The Drive Safety Function Failure Rate - Delta C2000 Plus Series User Manual

Chapter 17 Safe Torque Off Function | C2000 Plus
17-1

The Drive Safety Function Failure Rate

Item
SFF Safe Failure Fraction
HFT (Type A
Hardware Fault Tolerance
subsystem)
SIL Safety Integrity Level
Average frequency of dangerous failure
PFH
[h-1]
Probability of Dangerous Failure on
PFD
av
Demand
Category Category
PL Performance level
MTTF Mean time to dangerous failure
d
DC Diagnostic coverage
Definition
17-2
Standard Performance
Channel 1: 80.08%
IEC61508
Channel 2: 68.91%
IEC61508 1
IEC61508 SIL 2
IEC62061 SILCL 2
IEC61508 9.56×10
IEC61508 4.18×10
ISO13849-1 Category 3
ISO13849-1 d
ISO13849-1 High
ISO13849-1 Low
-10
-6