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3.3 Calculation of Minimum Distance for Installation
The distance S is the minimum distance between light curtain/grid and hazardous area which prevents that
anyone comes in contact with hazardous machinery in operation before it stops. For calculation of S for a
curtain with multiple beams, the following is valid according to EN ISO 13855:2010:
Vertically assembled light curtain/grid
The minimum distance S for a vertically assembled light curtain/grid is determined in three steps:
a) Calculate minimum distance for reaching through the detection zone, S
b) Calculate minimum distance for reaching over the detection zone, S
c) Compare S
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NB! If access to the hazardous area by reaching over the light curtain/grid can be excluded, e.g. by the
provision of guards or other protective measures, step b) and c) are not necessary.
a)
S
= (K × T) + C
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= approach speed of body parts towards hazardous area:
K
= 2000 mm/s shall be used if S is equal to or less than 500 mm. Min. value of S = 100 mm.
NB! If FII-4-30 is used in single/double break mode min. value of S > 150 mm.
= 1600 mm/s can be used if S is greater than 500 mm. Min. value of S = 500 mm.
= Overall system stopping performance
T
T1 = reaction time of light curtain/grid (s)
T2 = stopping time of machine, including reaction time of control system (s)
C
= 8 × (d-14) mm for FII-4-14 and FII-4-30 (light curtains)
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NB! If floating blanking is used and resolution ≥ 40 mm then C
= 850 mm for FII-4-K versions (light grids)
d
= resolution (mm) = 14 mm for FII-4-14 and 30 mm for FII-4-30.
NB! If floating blanking is used, see resolution table in chapter 9.
____________________________
1
) The maximum time required from actuation of the AOPD until the hazardous machine function is
terminated.
www.abb.com/lowvoltage
and S
. The minimum distance S is the greater of the two.
RO
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1
= T1 + T2, where:
11
.
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.
RO
S
= safety distance in mm.
H1 = the bottom beam shall not
have a height above 300 mm.
H2 = the top beam shall not have a
height below 900 mm.
= 850 mm.
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2TLC172015M0201, rev. D
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