G30
If the app is still running but you lose connection due to moving out of range, it will automatically reconnect and resume the session when you are back in range of the controller.
If the app closes or crashes during a session causing you to lose connection with the controller, once you reopen the app it will prompt you to resume the session you had in progress. If this is not the case please contact Customer Support.
You can also reconnect back to the controller and continue controlling it from the app if the connection is lost for whatever reason.
G70 and G40
Same as above. You will see the following message when you reconnect.