Calculation Of Safety Distance If Protective Fields Act Orthogonally To The Approach Direction - Leuze electronic MLC 500 Original Operating Instructions

NOTICE
If longer stopping times are determined during regular inspections, an appropriate additional
time must be added to t
6.1.2

Calculation of safety distance if protective fields act orthogonally to the approach direction

With vertical protective fields, ISO 13855 differentiates between
• S : safety distance concerning access through the protective field
RT
• S : safety distance concerning access over the protective field
RO
The two values are distinguished by the way additional distance C is determined:
• C : from a calculation formula or as a constant (see chapter 6.1.1 "Calculation of safety distance S")
RT
• C : from the following table "Reaching over the vertical protective field of electro-sensitive protective
RO
equipment (excerpt from ISO 13855)"
The larger of the two values S
Calculation of safety distance S
field:
Calculation of safety distance S
S [mm]
RT
K [mm/s]
T [s]
t [s]
a
t [s]
i
t [s]
m
C [mm]
RT
Calculation example
The feeding-in area in a press with a stopping time (including press Safety PLC) of 190 ms is to be safe-
guarded with a safety light curtain with 20 mm of resolution and 1200 mm of protective field height. The
safety light curtain has a response time of 22 ms.
Ä Calculate safety distance S
K [mm/s]
T [s]
C [mm]
RT
S [mm]
RT
S [mm]
RT
S is smaller than 500 mm; this is why the calculation may not be repeated with 1600 mm/s.
RT
NOTICE
Implement the stepping behind protection required here, e.g., through the use of an additional or
cascaded safety sensor for area protection.
Leuze electronic
.
m
and S
RT RO
acc. to ISO 13855 when access occurs through the protective
RT
for point of operation guarding
RT
= Safety distance
= Approach speed for point of operation guarding with approach reaction and normal approach di-
rection to the protective field (resolution 14 to 40 mm): 2000 mm/s or 1600 mm/s, when
S > 500 mm
RT
= 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 point of operation guarding with approach reaction with resolutions of
14 to 40 mm, d = resolution of protective device C
using the formula acc. to ISO 13855.
RT
= 2000
= (0.022 + 0.190)
= 8 × (20 - 14)
= 2000 mm/s × 0.212 s + 48 mm
= 472
is to be used.
+ t + t )
a i m
MLC 520 Host/Guest
= 8 × (d - 14) mm
RT
Mounting
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