Siemens SIMATIC KP8, Operating Instructions Manual

Page: 88 / 106

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