9
SLC 420
SLG 420
Operating instructions
Safety light curtain/safety light grid
EN
Safety distance to the hazardous area
S
Hazardous
point
Transmitter
Receiver
Command device
Authorised operation
Mechanical protection
Direction from which
the hazardous area
is accessed
The safety distance between the safety light curtain and the
hazardous point must always be respected and observed If
a person reaches the hazardous point before the hazardous
movement has come to a standstill, he or she is exposed to
serious injuries
Safety distance to the hazardous area
Limit of the hazardous point
Safety distance (S)
Protection field
marking
Tool - upper part
Signal to stop the
hazardous movement
Standstill of the
hazardous movement
t
n
= t
B
- t
A
Tool - lower part
t
A
S
t
B
≤ 75 mm = max. distance for protection against stepping over
To prevent persons from stepping over the protection field this dimension must be
imperatively respected and observed
The formulae and calculation examples are related to the vertical set-up
(refer to drawing) of the light curtain with regard to the hazardous point
Please observe the applicable harmonised EN standards and possible
applicable national regulations
To calculate the minimum distances of the safety guards with
regards to the hazardous point, the EN ISO 13855 must be
observed
If reaching through the protection field is possible, take care
with the calculation of the safety distance and add an amount
as per norm EN ISO 13855
The norm EN ISO 13855 defines two types of safety distances,
- Access
through
the protection area with an additional distance C,
according to the resolving power
- Access
over
the protection area with an additional distance C
RO
according to table 1
If it is possible to reach through the hazardous area (vertical alignment)
then both values C and C
RO
have to be determined The larger of the
two values is to be used for calculating the safety distance Calculating
the safety distance with C
RO
:
S
CRO
= K x T + C
RO
K
= Approach speed
T = Total reaction time (machine run-on time, reaction time of the safety
guard, relays, etc)
C
RO
= Additional distance due to reaching through the hazardous area
with parts of body, see table 1 for value
1
2
3
KxT
S
RO
C
RO
a
b
1 Safety sensor
2 Hazardous point
3 Floor
a Height of the hazardous point
b Height of the topmost beam of the safety sensor