level. The 55% is a
real-time display and tracks smoke levels
Status banner
Type Code
P R E A L M S M O K E ( P H O T O ) I N T E N S I V E C A R E U N I T
E A S T E R N W I N G 0 5 5 % / 4 0 3 : 2 0 P 0 4 1 5 0 8 1 D 1 4 7
Custom descriptor for
this device location
Device address
Time and date of trouble
Extended 12
character
custom label
