Approach
T
he 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 cal‐
culation 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 = 2,000 mm/s × T + 8 ×(d – 14 mm)
Where:
°
S = minimum dis
tance in millimeters (mm)
°
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)
The reach or approach speed is already included in the formula.
2. If the result S is ≤ 500 mm, then use the determined value as the minimum dis‐
t
ance.
3. If the result S is > 500 mm, then recalculate 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 mini‐
mum distance.
5. If the new value S is ≤ 500 mm, then use 500 mm.
Figure 9: Minimum distance to the hazardous point for orthogonal (rectangular) approach to the
pr
otective field
!
Protective field height
"
Hazardous point
§
Depending on the application and distance, persons must be prevented from standing
behind the protective device.
Example calculation
Mac
hine stopping time = 290 ms
Response time after interruption of the light path = 30 ms
Resolution of the safety light curtain = 30 mm
T = 290 ms +30 ms = 320 ms = 0.32 s
S = 2,000 mm/s × 0.32 s +8 × (30 mm –14 mm) = 768 mm
4 P
ROJECT PLANNING
26
O P E R A T I N G I N S T R U C T I O N S | deTec4 Ex 8022883/2019-03-07 | SICK
Subject to change without notice
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