Increasing system availability


It is possible to increase system availability by means of redundancy for applications with WinCC by using

  • redundant servers,  

  • redundant communications paths  

  • and highly available controllers.

WinCC/Redundancy gives you the option to operate two interconnected WinCC single-user systems or servers in parallel to monitor one other. You will need one of the two redundancy licenses from the delivery kit of the options package for each redundant partner server. If one of the two server computers fails, the second server assumes control of the entire system. After the failed server is operative again, the contents of all message, process value and user archives as well as internal tags are synchronized online. In all, this leads to significantly higher system availability. You production remains online, even if a server should fail.


  • Increased system availability with continuous data integrity

  • Automatic switch-over when a server fails or the S7 communication to the server fails

  • Continuous operation and visualization through automatic switchover of the clients to the intact server

  • Automatic synchronization of all archives (process value and user archives), message information and internal tags in the background after a fault is cleared

Design and functions

Normally, two WinCC stations or process data servers run completely in parallel, which means each station has its own process connection and own archives. The clients that are connected to the servers can be distributed to the servers as required, which leads to a reduced load. When one of the two WinCC stations fails, the other takes over the archiving of messages, process data and user data. This ensures complete data integrity. In client/server mode, the clients are automatically switched from the failed server to the redundant partner. This ensures continuous plant visualization and operation on every operator station.

When a failed partner is restored, all of the archived process values, messages (including statuses, acknowledgements, lists and comments), data from the user archive of the failure period and internal tags are automatically synchronized with the partner in the background – without affecting the running system. Once this is complete, two equivalent servers/stations will be available again. The clients connected to the servers are distributed among their original server partners again. The automatic switchover to the redundant partner takes place not only when a server fails, but also in case of disturbed S7 process communication or faulty applications.

Additional increase in system availability

In addition to the option of using two servers connected in parallel via the WinCC/Redundancy option, you can also design the communication channels to the controller redundantly in a WinCC application. Two communications processors are plugged in and the communication paths are doubled. The use of fail-safe SIMATIC S7 controllers can, if required, further increase availability at the control level. Combining the system solutions creates a security concept that meets even high demands.


The WinCC/Redundancy option includes licenses for both redundant servers. A Redundancy license is required on each of the two servers in addition to other necessary licenses.

Software and licenses

Article No.

WinCC/Redundancy for WinCC V7.5
License for one pair of servers (License Key for download)


WinCC/Redundancy for WinCC V7.5
License for one pair of servers (License Key on USB stick)


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