8 MultiSensor Detector
8.1 Operating Principles:
The XP95 multisensor detector contains an optical smoke sensor
and a thermistor temperature sensor whose outputs are combined
to give the final analogue value.
The multisensor construction is similar to that of the optical detector
but uses a different lid and optical mouldings to accommodate the
thermistor temperature sensor. The sectional view (Fig.15) shows
the arrangement of the optical chamber and thermistor.
The signals from the optical smoke sensing element and the
temperature sensor are independent, and represent the smoke level
and the air temperature respectively in the vicinity of the detector. The detector’s microcontroller processes
the two signals. The temperature signal processing extracts only rate of rise information for combination with
the optical signal. The detector will not respond to a slow temperature increase - even if the temperature
reaches a high level. A large sudden change in temperature can, however, cause an alarm without the
presence of smoke, if sustained for 20 seconds.
The processing algorithms in the multisensor incorporate drift compensation. The control panel must not
have a drift compensation algorithm enabled.
The sensitivity of the detector is considered the optimum for most general applications since it offers good
response to both smouldering and flaming fires.
Note: in situ testing of the multisensor should be carried out as for smoke detectors.
Figure 15 – Sectional View – XP95 Multisensor Detector
8.2 Product Codes
Product Description LPCB (CEA4021) SAI Global (AS7240-15)
XP95 Multisensor Detector
55000-885AMP 4106-2004
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