Failure Rate Of Ied-S' Safety Function - Delta IED-S Series User Manual

Chapter 15 IED-S Safe Torque Off Function | IED-S

15-1 Failure Rate of IED-S' Safety Function

Item
SFF
HFT (Type A
subsystem)
SIL
PFH
PFD
av
Category
PL
MTTF
d
DC
Definition
Safe Failure Fraction
Hardware Fault Tolerance
Safety Integrity Level
Average frequency of dangerous failure
[h-1]
Probability of Dangerous Failure on
Demand
Category
Performance level
Mean time to dangerous failure
Diagnostic coverage
Standard
IEC61508
IEC61508
IEC61508
IEC62061
IEC61508
IEC61508
ISO13849-1
ISO13849-1
ISO13849-1
ISO13849-1
15-2
Performance
Channel 1: 80.08%
Channel 2: 68.91%
1
SIL 2
SILCL 2
9.56×10 -10
-6
4.18×10
Category 3
d
High
Low