Allen-Bradley 1734-OB8S

204 Rockwell Automation Publication 1734-UM013N-EN-P - September 2017
Appendix D Safety Data
Mission Time for all modules is 20 years.
All 1734-IB8S safety input channels and all 1734-OB8S safety output channels
must utilize pulse testing when used in Functional Safety applications.
Cat. No.
Proof Test
Interval
(Mission
Time)
PFD
PFH
(1/hour)
Spurious Trip Rate (STR)
(1)
(1) Calculated based on ISA TR-84 method.
MTTF
spurious
(2)
(years)
(2) Mean time to failure (Spurious).
Year Hour
1734-IB8S
Series A
1 8760 2.11E-06
5.10E-10 2.666E-06 42.78
2 17520 4.23E-06
5 43800 1.06E-05
10 87600 2.11E-05
20 175200 4.23E-05
1734-OB8S
Series A
1 8760 2.13E-06
5.14E-10 3.229E-06 35.33
2 17520 4.27E-06
5 43800 1.07E-05
10 87600 2.13E-05
20 175200 4.27E-05
1734-IE4S
Series A Single
Channel
1 8760 2.30E-07
5.30E-11
9.402E-07 121.42
2 17520 4.70E-07
5 43800 1.20E-06 5.40E-11
10 87600 2.40E-06 5.50E-11
20 175200 4.80E-06 5.60E-11
1734-IE4S
Series A Dual
Channel
1 8760 1.60E-07
3.70E-11
9.402E-07 121.42
2 17520 3.20E-07
5 43800 8.10E-07
10 87600 1.60E-06 3.80E-11
20 175200 3.30E-06 3.90E-11