Horizontal safeguarding of hazard zones with a light grid (EN 999 / ISO 13855)
13
Sample calculation of safety clearance
during horizontal safeguarding of hazard
zones using
ULCT
light curtains:
Example:
Safety light curtain
ULCT1200/144
Light curtain's reaction time:
t1: 17 ms
Machine's run-on time
t2: 50 ms
H = 200 mm
The safety clearance is:
S = (1600 mm /s x (0,050 s + 0,017 s)) +
(1200 mm - 0,4 x 200 mm)
S =1228 mm
With the ULCT 1200/144, the protective
field has a depth of 1200 mm.
The distance
a
between the last beam and
the hazard zone's front edge is therefore
28 mm + 5 mm = 33 mm (the last beam
must be added).
Formula for calculating safety clear-
ance during horizontal safeguarding of
hazard zones using light curtains:
In this case:
K = 1600 mm/s
C = 1200mm-0,4H, ut smaller than
850 mm, H being the height of the
protective field in mm above the
reference plane, e.g. the floor
T = t1 + t2
(also refer to Page 12)
t1 = Protective mechanism's
reaction time
t2 = Machine's run-on time
If the protective field is at a height of
≥
300 mm above the floor, there is a
danger of slipping beneath it. This must
be considered when assessing risks.
Accordingly, at
H
≥
300 mm:
1200 - 0,4 x H > 850 mm
The clearance a to the end of the
protective field (between the last
beam and the hazard zone's front
edge) must not exceed:
Example:
Height 200 mm
a
max
= 200 / 15 + 40 mm
a
max
= 53 mm
S = (1600 mm / s x T) + (1200 mm - 0,4 H)
a = H / 15 + 40 mm
S
= Safety clearance
From the start of the protective field
(1
st
beam) to the hazard zone's front
edge
H
Hazard zone's front edge
H = Protective field's height with respect to the reference plane
S = (K x T) + C
a
= Protective field's distance
From the last beam to the hazard
zone's front edge
S
a
Fig. 13/1: Horizontal safeguarding
Table of Contents
2
Assembly
2.2
Safety clearance
FIESSLER
E L E K T R O N I K
Fiessler Elektronik GmbH & Co. KG
Telefon: +49 (0) 711 / 91 96 97-0 Internet: http://www.fiessler.de
Telefax: +49 (0) 711 / 91 96 97-50 eMail: [email protected]
Doku Nr. 1121 Stand 08.01. 2018 RK/Aui
