How to continue BLE activities onto next view controller

I am developing an app which scans for nearby BLE devices, connect to one of them, and communicate to the connected device. I tried to do it in 2 view controllers, controller-A and controller-B. Controller-A would scan for nearby devices and connect to one of them. Controller-B would exchange data to the connected device. Controller-A extends CBCentralManagerDelegate. My problem is: when my app switch to view controller-B, it does not get the call-backs from CBCentralManager. I have to initialize CBCentralManager again in controller-B. I also have to disconnected the device from controller-A, and reconnect in controller-B. Is there a better way to do it? Thanks.