schmersal SLC 410 B Instructions De Montage Et De Raccordement page 64

USE OF DEFLECTION MIRRORS
In order to protect or control areas that can be accessed from more than one side, in addition
to the Emitter and Receiver, one or more deflection mirrors can be installed.
These mirrors enable the optical beams generated by the Emitter to be deviated on one or
more sides.
If the beams emitted by the Emitter must be deviated by 90°, the perpendicular to the
surface of the mirror must form an angle of 45° with the direction of the beams.
The following figure illustrates an application in which two deviation mirrors are used to
provide a U-shaped protection.
The following rules should be taken into consideration when using deviation mirrors:
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Place the mirrors so as to ensure compliance with the minimum safety distance
S (Figure 24) on each side from which the danger zone can be accessed.
The working distance (range) is given by the sum of the lengths of all the sides
that give access to the protected area. (Remember that for each mirror used
the maximum working range between the Emitter and the Receiver is
reduced by 15%).
During installation, take great care to avoid twisting along the longitudinal axis
of the mirror.
Make sure, by standing near to and on the axis of the Receiver, that the entire
outline of the Emitter is visible on the first mirror.
The use of more than three deviation mirrors is not recommended.
Figure 24