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MultiCam Boards Documentation > MultiCam Documentation > MultiCam User Guide > The Channel Class > Introduction to MultiCam Channels > Switched Acquisition
Switched Acquisition

When the number of cameras connected to a board is larger than the number of available grabbers, the switched acquisition is required.

To implement the switched acquisition mode, the user will create a number of channels equal to the number of connected cameras, and assign each camera to each channel. However, the grabbers are not enough in quantity to satisfy the need of all channels simultaneously. The grabbers have to be considered as a resource common to several channels, and rules of appropriation are needed.

After the creation of channels, the application has to adequately configure them, and to activate an acquisition sequence for each channel. Subsequently, the channel becomes ready to grab images from its assigned camera as soon as the triggering conditions are met.

An acquisition phase does not necessarily occur immediately. The channel may have to wait for another channel to release the grabber. Actually, a grabber is appropriated by a channel for an acquisition phase, and, as long as the acquisition phase is running, the grabber is busy for other channels.

An acquisition sequence is, by definition, a succession of acquisition phases. Because the switched acquisition is involved, each activated channel cannot enter into an acquisition phase at any time, depending on the activity of other channels. The channel has to wait for its expected grabber to get free.

When multiple channels compete for the same hardware resources, MultiCam handles the resource allocation automatically. For more details, refer to understanding automatic switching.