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107031-33-EN FR26 GLO 1101 Printed in France
3.8.4
Vertical Mounting / Side by Side Installation
MUTUAL INTERFERENCE OR CROSS-TALK
When two or more light curtain systems are installed on adjacent machines, optical interference may occur if two units are within
the field of view. Mutual interference between light curtains can be eliminated by reversing systems emitting orientation, or by
using opaque screens, or by adjusting the adequate emission power regarding the application. A selector switch is available on
the emitter unit for this purpose. Reception of 2 infrared emissions will maintain the light curtain in a lockout condition. To go
back to normal operation, switch off and on the light curtain power.
The FF-SYA light curtain is based upon an infrared transmission between an emitter unit and a receiver unit. It is a requirement
of the IEC/EN 61496-2 standard that if a receiver receives two signals transmitted by two different emitters, this receiver must
turn to the alarm state for safety reasons. This happens if the considered receiver is within the 2,5° beam aperture angle and
within the nominal scanning range of a second emitter, and when the cross-talk detection indicator flickers to warn the installer.
Figure 3-15 Side by side installation of two light curtains
E
m
itte
r 1
R
ecei
ver
1
E
m
itte
r 2
R
ecei
ver
2
or
E
m
itte
r 1
R
ecei
ver
1
E
m
itte
r 2
R
ecei
ver
2
P
o
ssi
b
le o
p
a
q
u
e
scr
een
Eliminating mutual interferences by reversing systems
emission orientation.
Eliminating mutual interferences by using an opaque
screen or by adjusting the emitter 1 emission power
(see 3.6 Mutual Interference or cross-talk)
Figure 3-16 Side by side installation of more than two light curtains
E
m
itte
r 1
R
ecei
ver
1
E
m
itte
r 2
R
ecei
ver
2
E
m
itte
r 3
R
ecei
ver
3
E
m
itte
r 4
R
ecei
ver
4
WORK STATION 4
WORK STATION 3
WORK STATION 2
WORK STATION 1
P
o
ssi
b
le o
p
aq
u
e scr
een
If the beams of two adjacent light curtains are reversed, no interference will occur between these two light curtains. If more than
two light curtains are installed side by side, then some of them may interfere together. In the above example, Receivers 2 and 3
may respectively receive a signal from the Emitters 4 and 1. An opaque screen can be used between emitter 2 and emitter 3 to
solve this mutual interference problem. However, switches available on emitters 4 and 1 may be used to reduce the effective
scanning range and solve this problem in a smart manner (see 3.6 Mutual Interference or cross-talk).
F
SYA3
5
F
SYA3
6
F
SYA3
7