Safety Data - ABB ACS880-107 Hardware Manual

168 The Safe torque off function

Safety data

The safety data for the Safe torque off function is given below.
Note: The safety data is calculated for redundant use, and does not apply if both STO
channels are not used.
Frame SIL/
SC
size SILCL
R1i
R2i
3 3
R3i
R4i
R5i 3 3
R6i
3 3
R7i
R8i 3 3
2×R8i 3 3
3×R8i 3 3
4×R8i 3 3
5×R8i 3 3
6×R8i 3 3
7×R8i 3 3
8×R8i 3 3
9×R8i 3 3
10×R8i 3 3
•
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 (frames R1i...R7i) or type B (frame R8i) 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.
•
STO reaction time (shortest detectable break): 1 ms
•
STO response time:
•
Frame sizes R1i...R7i: 2 ms (typical), 5 ms (maximum)
•
Frame sizes 1×R8i...10×R8i: 2 ms (typical), 25 ms (maximum)
•
Fault detection time: Channels in different states for longer than 200 ms
•
Fault reaction time: Fault detection time + 10 ms
•
STO fault indication (parameter 31.22) delay: < 500 ms
•
STO warning indication (parameter 31.22) delay: < 1000 ms
PFH
SFF (T = 20
PFD
1
PL
a)
(T
(%) (1/h)
e 98.8 3.23E-09 2.83E-05 7.08E-05 24293
e 96.9 3.36E-09 2.03E-05 5.07E-05 17021
e 98.7 3.55E-09 3.38E-05 8.45E-05
e >99 4.74E-11 4.23E-07 1.04E-06 27325
e >99 5.57E-11 4.98E-07 1.22E-06 19607
e >99 6.39E-11 5.74E-07 1.41E-06 15295
e >99 7.22E-11 6.49E-07 1.59E-06 12540
e >99 8.05E-11 7.24E-07 1.78E-06 10626
e >99 8.87E-11 7.99E-07 1.96E-06
e >99 9.70E-11 8.75E-07 2.14E-06
e >99 1.05E-10 9.50E-07 2.33E-06
e >99 1.14E-10 1.03E-06 2.51E-06
e >99 1.22E-10 1.10E-06 2.69E-06
MTTF
PFD
D
avg avg
= 2 a) (T = 5 a)
1 1
(a)
9041
9220
8142
7290
6600
6029
DC
Cat. HFT CCF
(%)
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
> 90
3 1 80
Lifetime
(a)
20
20
20
20
20
20
20
20
20
20
20
20
20