12.2010 Configuration
and Connection Examples
Siemens AG
6SE7087-6QX70 (Version AM)
SIMOVERT MASTERDRIVES
Compendium Motion Control
2-53
♦
Determination of MTTF
d
value
Parameter
Value
Comment
Channel 1
Safety relay –K1
B10
d
value
20.000.000
Specified by manufacturer
nop 24972
per
year
24960 per year due to protective door
+ 12 per year due to Emergency Stop
MTTF
d
(-K1)
8008 years
op
d
d
n
1
,
0
10
B
MTTF
×
=
Interim result channel 1
MTTF
d
(channel1)
8008 years
Capped to 100 years
Channel 2
Line contactor –K2
B10
d
value
1.333.333
Specified by manufacturer
nop
12 per year
12 actuations per year due to Emergency Stop
MTTF
d
(-K2) 1,111,111
years
op
d
d
n
1
,
0
10
B
MTTF
×
=
Interim result
Channel 2
MTTF
d
(channel2)
1,111,111 years
Capped to 100 years
Interim results for REACT (channels 1 and 2)
MTTF
d
(REACT)
100 years
→
High
MTTF
d
values of both channels have been
capped to 100 years
→
It is not necessary to symmetrize both
channels.