20
107031-33-EN FR26 GLO 1101 Printed in France
Figure 3-3 Distance from Reflective Surfaces
100
200
300
400
500
600
700
800
900
-900
0
1
2
3
4
5
6
7
8
9
10
L
D
-800
-700
-600
-500
-400
-300
-200
-100
0
3.6
Mutual Interference or cross-talk
The FF-SYA Series light curtain is based upon an infrared transmission between an emitter unit and a receiver unit. It is a safety
requirement of the IEC/EN 61496-2 standard that if a receiver R2 receives two signals transmitted by two different emitters E1
and E2, the receiver R2 must turn to the alarm state. This happens if the receiver R2 is within the 2,5° beam aperture angle and
within the nominal scanning range of the second emitter E1, and the cross-talk detection indicator flickers to warn the installer.
MUTUAL INTERFERENCE OR CROSS-TALK
Reception of two infrared emissions will maintain the light curtain in a lockout condition. To go back to normal operation, switch
the power off and eliminate the interferences by reversing systems emitting orientation or by using opaque screen, or by
adjusting the adequate emission power regarding the application. Then, restore the power.
Figure 3-4 Mutual Interferences between two light curtain sets
R3
R2
R1
alarm
test
E
1
E
1
R
1
R
2
E
2
ON
OFF
R
2
A selector switch is available on the emitter unit for the selection of the adequate emission power. It can be used to prevent this
cross-talk phenomenon by decreasing the nominal scanning range.
F
SYA1
9
F
SYA2
0
F
SYA2
1
Minimum distance to reflective surface (in mm)
Distance L between emitter and receiver
(optical axis)
F
SYA1
8