Safety Data - ABB ACS880-37LC Hardware Manual

196 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.
SIL/
Frame size PL
SILCL
R8i 3 e
2×R8i 3 e
3×R8i 3 e
4×R8i 3 e
5×R8i 3 e
6×R8i 3 e
7×R8i 3 e
8×R8i 3 e
• The following temperature profile is used in safety value calculations:
• 670 on/off cycles per year with ΔT = 71.66 °C
• 1340 on/off cycles per year with ΔT = 61.66 °C
• 30 on/off cycles per year with ΔT = 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 B 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 response times:
• STO reaction time (shortest detectable break): 1 ms
• STO response time: 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
• Indication delays:
• STO fault indication (parameter 31.22) delay: < 500 ms
• STO warning indication (parameter 31.22) delay: < 1000 ms
PFH
SFF PFD
avg
(T = 20 a)
1
(%) (T = 2 a)
1
(1/h)
>99 5.0E-11 4.5E-07
>99 6.2E-11 5.5E-07
>99 7.3E-11 6.5E-07
>99 8.4E-11 7.6E-07
>99 9.5E-11 8.6E-07
>99 1.1E-10 9.6E-07
>99 1.2E-10 1.1E-06
>99 1.3E-10 1.2E-06
PFD MTTF DC
avg D
(T = 5 a) (a) (%)
1
1.1E-06 23970 ≥90
1.3E-06 16330 ≥90
1.6E-06 12390 ≥90
1.9E-06 9980 ≥90
2.1E-06 8360 ≥90
2.4E-06 7190 ≥90
2.6E-06 6310 ≥90
2.8E-06 5620 ≥90
T
M
Cat. SC HFT CCF
(a)
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3 3 1 80 20
3AXD10000078136 F