Leuze electronic MLC 500 - Calculation of Safety Distance S for Parallel Approach to the Protective Field

Mounting
Leuze electronic MLC 510 24
6.1.3 Calculation of safety distanceS for parallel approach to the protective field
Calculation of safety distanceS for danger zone guarding
S [mm] = Safety distance
K [mm/s] = Approach speed for danger zone guarding with approach direction parallel to the protective field
(resolution up to 90mm): 1600mm/s
T [s] = Total time of the delay, sum from (t
a
+t
i
+t
m
)
t
a
[s] = Response time of the protective device
t
i
[s] = Response time of the safety relay
t
m
[s] = Stopping time of the machine
C [mm] = Additional distance for danger zone guarding with approach reaction H=height of the protec-
tive field, H
min
=minimum installation height permitted, but no smaller than0, d=resolution of
the protective device C=1200mm-0.4×H; H
min
=15×(d-50)
Calculation example
The danger zone in front of a machine with a stopping time of 140ms is to be safeguarded as close to the
floor height as possible using a horizontal safety light curtain as a replacement for a PS mat. Installation
heightH
min
can be=0 - additional distanceC to the safety distance is then 1200mm. The shortest possible
safety sensor is to be used; the first value to be selected is to be 1350mm.
The receiver with 40mm of resolution and 1350mm protective field height has a response time of 13ms,
an additional relay interface a response time of 10ms.
Ä Calculate safety distanceS
RO
using the formula acc. to ISO13855.
K [mm/s] = 1600
T [s] = (0.140+0.013+0.010)
C [mm] = 1200
S [mm] = 1600mm/s×0.163s+1200mm
S [mm] = 1461
The safety distance of 1350mm is not sufficient; 1460mm are necessary.
This is why the calculation is repeated with a protective field height of 1500mm. The response time is now
14ms.
Ä Re-calculate safety distanceS
RO
using the formula acc. to ISO13855.
K [mm/s] = 1600
T [s] = (0.140+0.014+0.010)
C [mm] = 1200
S [mm] = 1600mm/s×0.164s+1200mm
S [mm] = 1463
A suitable safety sensor has been found; its protective field height is 1500mm.