Changing the direction of simple dc motor using one or max two counters

[HaroonKhan]

Hello
I am new to Labview. I was trying to run a simple linear dc motor by generating pwm using NI 9401. I have been successful in that. Now I want to change the direction of the motor digitally in the same program. I have used the second counter as well but it is also driving the motor in forward direction. How can I reverse the direction. Please help
Thanks

[Euge_Or_Pat · Accepted solution]

Hi Haroon,

The 9401 is a Digital I/O card, so you can only drive the motor in one direction unless you physically reverse the wiring.  On an analog output card, you would be able to do a negative PWM, but on a digital card you can only output a 5V Hi or Low signal which always applies the same polarity.   

To get around that you could wire the same terminals with two sets of connections, one that applies voltage to the negative terminal and one to the positive terminal to be able to drive the motor in the opposite direction.