How to create a two pulses simultaneously using USB 6229?

[kirupacae@gmail.com]

Hello friends,

  This is Kirupasankar from India. I am Mechanical Engineer, doing automate our test rigs. In that i need to control a stepper motor through USB 6229 device and LABVIEW. I create the pulses that control the Motor. But while reverse the motor, I need to supply another pulse that has higher high time period. I am unable do that, Please help me and guide me,

Thanks and Regards,

Kirupasakar S.

[stilly32]

Hi Kirupasakar,

I'm not quite sure if I follow your question. Are you trying to generate 2 pulse trains with different duty cycles, or one pulse train with a varying duty cycle? Both can be done with the USB 6229. To get started, I would look at the "Gen Dig Pulse Train - Continuous.vi" example from Example Finder. This will allow you to generate a continuous pulse train. To create 2, simply copy the code and specify a different counter. If you want to vary the duty cycle while the generation is running, you can add a DAQmx write inside the while loop like so -

One thing to note, our counter outputs sometimes cannot source enough current to power a stepper motor - you may need to do some amplification before powering the motor itself.

Please post back if you have additional questions.

Andrew S

National Instruments

Message Edited by stilly32 on 04-06-2007 09:40 AM

[kirupacae@gmail.com]

Thanks Andrew S,

 I thank you for ur co-operation. I have a separate driver that has power to supply the stepper motor. while changing the direction of rotation i need to supply the voltage of 6-8 V. For that first i tried with analog output. But my device (USB 6229) send the voltage after stopping VI, even closing all labview programs. This is my actual problem, so i try to use pulse to avoide that. My willing is to send the analog voltage for particular time and stopped immediately.  Plase help me to do that.

I attach my VI for generating the analog voltage, Please check and give a guidance.

Once again Thank you!

Thanks and regards,

Kirupasankar S

[kirupacae@gmail.com]

Dear Andrew S,

I forgot to attach y VI in previous post. I attach with this post.

Thanks and regards,

Kirupasankar S

[stilly32]

Hi Kirupasankar,

The easiest way to ensure that your device is outputing 0 at the end of your generation is to write a waveform of 0's, wait a little bit (at least a generation period) and then stop and clear the task. This will ensure that you end on a 0, regardless of the last point generated.

Cheers,

Andrew S

Message Edited by stilly32 on 04-09-2007 08:14 AM

[kirupacae@gmail.com]

Dear Andrew,

Thanks for ur guidance. I already generate 1V output and solve my problem. I really thanking you.

Yours,

Kirupasankar S

India