51
UK
13 Terms and abbreviations
ESPE
Electro-Sensitive Protective Equipment�
Cat�
Category
Category
Classification of the safety-related
parts of a controller as regards their
resistance to failures�
CCF
Common Cause Failure
Common cause failure
DC
Diagnostic Coverage
Diagnostic coverage�
MTTF
Mean Time to Failure
Mean time to failure�
MTTF
d
Mean Time To Dangerous
Failure
Mean time to dangerous failure�
OSSD
Output Signal Switching Device Output signal switch element,
static safety-related output�
PFH
(PFH
D
)
Probability of (dangerous)
Failure per Hour
Probability of a (dangerous) failure per
hour�
PL
Performance Level
PL to EN ISO 13849-1
SIL
Safety Integrity Level
SIL 1-4 to IEC 61508
PLC
Programmable Logic Controller
Technical data and further information at
www�ifm�com