SE4-PLUS Series
Instruction Manual
11
2.2.1. Minimum installation distance
The safety device must be placed at a specific safety distance
(Fig.5).
This distance must ensure that the dangerous zone cannot be
reached before the dangerous motion of the machine has been
stopped by the ESPE.
The safety distance depends on 4 factors, according to the EN-
999, 775 and 294 Standards:
1
Response time of the ESPE (the time between the effective
beam interruption and the opening of the OSSD contacts).
2
Machine stopping time (the time between the effective opening
of the contacts of the ESPE and the real stop of the dangerous
movement of the machine).
3
ESPE resolution
4
Approaching speed of the object to be detected.
Fig. 5
The following formula is used for the calculation of the safety
distance:
S = K (t
1
+ t
2
) + C
where
:
S
= Minimum safety distance in mm.
K
= Speed of the object, limb or body approaching the
dangerous area in mm/sec.
t
1
= Response time of the ESPE
in seconds
(
see section 9 “Technical data”
)
t
2
= Machine stopping time in seconds.
d
= Resolution of the system.
C
=
8 (d -14)
for device with resolution
40mm
