Stepper motor with a DIO

I am using a third party stepper motor and drive with a NI cRIO via a DIO NI 9381. Here, I send the 3.5v and 0V pulses to the stepper motor via a relay switch. I am facing a problem regarding the rotation of stepper motor. The stepper motor rotates in reverse direction after few steps. Please help with the error.

Hello,

We moved your post to the “Robotics and electronics discussion” section since none of the products you list are items we carry. I suggest contacting the manufacturer of your stepper motor controller for help troubleshooting. If you start your own troubleshooting, you might start by verifying your power supply can handle the load of your system.

-Derrill