OPERATION
30
5.4
ALARM SIGNALLING
The FV300 detector has a number of external interfaces. An alarm condition is signalled on all of
these interfaces as follows:
Alarm relay:
The alarm relay will close.
4-20mA:
The current (source or sink) becomes 17mA
Modbus:
The alarm bit is set in the status register and is available at the next read of the
unit.
Video:
An alarm banner will be superimposed on the CCTV image along with a target
showing the location of the alarm.
Each interface will remain activated until the reason for the alarm has cleared (non-latching mode)
when it will turn off. In latching mode the detector will also need to be reset, see below.
5.5
PRE-ALARM SIGNALLING
The detector enters a pre-alarm state when it detects a source within the field of view that has not
yet reached the alarm threshold. The source may be worthy of investigation.
The FV300 detector has a number of external interfaces. A pre-alarm condition is signalled on
some of these interfaces as follows:
Alarm relay:
No change, the alarm relay will remain open.
4-20mA:
The current (source or sink) becomes 11.5mA
Modbus:
The pre-alarm bit is set in the status register and is available at the next read
of the unit.
Video: No
change.
The pre-alarm condition will escalate into a full alarm if the source is determined to be a fire. Or
it will clear if the source is removed.
5.6
FAULT AND OPM INDICATION
The fault (yellow) LED will illuminate when the detector has detected a hardware fault. It will
remain illuminated until the reason for the fault has cleared (non-latching mode) when it will turn
off. In latching mode the detector will also need to be reset, see 5.9.
If the regular OPM test determines that the window is dirty then the fault (yellow) LED will flash
approx.(1 second, 1 second off). If the window is found to be completely obscured it is treated as
a hardware fault and the fault LED is illuminated.
The fault LED is located in the camera window, see Fig. 22.
5.7
SERVICE MODE INDICATION
The detector is put into the Service Mode when it is connected to a PC for configuration or
diagnostics. When in this mode, the fault (yellow) LED wil flash slowly (2 seconds on, 2 seconds
off).
Note:
In Service Mode the detector is disabled and will not detect a fire.
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