Vega VEGABAR 54 Operating Instructions Manual page 61

Fault reaction time
General data
Proven in use
VEGABAR 54 - 4 ... 20 mA/HART
values relate to an average ambient temperature during
operation of +40°C (104°F). The calculations are further based
on the instructions stated in chapter "Planning".
Overfill protection/monitoring upper pressure value
Interference current
λ
sd
λ
su
λ
dd
λ
du
DC
S
DC
D
Dry run protection/monitoring lower pressure value
Interference current
λ
sd
λ
su
λ
dd
λ
du
DC
S
DC
D
Error E013 (no measured value)
Error E041 (hardware error)
Error E036 (software error)
MTBF = MTTF + MTTR
max. useful life of the measuring system for the safety
function
The judgment of the modification service was part to ensure
"Proven in use".
Functional safety acc. to IEC 61508-4 (SIL)
"fail high"
378 FIT
233 FIT
147 FIT
183 FIT
62 %
45 %
"fail high"
149 FIT
233 FIT
366 FIT
194 FIT
39 %
65 %
"fail low"
20 FIT
233 FIT
505 FIT
183 FIT
8 %
73 %
"fail low"
495 FIT
233 FIT
20 FIT
194 FIT
68 %
9 %
<2 sec
<20 sec
<1 h
6
0.9x10 h
approx. 10 years
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