10
EN
2.3.2 Parallel Approach to the Safety Field
If this safety concept is used, the height of the safety field (H) may not be any greater than 1000 mm. If H is
greater than 300 mm (or 200 mm for non-industrial applications, e.g. if children are present), one runs the
risk of inadvertent, undetected access from underneath the safety field. This must be taken into consider-
ation during risk analysis.
H = Height of the safety field above the reference level
C = Margin for penetration into the danger zone before the safety device is tripped (never < 850) = 1200 mm -
0.4×H
K = 1600 mm per second
S = K×(t1+t2)+C(1200 mm - 0,4×H)
Direction of
Approach
S = Minimum safety clearance
H = Height of the safety field
2.4 Minimum Clearance to Reflective Surfaces
If reflective surfaces are located within the aperture angle between the transmitter and the receiver, reflection may
result which could cause an obstruction to go undetected. For this reason, a minimum clearance (m) between
reflective objects and the optical axis must be maintained.
Beam angles are taken from the IEC 61496-2 standard. They represent worst case values. Actual values are lower.
Danger Zone
Reflective
Object
Central Beam
Transmitter
Receiver
Light Beam
Obstructed
m = tan
a
× (distance from transmitter to receiver
a
= Opening Angle of Emitter and Receiver Optic
a
= ±5°