Redundancy

3 types of redundancy: Select the one that fits your Mission Critical level

Type 1: Full Redundancy in Two cabinets


Full redundancy – duplication of all hardware gives a high degree of redundancy. The two CPUs are connected with a LAN cable and a serial cable. The LAN cable replicates the data, and the serial cable is a live link in case of LAN cable failure. It is only necessary to program one CPU module –  the program is automatically mirrored to the redundant CPU.


  • Advantage:  the two systems can be in separate cabinets to minimize the risk in case of a power outage, fire, lightning etc.

  • I/O is completely redundant.  In case of IO card failure, the redundant setup allows continuous operation without stop or dropout.

If this is the right solution for you, start design here

Type 2: CPU Redundancy

The ‘classic’ redundant solution. It does not give the highest degree of protection against shutdown, but it is a well know layout, as most high-end PLC / RTUs can only handle this type of redundancy. This solution mirrors data via the backplane and through the REDLINK connection. It is only necessary to program one CPU module – the program is automatically mirrored to the redundant CPU.

  • Advantage: Easily added to existing solutions – just plug in the REDLINK and the system is redundant!

If this is the right solution for you, start design here

Type 3: CPU Redundancy with shared IO

Separation of the system into 3 portions gives a higher availability. The CPUs and the shared IO can be in separate cabinets. In this type of redundant setup the CPUs scan the IO from both the left and right sides. It is only necessary to program one CPU module – the program is automatically mirrored to the redundant CPU.

  • Advantage: Can also be easily added to existing solutions
  • Gives high protection against shutdowns at a lower price and complexity than Type 1 redundancy