This makes it possible to operate as many Powerlink devices as needed on one network with cable redundancy. The link selector function is integrated in the X20 bus controller BC8884 for connecting an X20 System. Expanding this device with two active X20HB2885 hub modules eliminates the need to wire external hubs. Two hot-swap-capable modules are required so that I/Os can continue operation uninterrupted even when a hub is replaced.B&R Industrial Automation Corp.www.br-automation.com770.772.0400