PI - 34.85
Product Information Linear Smoke Detector Fireray 50/100RV
601-F.01U.002.705
A1.en / 29.12.2004
ST-FIR/ PRM1/ zab
Seite 6 von 22
5.
Functional Description
The transmitter emits an infrared light beam (880 nm) that is focused through a lens
and invisible. The light beam is reflected by 180
by the prism reflector mounted
opposite and returned to the transmitter/receiver combination.
If the IR beam is obscured by smoke and the signal received drops below the selected
threshold value for 10 s, the Fireray triggers a fire alarm and the alarm relay closes.
The activation threshold can be adjusted to the environmental conditions. Settings
25% (sensitive), 35%, and 50% (non - sensitive) are possible.
The alarm relay has two operating modes:
With Auto Reset, the alarm relay releases again if the volume of smoke drops below
the selected alarm threshold for at least 5 s.
In Alarm memory mode, the relay remains active until it is reset. To reset, power is
dropped to the detector for at least 5s.
Slow changes to the operating states (e.g. aging of the components, contamination
of the lenses, etc.) do not cause false alarms; instead, they are balanced out by the
automatic gain control. The state of the system is compared with a default reference
value every 15 minutes and in case of deviations, compensated automatically up to
0.7 dB/h. If the readjustment limit is reached, any further signal decay will trigger a
«malfunction» (DIP switch 2 = on) or an «alarm» (DIP switch 2 = off).
If the IR beam is obscured for at least 10 seconds by more than 90% with a sharp signal
increase, the fault relay switches. The cause can be a blocking of the beam path,
detector misalignment, blocking of the reflector, etc. After eliminating the cause of the
malfunction, the fault relay is reset and the detector is reset automatically into the
detection - ready state after 5 seconds. The malfunction must be reset at the control
unit.
The detector has an alarm output in the form of a potential free, latching dry contact.
