Description
Term
Performance level. Levels a...e correspond to SIL (EN ISO 13849-1)
PL
Prevention of unexpected start-up
POUS
Systematic capability (IEC 61508)
SC
Safety integrity level (1...3) (IEC 61508)
SIL
Maximum SIL (level 1...3) that can be claimed for a safety function or subsystem
(IEC/EN 62061)
SILCL
Safe torque off (IEC/EN 61800-5-2)
STO
Proof test interval. Defines the probabilistic failure rate (PFH or PFD
avg
) for the safety
function or subsystem. Performing a proof test at a maximum interval of T
1
is required
to keep the SIL capability valid. The same interval must be followed to keep the PL
capability (EN ISO 13849) valid. Note that any T
1
values given cannot be regarded
as a guarantee or warranty.
T
1
14 Introduction to the manual