Greetings,
When using the NI 6024E for digital operations, you should use the CWDIO control. Since the NI 6024E only supports static (software-timed) digital I/O operations, CWDI and CWDO cannot be used. You should examine the Digital Input Example available in the following location:
C:\Program Files\National Instruments\MeasurementStudio\VB\Samples\DAQ\Digital\Digital Input
Good luck with your application.
Spencer S.