6
INSTALLING BEAM DETECTORS
Installation of interface
The interface should be positioned so that it is easily
accessible and such that the cable connecting the
interface to the receiver is not more than 100m long.
The use of multi-core cable for connecting two or more
receivers is
not
permitted. Care should be taken that
this cable is routed away from building electrical cables
Setting the obscuration level
Set the interface to one of the four obscuration settings
shown below.
and any switchgear. Ensure that the cable used has
adequate mechanical protection.
Connect cables as shown in Fig 3 and set the ad-
dress at the DIL switch on the front of the interface as
described opposite.
Setting the ‘total obscuration’ signal
Total obscuration is de
fi
ned as obscuration of the beam
to greater than 93% in 8–10 seconds. The interface
must be set so that either a ‘
fi
re’ or a ‘fault’ signal is
generated when this occurs. This is done by moving
segment 3 of the sensitivity switch (Fig 4) to ‘0’ for
a ‘fault’ signal or to ‘1’ for a ‘
fi
re’ signal. The factory
default setting is ‘fault’.
Issue No
Fig 4
Front view of interface
Fig 3
Interface wiring diagram
Colour Terminal
Red A
Black B
Yellow C
Blue D
NOTE: The beam detector is polarity sensitive.
XP95/Discovery
Loop
rear view
+
–
remote
fire LED
}
}
Loop +ve
A
B
C
D
From receiver
Maximum cable
length 100m
Loop –ve
+
–
Obscuration level in %
Typical application
25
Of
fi
ces, small premises,
non-smoking clean areas,
eg, museums, theatres
35
Factories, warehouses
50
Hostile environments, eg,
mills, foundries
65
Retro mode operation
only
Table 1
Obscuration levels
