Rockwell Automation Publication 5094-UM001E-EN-P - April 2020 191
Appendix D
Safety Data for I/O Modules
This appendix lists calculated values for probability of a dangerous failure on 
demand (PFD), average frequency of a dangerous failure per hour (PFH), and 
mean time to failure (MTTF). PFD and PFH calculations comply with 
IEC61508, edition 2, 2010.
Calculated values of PFD and PFH appear in 
Table 68 on page 192. PFD and PFH 
must be calculated for the devices within the system to comply with the SIL level 
that is required for application.
You must be responsible for following the requirements of ISO 13849-1:2015, 
to assess Performance Levels in their safety system.
You must functionally test every I/O module by individually toggling each input 
point and also verify that the controller detects it within the safety reaction time 
(SRT). Additionally, you must individually toggle each output point by the 
controller and user-verify that the output point changes state.
For more information, refer to the FLEX 5000™ safety controller manuals listed 
in Additional 
Resources on page 12.
STATUS
POWER
SAFETY DIGITAL 16 INPUT 24 VDC
5094-IB16S
5
5
TB3I
FLEX 5000
TM
 I/O
0       1       2       3       4       5       6       7       8       9       10       11       12       13       14       15