NFS-320/E/C, NFS-320SYS/E Operations Manual — P/N 52747:E1 06/16/2011 27
Pre-Alarm Warning Mode of Operation Operation of the Control Panel
3.8.2 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 3.11 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 NFS-320 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
PREALM SMOKE(PHOTO) INTENSIVE CARE UNIT
EASTERN WING 055%/4 03:20P 011511 1D147
Custom descriptor for
this device location
Device address
Time and date of trouble
Extended 12
character
custom label
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