38 Technical data
Multiples of frame size R8i
Above values for frame sizes R7/R7i/R8/R8i apply for the multiples of frame size R8i,
except for values of PFH, PFD
PFH
Frame size
(1/h)
T
= 20 a
1
2×R8i
1.74E-09
3×R8i
2.62E-09
4×R8i
3.49E-09
5×R8i
4.36E-09
6×R8i
5.23E-09
7×R8i
6.10E-09
8×R8i
6.97E-09
9×R8i
7.85E-09
10×R8i
8.72E-09
11×R8i
9.59E-09
12×R8i
1.05E-08
•
The following temperature profile is used in safety value calculations:
•
670 on/off cycles per year with T = 71.66 °C
•
1340 on/off cycles per year with T = 61.66 °C
•
30 on/off cycles per year with T = 10.0 °C
•
32 °C board temperature at 2.0% of time
•
60 °C board temperature at 1.5% of time
•
85 °C board temperature at 2.3% of time.
•
The STO is a type A safety component as defined in IEC 61508-2.
•
Relevant failure modes:
•
The STO trips spuriously (safe failure)
•
The STO does not activate when requested
A fault exclusion on the failure mode "short circuit on printed circuit board" has been
made (EN 13849-2, table D.5). The analysis is based on an assumption that one
failure occurs at one time. No accumulated failures have been analyzed.
•
Reaction times are described in section
response times
and MTTF
avg
PFD
PFD
avg
avg
T
= 2 a
T
= 5 a
1
1
1.61E-05
3.90E-05
2.41E-05
5.84E-05
3.21E-05
7.79E-05
4.01E-05
9.74E-05
4.82E-05
1.17E-04
5.62E-05
1.36E-04
6.42E-05
1.56E-04
7.23E-05
1.75E-04
8.03E-05
1.95E-04
8.83E-05
2.14E-04
9.63E-05
2.34E-04
3AXD10000342876 Rev B
on page 14.
. These values are listed below.
D
MTTF
D
(a)
2497
1664
1248
999
832
713
624
555
499
454
416
STO function activation and indication