Fail-Safe Mode - Siemens SIMATIC HMI KP Series Operating Instructions Manual

Technical specifications

9.3 Fail-safe mode

9.3 Fail-safe mode
KP8F internal
The block diagram of the KP8F:
The relevant values of the individual blocks are shown in the following.
Note
All values for the following data are based on the SN 29500:2005 and an ambient
temperature of 60 °C.
Input unit – 1oo1 mode
Parameter
Hardware Fault Tolerance
Classification
Architecture
Failure mode
Detected

Undetected

Failure Mode Diagnostic
Detected

Undetected

Diagnostic Coverage
Diagnostic test interval
Safe Failure Fraction
86
Value
0
A
1oo1D
Dangerous process value
5.50 FIT

0.34 FIT

No error signaling or no safe
values
0 FIT

0 FIT

94.15 %
15 ms
99.19 %
Comment
–
–
–
Due to failures in the input circuit
Calculation according
IEC13849:2006 CAT4
–
Errors detected in each firmware
cycle
–
Operating Instructions, 10/2010, A5E03284305-01
KP8, KP8F