Allen-Bradley 1734-OB8S User Manual

208 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, all 1734-OB8S safety output channels, and
all 1734-OBV2S safety output channels must utilize pulse testing when used in
Functional Safety applications.
Catalog
Number
Proof Test Interval
(Mission Time)
PFD PFH (1/hour) Spurious Trip
Rate (STR)
(2)
(2) Calculated based on ISA TR-84 method.
MTTF spurious
(years)
(3)
(3) Mean time to failure (spurious).
Year Hour
1734-IB8S
Series B
Single Channel
1 8760 2.42E-06 5.61E-10 2.709E-06 42.14
2 17520 4.85E-06
5 43800 1.21-05
10 87600 2.43E-05
20 175200 4.89E-05
1734-OB8S
Series B
(1)
Single Channel
(1) 1734-OB8S single channel mode is only certified for functional safety applications with process safety times ≥ 600 ms or with
demand rates ≤ 1 demand per minute.
1 8760 2.02E-05 4.62E-09 3.243E-06 35.20
2 17520 4.04E-05
5 43800 1.01E-04
10 87600 2.02E-04
20 175200 4.04E-04
1734-IB8S
Series B
Dual Channel
1 8760 4.89E-07 1.20E-10 2.709E-06 42.14
2 17520 9.80E-07
5 43800 2.47E-06
10 87600 5.00E-06
20 175200 1.02E-05
1734-0B8S
Series B
Dual Channel
1 8760 4.89E-07 1.20E-10 3.243E-06 35.20
2 17520 9.81E-07
5 43800 2.47E-06
10 87600 5.00E-06
20 175200 1.02E-05
1734-OBV2S
Series B Dual
Channel
1 8760 6.45E-07 1.64E-10 2.969E-06 38.45
2 17520 1.29E-06
5 43800 3.26E-06
10 87600 6.63E-06
20 175200 1.37E-05

Allen-Bradley 1734-OB8S Specifications

General

Brand	Allen-Bradley
Model	1734-OB8S
Category	Control Unit
Language	English