Pilz PSEN op2 Série Manuel D'utilisation page 63

PSEN op 2/4 Series Operating Manual
Also, under normal operating conditions, it must not be possible to
start the machine until the operator is outside the danger zone.
If it is impossible to install the light curtain in immediate proximity to the
danger zone, a second light curtain must be installed, aligned
horizontally, to exclude access from the side, as shown in Fig. 5b.
Fig. 5a Fig. 5b
If the installation position of the safety device still enables an operator
to access the danger zone without detection, an additional mechanical
barrier must be installed to prevent this happening.
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