Patent attributes
Controllers that control a building's state functions can be controlled by a master controller that the controllers choose themselves. The master controller communicates with the controllers and sensors to determine when a building state should change. When the building state should change, the master controller or another controller determines the device or devices that need to modify state values of the building, and send messages to the devices so that they can change building state. If the master controller has a fault, the working controllers can choose another master controller. When a sensor indicates that a building state needs to be changed the master controller determines which device should change state, then tells the controller that is attached to the device.
