Rockwell Automation Allen-Bradley POINT Guard - Page 185

Rockwell Automation Publication 1734-UM013J-EN-P - July 2014 185
Safety Data Appendix D
Figure 64 - PFD vs Proof Test Interval 1734-OB8S Series B
Mission Time for all modules is 20 years.
Catalog
Number
Year Hour PFD (1/hour) PFH (1/hour) Spurious Trip
Rate (STR)
(2)
(2) Calculated based on ISA TR-84 method.
MTTFspur
(years)
(3)
(3) Mean Time to Failure (Spurious).
1734-IB8S
Series B
(1)
(1) Data for this module is for both single channel and dual channel modes of operation.
1 8760 2.18E-06 5.27E-10 2.709E-06 42.14
2 17520 4.36E-06
5 43800 1.09E-05
10 87600 2.18E-05
20 175200 4.36E-05
1734-OB8S
Series B
1 8760 2.16E-06 5.20E-10 3.243E-06 35.20
2 17520 4.32E-06
5 43800 1.08E-05
10 87600 2.16E-05
20 175200 4.32E-05