194 Rockwell Automation Publication 5094-UM001E-EN-P - April 2020
Appendix D Safety Data for I/O Modules
FLEX 5000 I/O Safety Relay
Output Module Safety Data
Tab le 70 lists the safety data for the 5094-OW4IS and 5094-OW4ISXT
modules.
Table 70 - 5094-OW4IS and 5094-OW4ISXT Digital Safety Parameter Data
Attribute
Point Operation Type
Single Channel Dual Channel
Total Failure Rate (λ (safety related)) 2.2470E-06 2.8740E-06
Safe Failure Fraction (SFF) 99.978% 99.984%
Safe Failure Rate (λS) 1.7129E-06 2.2634E-06
Diagnostic Coverage (DC) 99.909% 99.924%
Safe Detected Failure Rate (λSD) 1.71E-06 2.26E-06
Safe Undetected Failure Rate (λSU) 1.56E-09 1.73E-09
Dangerous Failure Rate (λD) 5.3388E-07 6.1058E-07
Dangerous Detected Failure Rate (λDD) 5.3340E-07 6.1011E-07
Dangerous Undetected Failure Rate (λDU) 4.8580E-10 4.6557E-10
Diagnostic Test Interval (hours) 4 4
Hardware Fault Tolerance (HFT) 0 1
Spurious Trip Rate (STR) 5.25E-06 —
Mean Time to Failure, Spurious (MTTF-spurious), (hours) 190638 —
PFH (1/hours) 4.8580E-10 4.6557E-10
PFD
AVE
, at Mission Time of 20 years 4.2556E-05 4.0784E-05
Safety Reaction Time (SRT), (millisecond) 20 20