Measures For Long Distances; Measures For Short Distances - Siemens FDL241-9 Technical Manual

4.5.1
4.5.2
Building Technologies
Fire Safety

Measures for long distances

Long distances can be split into smaller ones for monitoring. Detectors positioned
opposite one another can however have a negative influence on one another. In
such a position, install a sufficiently large plate between the reflectors, such that it
is not possible for detectors to influence those opposite them.
FDL
Subdivision of a longer distance
To check whether two detectors are influencing one another, proceed as follows:
1. Commission the first detector and use the adjustment device to measure the
standardized signal value.
2. Commission the second detector.
3. Use the adjustment device to once again measure the standardized signal
value of the first detector.
- If the standardized signal value has not changed since the first
measurement, the two detectors are not influencing one another.
- If the standardized signal value has changed since the first measurement,
the two detectors are influencing one another. Install a larger plate between
the reflectors or take other suitable measures.
4. Completely cover the reflector and for each detector use the adjustment device
to measure the standardized signal value. Measure the signal value once when
the the detector opposite is switched on and once when it is switched off. The
two signal values measured must not differ.

Measures for short distances

In the case of a short detection distance between 5 and 10 m, you must also use a
short distance filter. The following filters are available:
Detection distance
5...8 m
7...10 m
Short distance filter
See also
 Accessories [➙ 30]
Detection distance and reflector selection
DLR
Filter
DLF1191-AB
DLF1191-AA
Planning
4
FDL
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2012-09-07