Power Supply - Siemens SIMATIC KP8 Operating Instructions Manual

Technical specifications
9.3 Fail-safe mode

Power supply

Parameter
Hardware Fault Tolerance
Classification
Architecture
Failure mode


Failure Mode Diagnostic


Diagnostic Coverage
Diagnostic test interval
Safe Failure Fraction
Fail-safe mode for 1oo1 evaluation
● In accordance with IEC 61508:2010
● In accordance with IEC 13849:2006
● In accordance with EN 954-1:1996
88
Detected
Undetected
Detected
Undetected
Systematic Capability
Mode of operation
Meantime to Restoration (MTTR)
Probability of a dangerous failure per hour
(PFH)
Probability of a dangerous failure on demand
(PFD)
Safe Failure Fraction (SFF)
Diagnostic test interval
Proof Test Interval
Lifetime
Meantime to Failure (MTTF
Meantime to Restoration (MTTR)
Diagnostic Coverage (DC
Performance Level
Category
Category
Value
0
A
1oo1D
Dangerous process value
22.50 FIT

0.22 FIT

No error signaling or no safe
values
0 FIT

0 FIT

99.03 %
< 10 ms
99.84 %
SIL3
High and low demand mode
100 h
5.95 × 10
2.61 × 10
99.19 %
15 ms
10 y
10 y
) 560 y
d
100 h
) 98.90 %
avg
d
3
3
Comment
–
–
–
Due to failures in the power supply
Calculation according
IEC13849:2006 CAT4
–
Voltage monitoring in hardware
–
1/h
–10
–5
Operating Instructions, 10/2010, A5E03284305-01
KP8, KP8F