Using Priority Inputs without Selection Control
You are designing the audio system for a chain of pizza restaurants that play background music. Each restaurant also contains a jukebox for customer use. If a customer purchases a song, the restaurant owners want that song to play immediately—with no intervention needed by anyone. When the jukebox stops playing, the background music should fade in again.
To implement this requirement, you decide to configure the jukebox as a priority input so that when it starts playing, HAL will mute the background music, and when it stops playing, HAL will play the background music again. Because no intervention is needed, there is no need for remote control hardware (except, perhaps, to control volume).
This simple scenario requires two inputs, one for the background music and one for the jukebox. Although we are creating only one zone for this restaurant, we'll use the Distributed Program Bus for the background music. Then, if we add more zones later, the background music inputs will automatically be included in those zones.
- In the Processing Workspace, add the Distributed Program Bus to your Processing Map and configure it with one background music input.
- Add and configure the jukebox input. This input could be a RAD or an analog input.
- Optionally, customize the names of the inputs.
- From the DSP palette, click and drag a Zone Processor block into your Processing Map.
- Connect the jukebox output node to the Zone Processor input node. You do not have to connect the background music because a Zone Processor includes the Distributed Program Bus inputs automatically.
- Open the Zone Processor properties by double-clicking the block or clicking the properties icon on the block's title bar.
- Open the zone's Priority Selector block properties (using the same method as above).
- In the Priority Inputs area, click the dropdown arrow for the first item in the priority list, and then select the jukebox input.
- Specify the default channel that plays when no priority input is active. To do so, use the radio buttons to select the default channel.
- Expand the Detector Settings by clicking its arrow, and then configure any settings you like.
That's all you have to do to configure the jukebox as a higher priority input over the background music. When HAL detects a signal coming from the jukebox, it will mute the background music and play the jukebox input. When the jukebox signal stops, HAL will unmute the background music, fading it back in based on the Ramp Back value.
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