What is the AC500 High Availability CS31 System?ΒΆ

The AC500 High Availability CS31 system is designed for the demand of automation systems that require a higher availability, which is realized by redundant devices and communications. The redundancy concept reduces the risk of losing production due to failure of parts of the automation system and thereby minimizes scheduled idle times. For instance, control can be taken over by the secondary station if the primary station fails.

AC500 High Availability CS31 system helps to implement redundancy based on standard AC500 PLCs:

  • CPU
  • Field communication
  • SCADA communication

HA-CS31 System

Greater availability to the field connection is provided by redundant Fieldbus (CS31) connection to CI590-CS31-HA, a redundant CS31 slave as S500 I/O device. The CI590-CS31-HA includes two CS31 slave interfaces: One is connected to the CS31 master system on station A, the other is connected to the CS31 master system on station B. Further information on the device is provided in the device description for CI590-CS31-HA: CI590-CS31-HA

Both automation systems require activated HA-CS31 function blocks to achieve that the control sequences can be switched over bumplessly, meaning they continue in the event of failures. The total application program has to be made considering high availability.

The HA-CS31 system has hot-standby redundancy as a quality level:

  • Both CPUs are running in parallel
  • Both CPUs are continuously synchronized
  • The fieldbus is redundant and continuously running (updated by both CPUs)
  • The CI590 remote I/O decides itself which CPU and route to trust (voter) which ensures very fast switch over times while keeping the process running.