Hot Standby CPU Redundancy Features 

For details on the configuration and operation of a Hot Standby CPU redundancy system, refer to the PACSystems 

Hot Standby CPU Redundancy User’s Manual, GFK-2308. 

▪ Supports single and redundant Ethernet remote I/O LANs through Ethernet Network Interface Unit (ENIU) 

modules 

▪ Supports simplex and redundantly controlled PROFINET remote IO (requires firmware version 8.00 or later) 

▪ Survives any one single point of failure 

▪ Bumpless switching 

o Synchronized CPUs 

o One scan switching 

o Transfer data size up to 2Mbytes; selected in CPU hardware configuration and in variable properties 

▪ Supports two redundancy communications links 

▪ Online repair of failed component 

▪ Online programming 

▪ Redundancy Memory Xchange Module 

o Manual toggle switch for role switching, which transitions control from the active unit to the backup unit 

o Redundancy status LEDs  

▪ Application-initiated role switching to switch the active unit to backup status 

▪ Redundancy status bits and message logging 

▪ Memory error checking and correction (ECC) single bit correcting and multiple bit checking 

▪ Background diagnostics