Further topics
•
4.3.2.1
Calculating minimum distance from the hazardous point
Important information
DANGER
Minimum distance from the hazardous point is too small
The dangerous state of the machine may not be stopped or not be stopped in a timely
manner due to a minimum distance that is too small.
b
Calculate the minimum distances for the machine in which the safety light curtain
is integrated.
b
When mounting the safety light curtain, observe the minimum distance.
NOTE
If the safety light curtain is configured with a reduced resolution, then the minimum
distance must be calculated according to the effective resolution in accordance with
ISO 13855.
If the effective resolution is > 40 mm, a different formula may have to be used for the
calculation of the minimum distance.
NOTE
If the Smart Box Detection function is configured on the safety light curtain, then a
different formula must be used to calculate the minimum distance,
distance to the hazardous point with Smart Box Detection", page 51
.
Approach
The example shows the calculation of the minimum distance in accordance with ISO
13855 for an orthogonal (right-angled) approach to the protective field. A different
calculation may be required depending on the application and the ambient conditions
(e.g., for a protective field parallel to or at any angle to the direction of approach or an
indirect approach).
1.
First, calculate S using the following formula:
S = (K × T) + 8 × (d – 14 mm)
Where:
°
S = minimum distance in millimeters (mm)
°
K = approach speed (stepping and/or gripping speed) of a person or a body
part (mm/s), e.g. 2,000 mm/s
°
T = machine stopping time + response time of the protective device after
interruption in the light path in seconds (s)
°
d = resolution of the safety light curtain in millimeters (mm)
2.
If the result S is ≤ 500 mm, then use the determined value as the minimum
distance.
3.
If the result S is > 500 mm, then recalculate S with an approach speed of 1,600
mm/s as follows:
S = 1,600 mm/s × T +8 × (d – 14 mm)
4.
If the new value S is > 500 mm, then use the newly determined value as the
minimum distance.
5.
If the new value S is ≤ 500 mm, then use 500 mm.
PROJECT PLANNING
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8021645/1EB0/2022-04-28 | SICK
O P E R A T I N G I N S T R U C T I O N S | deTec4
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Subject to change without notice
