Configuration and Connection Examples 12.2010
6SE7087-6QX70 (Version AM) Siemens AG
2-54 Compendium Motion Control SIMOVERT MASTERDRIVES
♦ Determination of diagnostic coverage
Parameter Value Comment
DC(channel1) 99 %
Testing of -K1 via –K3 in feedback circuit of
–A1
DC(channel2) 99 %
Testing of -K2 in feedback circuit of –A1 on
Emergency Stop request
DC
avg
99 % → High
)2channel( DC )1channel( DCDC
avg
==
♦ Determination of Performance Level
• Structure of SRP/CS according to Category 3
• MTTF
d
is high
• DC
avg
is high
• Sufficient measures against common cause failure
According to EN ISO 13849-1:2008 Appendix K, PL e is achieved
with PFHd = 4.29 x 10
-8
/ h.
In accordance with ISO 13849-1, a minimum of 65 points are required
for SRP/CS from category 2.
The observations stated in subsection 2.4.5.2 "Measures against
comm
on cause failure (CCF) of the safety function" apply.
A sufficient total of 65 points is thus achieved.
Parameter PFH value PL Comment
ACQUIRE 4.29 x 10
-8
/ h e Emergency Stop button –S3
EVALUATE 3 x 5.4 x 10
-11
/ h e Safety switching devices –A1, –A2 and –A3
REACT 4.29 x 10
-8
/ h e Switching elements –K1 and –K2
Total 8.6 x 10
-8
/ h e < 1x10
-6
/ h
The requirements regarding PL d with Category 3 for the
protective door safety function are thus fulfilled.
Measures against
common cause
failure (CCF) of the
safety function
Check of the PFH
value of the safety
functions as a whole
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