A control system with redundancy is assembled as follows using the Software Redundancy package:

• Two S7-300 (CPU 313C-2 DP, CPU 314C-2 DP, CPU 315-2 DP, CPU 316-2 DP, CPU 318-2 DP or higher) or S7-400 (master and reserve, all CPUs) central controllers, can also be used in combination;
  user program and software redundancy program package on both devices
• Single-channel distributed I/O, switched, comprising ET 200M distributed I/O devices with two IM 153-2
• Redundant linking of the central controllers:
  Via MPI, PROFIBUS DP or Industrial Ethernet; existing communication links can be used.
• Optional:
  Non-redundant I/O, central or distributed
• Optional:
  WinCC operator station for user-friendly operator control and monitoring of the redundancy functions (WinCC picture block included in the supply)