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Rockwell Automation Publication 1756-RM093J-EN-P - April 2018
Appendix G
Using 1794 FLEX™ I/O Modules and 1756 SIL 2 Inputs and Outputs with 1756 GuardLogix Controllers to Comply with EN 50156
Safety Functions within the
1756 GuardLogix Safety Task
Follow these guidelines for using SIL 2 and SIL 3 safety functions within the
safety task:
•
All available safety application instructions may be used.
•
SIL 3 safety input modules (that is, Guard I/O modules) may be used with
single-channel configuration for SIL 2 safety functions.
•
Use of the safety task signature and safety-locking the application is
recommended.
IMPORTANT
The safety task signature is required to operate in a SIL3 safety function.
IMPORTANT
You must not use SIL 2 data to directly control a SIL 3 output.