Concurrent Communication in Logix SIS
In Logix SIS, redundant controllers own the same safety I/O module via concurrent connections. Both controllers store the configuration data that you define for the I/O module. This configuration controls how the I/O modules operate in the system.
Synchronized, redundant controllers use concurrent communication to exchange safety data with remote
FLEX 5000®
safety I/O modules. A concurrent connection allows both controllers to maintain separate network paths to the same safety I/O module:- Both controllers receive safety inputs and agree on which data to use for each safety task cycle.
- Both controllers send safety outputs and cross-check to verify that the outputs match.
If a fault occurs on one of the controllers, the other controller continues to execute the safety task alone. Because the concurrent connection is already established, there is no loss of service to the safety I/O module.
For concurrent communication system requirements for Logix SIS, see the Redundancy Systems User Manual, publication 1756-UM015.
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