Example calculation
Mac
hine stopping time = 290 ms
Response time after interruption of the light path = 30 ms
Resolution of the safety light curtain = 14 mm
T = 290 ms + 30 ms = 320 ms = 0.32 s
S = 2,000 mm/s × 0.32 s + 8 × (14 mm – 14 mm) = 640 mm
S > 500 mm, therefore:
S = 1,600 mm/s × 0.32 s + 8 × (14 mm – 14 mm) = 512 mm
4.3.2.2 Taking reach over into account
In accordance with ISO 13855, it must not be possible to defeat the ESPE. If access to
t
he hazardous area by reaching over a protective field cannot be prevented, the height
of the protective field and minimum distance of the ESPE must be determined. This is
done by comparing the calculated values based on the possible detection of limbs or
body parts with the values resulting from reaching over the protective field. The greater
value resulting from this comparison must be used.
Figure 12: Representation of the accessibility of electro-sensitive protective device by reaching
o
ver. Left: Protective field that cannot be reached over. Right: Protective field that can be reached
over.
4.3.3 Minimum distance to reflective surfaces
Overview
T
he light beams from the sender may be deflected by reflective surfaces and dispersive
media. This may prevent an object from being detected.
Therefore, all reflective surfaces and objects (e.g. material bins, machine table, etc.)
must maintain a minimum distance (a) from the protective field. This minimum dis‐
tance (a) must be maintained on all sides of the protective field. This applies in
horizontal, vertical and diagonal directions as well as at the end of the safety light
curtain. The same area must be free of dispersive media (e.g., dust, fog, or smoke).
The minimum distance (a) depends on the distance (D) between sender and receiver
(protective field width).
4 P
ROJECT PLANNING
30
O P E R A T I N G I N S T R U C T I O N S | deTec4 Ex II 3GD 8023872/18YZ/2021-01-14 | SICK
Subject to change without notice
To Next Page
Loading...
