A tap is defined as a channel of data from the camera. A camera with a one-pixel output on each clock is referred to as a 1 tap camera. Some cameras output multiple pixels on the same pixel clock. If a camera outputs two pixels on the same pixel clock, it is a 2 tap camera.
The tap configuration of your camera is an important factor to consider when choosing a compatible framegrabber because the device must be able to support the pixel depth of your camera multiplied by the number of taps. Pixel depth is measured in bits.
NI framegrabbers have a data bus that is divided into 8-bit ports. Each port can hold up to 8 bits of image data. If the pixel depth of a camera is greater than 8 bits, the pixel will require the use of more than one port. Each pixel must be aligned to a port boundary.
*Note: The PCIe 1429 supports 10 tap acquisition (up to 8 bits per tap) for a pixel clock rate of 67 MHz or less.