User Documentation
9
Notesonconguring
1438130000/02/07-2018
3.1 Lowdemandmodeof
operation according to
EN 61508
The SIL3 relays from the SAFESERIES are used in
low demand mode, when their demand frequency
is no more than one times per year and no more
than double the repeated testing frequency (refer to
DIN EN 61508-4, 3.5.12).
For the demand rate and the associated PFD pa-
rameters at an inspection interval Tproof of 12 years,
the values indicated in Table 2 apply.
3.2 Highdemandmodeof
operation according to
EN 61508
If the “low demand mode of operation” usage can-
not be applied, then the SIL3 relay should be used
as a safety-critical sub-system operating at high de-
mand mode or continuous mode (DIN EN 61508-4,
3.5.12). For the demand rate and the associated
PFH parameters, the values indicated in the follow-
ing table 3 apply:
3.3 Highdemandmodeof
operation according to
EN ISO 13849-1
For the demand rate and the associated PFH pa-
rameters, the values indicated in Table 4 apply.
3.4 Typesofmalfunctions
A safe failure is not able to render a technical safety
system dangerous or non-functional. The SIL3 relay
passes to a predened safe state.
A dangerous, undetected failure has the potential to
render a technical safety system dangerous or non-
functional. The SIL3 relay does not pass to a prede-
ned safe state.
3.5 Test intervals
The test interval or inspection interval T
proof
is the timeframe in which tests are conduct-
ed in full and are repeated.
All hardware failures are recognised within
this period of time.
3 Notes on conguring