User Documentation
Table Of Contents
- 1.1 Revision history
- 1.2 Validity
- 1.3 Contact address
- Table of contents
- 2. Observed standards
- 3. Acronyms and abbreviations
- 4. Purpose of the product
- 5. Assumptions and restrictions for use of the product
- 6. Functional specification of the safety functions
- 7. Functional specification of the non-safety functions
- 8. Safety parameters
- 9. Failure category SIL 2
- 10. Hardware and software configuration
- 11. Periodic proof test procedure
- 12. Procedures to repair or replace the product
- 13. Maintenance
- 14. Connection diagram
Safety parameters
1482850000/01/11.2017 11
8. Safety parameters
Safety parameter
Ex output SIL2
Proof-test interval (T
proof
), (10 % of loop PFD)
5 years
Safe Failure Fraction (SFF)
85 %
Demand mode
High
Demand rate
(see note 1)
Mean Time To Repair (MTTR)
24 h
Hardware Fault Tolerance (HFT)
0
Component type
A (see note 2)
SIL capability
SIL 2
Description of the “safe state”
Output ≤ 3.6 mA or output ≥ 21 mA
Note 1: Depends on detection time in external controller. If detection time is xx seconds, the demand
rate shall be 100 times xx seconds.
Note 2: Simple device (type A) where microprocessors and software have no effect on safety output.
PFD
AVG
PFH (see note 1)
T
proof
= 1 year
T
proof
= 2 years
T
proof
= 5 years
2.29 × 10
-4
4.37 × 10
-4
1.06 × 10
-4
4.8 × 10
-8
h
-1
PFD
AVG
= Average Probability of Failure on Demand
PFH = Probability of dangerous Failure per Hour
Note 1: The ACT20X-(2)SAI-(2)HAO contains no lifetime limiting components, therefore the PFH figures
are valid for up to 12 years, according to IEC 61508.