Functional safety
Instruction handbook
Safe STO logic
BM5-SSL
Document No. 5.18007.02
Baumüller Nürnberg GmbH
26
4.4
The values are valid at the desired environmental conditions, see
PFH
Probability of dangerous Failure per Hour
HFT
Hardware Fault Tolerance
Safety Integrity Level‘
SIL2, high demand mode
PFH
< 1 x 10
-8
HFT
1
MTTF
D
Mean Time To Failure
DC
avg
Diagnostic Coverage
Performance level
PLd, category 3
MTTF
D
high
DC
avg
medium
WARNING!
Demands on the function test of the safety function to comply with the safety integrity
level
SIL2
respectively the performance level
PLD, category 3
:
At least once a year the safety function has to be activated and deactivated again.
At least once a year the voltage at the STO outputs in state STO must be measured,
it must be lower than 5 V.
No proof test is necessary during the expected life service of 20 years.
Characteristics according IEC 61508
Characteristics according DIN EN ISO 13849-1
Summary of Contents for BM5-SSL
Page 79: ......