NFS2-640 Operations P/N 52743:L4 06/10/19 31
Pre-Alarm Warning Mode of Operation Operation of the Control Panel
3.8 Pre-Alarm Warning Mode of Operation
3.8.1 How the Control Panel Indicates a Pre-Alarm Warning
The control panel activates a Pre-Alarm Warning if a detector exceeds the programmed Pre-Alarm
Alert or Action level. When a detector activates a Pre-Alarm, the control panel does the following:
• Pulses the panel sounder
• Flashes the
PRE-ALARM LED
• Activates the Pre-Alarm zone (F9)
• 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 3.13.
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 pro-
vides 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 sam-
ple screen for a Pre-Alarm message.
Figure 3.13 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.
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
PREALM SMOKE(PHOTO) INTENSIVE CARE UNIT
EASTERN WING 055%/4 03:20P 041515 1D147
Custom descriptor for
this device location
Device address
Time and date of trouble
Extended 12
character
custom label
To Next Page
Loading...
