Summary and relevant links

High availability and reliability are becoming more important in the automation technology. Even a short breakdown can result in heavy costs and security risks. The redundancy is used to guarantee plant management without any adverse effects in case of a failure and thus loss of data and associated problems do not occur.

The reliability in a redundant system with WinCC OA is implemented via hot standby. Hot standby is a hardware independent solution for high availability. This is a security concept consisting of two server systems connected with each other. Both servers are operating permanently and are subject to same functional demands (only one server is, however, always active. The second server synchronizes the data at runtime with the primary unit). If a unit fails a "flying switch" is executed and the server, which was passive until then, takes over the control. Thus, the access to data or functions is always guaranteed.