IEC 61511:2016 Ed2 in relation to C
PT
CL 11.9.2 d) “
the estimated failure related
to each mode, due to random hardware
failure, which would contribute to a
dangerous failure of the SIS which are
undetected by the diagnostic tests and
undetected by proof test
”
CL 11.9.5 b) “
evaluate the effect of
possible improvement measures on the
identified devices or parameters (e.g., more
reliable devices, additional defences
against common mode failures, increased
diagnostic or proof test coverage,
increased redundancy, reduced proof test
interval, staggering tests, etc.);
”