404 Appendix: Safe torque off (STO)
Data related to safety standards
Abbreviations
Maintenance
Test the operation and reaction of the STO function every year.
IEC 61508 EN/ISO 13849-1 IEC 62061
SIL 3 PL e SILCL 3
PFH 6.48E-09
(6.48 FIT)
Category 3
HFT 1 MTTFd 470 years
SFF 91% DCavg 18%
Abbreviation Reference Description
CCF EN/ISO 13849-1 Common Cause Failure (%)
DCavg EN/ISO 13849-1 Diagnostic Coverage Average
FIT Failure In Time: 1E-9 hours
HFT IEC 61508 Hardware Fault Tolerance
MTTFd EN/ISO 13849-1 Mean Time To dangerous Failure: (The total number of
life units) / (the number of dangerous, undetected
failures) during a particular measurement interval under
stated conditions
PFHd IEC 61508 Probability of Dangerous Failures per Hour
PL EN/ISO 13849-1 Performance Level: Corresponds SIL, Levels a-e
SFF IEC 61508 Safe Failure Fraction (%)
SIL IEC 61508 Safety Integrity Level
STO EN 61800-5-2 Safe Torque Off
To Next Page
Loading...
