How are you using the DAQmx Create Task.vi? Are you using it to include a global channel or copy a task that was previously created in Measurement and Automation Explorer (MAX)? If this is the case the only way to remove a channel would be to delete the global channel or modify the physical channels for that task in MAX. If you are creating a new task you can use the DAQmx Create Channel.vi to specify the physical channels that you would like to include or exclude.
Regards,
Andy F.
Applications Engineer
National Instruments
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National Instruments