System Description; System Operation - FFE Fireray 50RU Technical Bulletin

1. System Description.

Fireray 50/100RU Detector comprises a Transmitter and Receiver contained within one enclosure.
The Detector installs to the building fabric between 1 and 2 feet from the ceiling.
The Transmitter emits an invisible infrared light beam that is reflected via a prism mounted directly
opposite and with a clear line of sight. The reflected infrared light is detected by the Receiver and
analysed.
The Detector has maximum lateral detection of 30 feet either side of the beam.

2. System Operation.

Smoke in the beam path will reduce the received infrared light proportionally to the density of the smoke.
The Detector analyses this attenuation or obscuration of light and acts accordingly.
2.1. Alarm Threshold.
Alarm thresholds of 25%, 35%, and 50% can be selected to suit the environment, where 25% is the most
sensitive. If the received infrared signal reduces to below the selected threshold and is present for
approximately 10 seconds, the fire relay is activated.
2.2. Fire Alarm.
There are two modes to the operation of the fire relay. Auto reset mode will reset the fire relay 5 seconds
after the received infrared signal has recovered to a level above the Alarm threshold. Latching mode
holds the fire relay active indefinitely after an Alarm condition has occurred.
To clear the latched mode power must be removed from the Detector for a minimum of 5 seconds.
2.3. Trouble Alarm.
If the infrared beam is obscured rapidly to a level of 90% or greater for approximately 10 seconds the
Trouble relay is activated. This condition can be entered in a number of ways, for example, an object
being placed in the beam path, transmitter failure, loss of the prism, or sudden misalignment of the
Detector.
The Trouble relay will reset within 2 seconds of the condition being rectified.
2.4. Automatic Gain Control.
The Detector monitors long term degradation of signal strength caused by component ageing or build up
of dirt on optical surfaces. This operates by comparing the received infrared signal against a standard
every 15 minutes; differences of less than 0.7dB/Hour are corrected automatically.
showing AGC fault, the detector will still operate correctly indicating Alarm and Trouble as normal.
2.5. Low Level Controller Test (Optional Extra).
The detector has a 2-pin port to allow the use of an optional extra Low Level Control unit (see fig.4). The
Low Level Controller will simulate an Alarm situation and cause the detector to go into an 'Alarm'
condition.
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When the detector is