In order to make it possible for companies to implement a highly dynamic, integrated redundancy concept, Siemens came out with the fault-tolerant SIMATIC S7-400H system. The software redundancy package in combination with SIMATIC standard CPUs provides a cost-effective solution for applications with low dynamic response.

Handling, programming, configuring and communication are the same in SIMATIC S7-400H programmable controller systems as in standard systems. Redundancy-specific functions are executed by the operating system. In dependence on the network topology, redundant connections are created for use in the event of a serious problem. The switch-over to these connections is automatic and without any loss of data. The I/O modules are interfaced using redundant PROFIBUS DP lines. The fault-tolerant SIMATIC S7-400H controllers offer the new system function "redundant I/O" beginning immediately.

Software Redundancy	S7-400H
Application
The software redundancy package is excellent as cost-optimized software-based solution. It is ideal for applications with minimum dynamic. more ...	The powerful, redundant SIMATIC S7-400H programmable controllers stand for the highest reliability in time-critical applications and are ideal for highly dynamic applications. more ...
Features & Benefits
• Software redundancy package for standard   CPUs in the lower to mid-performance range (for   CPU 315-2DP or higher) • Switch-over time approx. 1s – warm standby –     no additional demands on fail safety	• Powerful SIMATIC S7-400H CPUs • Short switch-over times (< 100ms - hot standby) • Additional fail safety