User manual

26
7. Safety functions
System requirements
Database for failure rates
System type
Applied standard
Beta factor
SN 29500
Type B, consisting of sub-systems
IEC 61508
1 %
7.1. Safe switch-off ELR W3-24DC/500AC-... ELR W3-230AC/500AC-...
Ambient temperature 40°C 60°C 40°C 60°C
MTBF [years] Mean time to failure 45.6 23,0 46.0 23.0
Switch-off time [ms] 40 80
λsd [FIT] safe, detectable 666 1561 641 1217
λsu [FIT] safe, undetectable 947 1643 879 1814
λdd [FIT] dangerous, detectable 215 446 399 896
λdu [FIT] dangerous, undetectable 2.5 5.01 4.43 9.67
SFF [%] Safe Failure Fraction 99.86 99.9 99.77 99.75
DCS [%] Diagnostic coverage safe 50.56 48.73 42.17 40.2
DC [%] Diagnostic coverage 98.86 99 98.9 98.93
PFD Probability of Failure on Demand compare diagram 7.3. compare diagram 7.3.
PFH Probability of a dangerous failure
per hour
2.48 x 10
-9
5.01 x 10
-9
4.43 x 10
-9
9.67 x 10
-9
Safety level according to IEC 61508-1: SIL 3
ISO 13849-1: PL e
EN 954-1: Category 3
7.2. Motor Protection ELR W3-24DC/500AC-... ELR W3-230AC/500AC-...
Ambient temperature 40°C 60°C 40°C 60°C
Switch-off time [ms] according to Class 10 A, IEC 60947
λsd [FIT] safe, detectable 645 1487 647 1212
λsu [FIT] safe, undetectable 866 1408 812 1622
λdd [FIT] dangerous, detectable 238 488 413 915
λdu [FIT] dangerous, undetectable 17 37 17 37
SFF [%] Safe Failure Fraction 99 98.9 99.1 99
DCS [%] Diagnostic coverage safe 42.6 51.36 44.4 42.8
DC [%] Diagnostic coverage 93.3 93 96 96.1
PFD Probability of Failure on Demand compare diagram 7.4. compare diagram 7.4.
Safety level according to IEC 61508-1: SIL 2