Wieland SLC Series Operating Instructions Manual page 22

Calculation of safety distance S
S [mm]
RT
K [mm/s] = Approach speed for access guarding with approach direction orthogonal to
T [s]
t [s]
a
t [s]
i
t [s]
m
C [mm]
RT
Calculation example
Access to a robot with a stopping time of 250 ms is to be safeguarded with a safety light cur-
tain with 90 mm of resolution and 1500 mm of protective field height whose response time is
6 ms. The safety light curtain directly switches the contactors whose response time is con-
tained in the 250 ms. An additional interface therefore does not have to be taken into consider-
ation.
Ä Calculate safety distance S
K [mm/s] = 1600
T [s]
C [mm]
RT
S [mm]
RT
S [mm]
RT
This safety distance is not available in the application. This is why a new calculation is done
with a safety light curtain with 40 mm of resolution (response time = 14 ms):
Ä Re-calculate safety distance S
K [mm/s] = 1600
T [s]
C [mm]
RT
S [mm]
RT
S [mm]
RT
The safety light curtain with a 40 mm resolution is thus suitable for this application.
NOTICE For the calculation with K = 2000 mm/s, safety distance S
approach speed K = 1600 mm/s is therefore permitted.
Wieland Electric GmbH | BA001133 | 04/2017 (Rev. A)
RT
= Safety distance
the protective field: 2000 mm/s or 1600 mm/s, when S
= Total time of the delay, sum from (t
= Response time of the protective device
= Response time of the safety relay
= Stopping time of the machine
= Additional distance for access guarding with approach reaction with resolu-
tions of 14 to 40 mm, d = resolution of protective device C
14) mm. Additional distance for access guarding for resolutions > 40 mm:
C = 850 mm (standard value for arm length)
RT
using the formula acc. to EN ISO 13855.
RT
= (0.006 + 0.250)
= 850
= 1600 mm/s × 0.256 s + 850 mm
= 1260
using the formula acc. to EN ISO 13855.
RT
= (0.014 + 0.250)
= 8 ×~ (40 - 14)
= 1600 mm/s × 0.264 s + 208 mm
= 631
for access guarding
+ t + t )
a i m
equals 736 mm. The adoption of
RT
Mounting
> 500 mm
RT
= 8 × (d -
RT
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