Understanding NI 9201/9221 Scanning (FPGA Interface)

To scan the channels of the NI 9201/9221, configure an FPGA I/O Node with the channels you want to acquire from the module. The channels are scanned in numerical order. They are not scanned in the order of appearance in an FPGA I/O Node.

The first time an FPGA I/O Node configured with channels on an NI 9201/9221 module executes, the NI 9201/9221 module performs two setup conversions before converting the first channel. The module stores the channel list from the most recently executed FPGA I/O Node. The module does not repeat the setup conversions for subsequent FPGA I/O Node reads that are configured with the same channel list. The module performs the setup conversions only if the channel list changes.

Refer to the Analog Input VI in the labview\examples\CompactRIO\Basic IO\Analog Input directory for an example of handling the setup conversions in the FPGA VI block diagram.

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