My recommendation is that you need some training. You didn't mention what you native tongue is, but if yoiu don't feel comfortable in English you should check online or with your local NI office for tutorials. In terms of the code you posted, the logic is seems to be manipulating the individual digital io lines to step the motor. This will work, but you need to get rid of the express VIs, in this situation they are very inefficient and may have bad side effects.
First rather than manipulating 4 individual bits, modify the code so you are working with one 4-bit port. This change will be more efficient and make it easier for you to identify logical errors in your stepping logic. What you want to do is initialize the DAQ one time outside the loop, manipulate the port outputs as needed inside the loop and then close the DAQ task when the loop finishes.
How fast are you needing to step this motor? A PC will limit your speed and is very nondeterministic in terms of response time.
Mike...
