34
Rockwell Automation Publication 1715-RM001A-EN-P - June 2019
Chapter 4
Using 1715 Hardware in a ControlLogix SIL 2 System
Configuring 1715 I/O for SIL 2 operation
Before you can use any 1715 modules in a SIL 2 application all 1715 modules,
both adapter and I/O, must be configured for SIL 2 safety. This done by selecting
YES for ‘SIL 2 Safety’ in the module properties. If you don’t see this field, then
you do not have the proper version firmware/software installed. In addition, you
must set its connection reaction time limit (CRTL) and module requested packet
interval (RPI) and for input modules, you must configure safe state input values.
One important consideration to set is the Connection Reaction Time Limit.
This setting determines how long the connection can operate with old data
before going to its configured safe state.
For an input module, if the CRTL expires before the Add-On Instruction detects
valid data, the value of the affected input assembly transitions to the configured
safe state value. A reset is required before inputs transition from the safe state to
field values.
For an output module, if the CRTL expires before the 1715 firmware detects that
valid output data is received from the Logix controller the output data transitions
to the configured safe state values. In this case, a Reset is required before outputs
can be re-energized.
The value of the CRTL forms part of the safety considerations for the system.
You are responsible for calculating and verifying that the CRTL meets the safety
reaction time for your safety function.
IMPORTANT
See the following document for more information:
