Beckhoff introduces software-based control redundancy

Plant availability plays a crucial role in the process industry in particular, so building redundancy into automation technology designs is vital. To this end, Beckhoff Automation has expanded its range of solutions in this area to include a software solution for redundant control operation, known as TwinCAT Controller Redundancy (TF1100).

While the robust design of IPCs alone already provides a high level of availability, Beckhoff is expanding its product range with an entirely software-based solution that allows two standard IPCs that both run the same PLC program to operate as redundant controllers in a few steps. An additional, high-performance network connection between the two controllers provides the necessary synchronisation.

Standard Ethernet is used, so no dedicated hardware components are required. The system works in such a way as to ensure that only one of the two industrial PCs addresses the fieldbus components at any given time, and that the control programs are executed simultaneously on both computers. This synchronicity is the basic prerequisite for changing the primary industrial PC in the event of a fault, without losing any information.

In addition to controller redundancy, the well-established EtherCAT Redundancy (TF6220) software protects against failures caused by faulty cable connections. The I/O modules are connected by two separate cables, which should ideally be laid in different locations. While EtherCAT Redundancy addresses communication from the controller to the fieldbus, the TwinCAT Parallel Redundancy Protocol (PRP, TF6230) provides cable redundancy for Ethernet communication according to IEC 62439-3 to higher-level systems such as MES or decoupled HMI systems. The protocol defines a redundant and transparent network connection, which can be monitored and diagnosed in TwinCAT.