8
OMRON Scientific Technologies Inc.
© OMRON STI 0613 PN99804-0060 Rev. B
24
NOTE!
T
s
+ T
c
is usually measured together by a stop time measuring device.
T
r
=
the response time of the MS4800 system, in seconds. This response time is given in
Table 13-1
.
WARNING!
When using an Omron STI RM-X, RM-1 or RM-2AC with the MS4800 system, add 8ms
to the response times stated in
Table 13-1
.
T
bm
=
the additional stopping time, in seconds, allowed by the brake performance monitor before it
detects stop time deterioration.
The T
bm
factor allows consideration for brake wear, adding extra stop time allowed by the brake
monitor. Therefore, T
bm
= Brake monitor set point - (T
s
+ T
c
).
NOTE!
If the guarded machine is not equipped with a stop time performance monitor, a percentage
increase factor should be applied to the stop time of the machine to allow for braking system wear.
Contact your machine manufacturer for information.
D
p
f
=
This is related to the minimum object sensitivity of the MS4800 system. By knowing the
minimum object sensitivity, S, of the MS4800 system, D
pf
is read directly from
Table 4-5
,
Table 4-6
,
Table 4-7
or
Table 4-8
depending on the minimum object sensitivity of the system being installed.
8 . 2 E
UR OP EA N
S
AF ET Y
D
I S T A NC E
F
O RM UL AS
The following discussion is based on standard EN999 and applies to light curtains used in industrial
environments.
8.2.1
S
AFETY
D
ISTANCE
F
ORMULA
FOR
S
YSTE MS
WITH
A
M
INIMUM
O
BJE CT
R
ES OLUTION
OF
40
MM
OR
L
ESS
When the minimum object resolution of the system is 40 mm or less, use the following formula:
S = (K x T) + C
where:
S = the minimum distance in millimeters, from the danger zone to the detection point, line, plane or
zone.
K = 2000 mm/s
T = the overall system stopping performance in seconds.
T = t
1
+ t
2
t
1
= response time of the safety light curtain in seconds. This response time is given in
Table 13-
1
.
t
2
= maximum stopping time of the machine in seconds.
C = 8(d-14 mm), but not less than zero.
d = the minimum object resolution of the MS4800 system in millimeters. therefore,
S = (2000 mm/s x T) + 8(d – 14 mm)
This formula applies for all minimum distances of S up to and including 500 mm. The minimum value
of S shall not be less than 100 mm.
If S is found to be greater than 500 mm using the formula above, then the formula below can be used.
In this case the minimum value of S shall not be less than 500 mm.
S = (1600 mm/s x T) + 8(d – 14 mm)
8.2.2
S
AFE TY
D
ISTA NCE
F
ORMULA
FOR
S
YSTEMS
WITH
A
M
INIMUM
O
BJECT
R
ESOL UTIO N
G
REATER
T
HAN
40
MM
When the minimum object resolution of the system is greater than 40 mm, use the following formula:
S = (K x T) + C
▲
!
▲
!
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