try the "Write Dig Channel.vi" and "Write Dig Port.vi" from the examples finder and adjust the "Wait for ms multiple" value . unfortunately it seems that you can't output a pulse pattern with the DAQPad 6015. or post your code.
Best regards chris
CL(A)Dly bending G-Force with LabVIEW
famous last words: "oh my god, it is full of stars!"
Then build a 500Hz frequency source with hardware (use a 555 timer chip or 74121 logic). Use 1 of your digital outputs connected to an AND gate (7408) and connect the other input of the AND to the 500Hz source.
Digital output on= 500Hz to to stepper drive, digital output off= 0Hz to stepper drive.
~~~~~~~~~~~~~~~~~~~~~~~~~~ "It’s the questions that drive us.” ~~~~~~~~~~~~~~~~~~~~~~~~~~