Acquiring a Waveform of Data Using an External Channel Clock

External channel clocking is where a digital pulse train triggers the A/D conversion of each point in your channel list. Each pulse received on the channel clock input causes one analog-to-digital conversion to take place. Immediately following this conversion, the multiplexer switches to the next channel in the scan list. The A/D converter then waits for the next pulse to convert on this channel. Once all channels in the scan have been completed, the multiplexer switches back to the first channel and prepares to move through the entire scan again, until the requested number of samples have been acquired.

External channel clocking is different from external scan clocking, which triggers the board to start acquiring points from the preset list of channels. Each pulse received on a scan clock input causes the board to take another set of points from each channel in the channel list. In contrast, channel clocking causes the digital conversion of each and every point on the board. The following illustration shows the difference between channel clocks and scan clocks:





Related Links:
Read a Waveform from an Analog Input Channel Using External Sample Timing (E-series Devices)

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