For applications where reliable recording of critical data has priority, warm-standby redundancy is the preferred solution. Good support when configuring and monitoring the actual CPU redundancies helps during the rapid development of applications for which bumpless switchover is not required.
Continuous operation during maintenance, system updating and application changes is also possible in this version. If a master CPU for maintenance work is disconnected from the network, real-time processing is only affected to a minimum. The data transmission continues seamlessly and from the perspective of the receiving stations no packets are lost. The matching of process variables in the master CPU has to be resolved on the application level, which means extra effort and expense and increased complexity vis-à-vis hot-standby redundancy.
Warm-standby redundancy provides the qualities of network redundancy and the following advantages as well:
- CPU redundancy
- Switching time freely configurable (0 to 10 PLC cycles)
- Selection of the data master integrated in end points (voter), the fastest switching times possible as a result
- Diagnostic interface for monitoring and analyzing the redundancy status in the SolutionCenter
- Automatic matching of the master CPUs not integrated
➔ switchover not bumpless