User Documentation

Safety parameters
1482900000/01/11.2017 13
8. Safety parameters
Safety parameter
Ex input SIL2
Proof-test interval (T
proof
), (10 % of loop PFD)
3 years
Safe Failure Fraction (SFF)
90.7 %
Demand response time, opto output
Signal input: < 0.5 s
Temperature input: < 1.1 s
Demand mode
High
Demand rate
3000 s
Diagnostic test interval
30 s
Mean Time To Repair (MTTR)
24 h
Hardware Fault Tolerance (HFT)
0
Component type
B
SIL capability
SIL 2
Description of the “safe state”
Output ≤ 3.6 mA or output ≥ 21 mA
PFD
AVG
PFH (see note 1)
T
proof
= 1 year
T
proof
= 2 years
T
proof
= 5 years
3.96 × 10
-4
6.5 × 10
-4
1.41 × 10
-4
6.1 × 10
-8
h
-1
PFD
AVG
= Average Probability of Failure on Demand
PFH = Probability of dangerous Failure per Hour
Note 1: The ACT20X-(2)HTI-(2)SAO contains no lifetime limiting components, therefore the PFH figures
are valid for up to 12 years, according to IEC 61508.