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Fire & Security Products
Siemens Building Technologies Group 06.2001
6 Emergency operation
If the PolyRex detector DOT1151-Ex can no longer be periodically addressed, for example
due to a µP failure in the control unit, the detectors switch automatically to emergency op-
eration. In the event of a fire this detector can still trigger a collective alarm.
7 Response characteristics of the
detector
The PolyRex detector DOT1151-Ex is equipped with efficient algorithms for discriminating
between true fires and deceptive phenomena. To signal a danger level the detector does
not simply respond to a reading above a «response threshold», but rather tracks the smoke
density pattern over a longer period of time and evaluates it with appropriate algorithms.
The software parameters determine the response behavior of the detectors. They are de-
pendent on the risk prevailing at the installation site (on the selected parameter set) and on
the activated operating mode (day, night, special [renovation], test and switched off).
The current operating mode is signalled to the detectors by the control unit in intervals of
approx. 3 seconds.
The algorithms contain, for example, filters for suppressing transient interference vari-
ables. Slow changes caused by contamination are compensated by the automatic digital
compensation circuit. This extremely slow compensation ensures that also slowly develop-
ing fires are reliably detected.
8 Environmental influences
8.1 Influence of the ambient air temperature
The smoke sensitivity of the PolyRex detector DOT1151-Ex typically changes typical
±10% across the entire operating temperature range.
8.2 Other influencing variables
The PolyRex detector DOT1151-Ex is resistant to ambient light, air drafts and other
changes within the specified data.
The influence of air drafts with fast and large temperature fluctuations depends on the se-
lected parameter set.
9 Application
9.1 Compatibility
Fire detection system: S11 AlgoRex
Control unit: CC11 (E3M171)
Base: DB1151A
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