All network functions are monitored continuously so that the backup controller can take over the active PLC’s functions speedily when needed. The active controller uses the same IP address as its predecessor. It takes just two task cycles – a few milliseconds – to switch from one PLC to the other.
This system makes use of the Powerlink real-time Ethernet protocol. All important data – the I/O image, for example – is synchronised continuously between the active and standby controllers via a high-speed fibre-optic link.
B&R's low-cost redundant control system uses Powerlink to connect two standard controllers
The engineering effort required to set up the redundant system consists of declaring the PLC a redundant system and configuring the communication parameters or failure criteria. The controllers can be reconfigured at any time, using B&R’s Automation Studio software to implement functions that cut downtime.
