Siemens SIMATIC KP8 - Page 110

Technical specifications
9.4 Fail-safe mode
KP8, KP8F, KP32F
110 Operating Instructions, 11/2011, A5E03284305-02
Input unit – 1oo2 mode
Parameter Value Comment
Hardware Fault Tolerance 1 –
Classification A –
Architecture 1oo2D 1st detected failure leads to the safe
state
Failure mode
• Detected
• Undetected
Dangerous process value
• 5.78 FIT
• 0.06 FIT
Due to failures in the input circuit
One channel
One channel
Failure Mode Diagnostic
• Detected
• Undetected
No error signaling or no safe
values
• 0 FIT
• 0 FIT
Calculation according
IEC 13849-1, CAT4
Diagnostic Coverage 99.00 % –
Diagnostic test interval 15 ms Errors detected in each firmware cycle
Safe Failure Fraction 99.86 % –
Common Cause Factor 2 % –
Controller
Parameter Value Comment
Hardware Fault Tolerance 1 –
Classification B –
Architecture 1oo2D 1st detected failure leads to the safe
state
Failure mode
• detected
• undetected
Dangerous process value
• 174,00 FIT
• 1,68 FIT
Due to failures in the processing unit
• One channel
• One channel
Failure Mode Diagnostic
• Detected
• Undetected
No error signaling or no safe
values
• 0 FIT
• 0 FIT
Calculation according
IEC 13849-1, CAT4
Diagnostic Coverage 99.04 % –
Diagnostic test interval 15 ms Errors detected in each firmware cycle
Safe Failure Fraction 99.23 % –
Common Cause Factor 2 % –