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Member
MissFitt
Posts: 78
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hifrequency,

 

You will need two wires so you can connect the one to the AO pin and the other will be connected to AO ground to complete the circuit. If you look at the pin diagram on the specification sheet above, you will see which pins they are. Also, you won't need to solder the pin, you should be able to just screw it in. 

 

LabVIEW 2011 is available on our website found here. As long as you download LabVIEW first, and then download the drivers, you should be able to communicate with the HP unit. Thanks!

 

Mychal F

Applications Engineer
National Instruments
Member
Hifrequency
Posts: 10
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hello Mychal,

 

Thanks for your help again.

 

I did order the cables, which will arrive soon.

 

However, I wanted to know if purchasing LabVIEW sudent edition 2011 is a viable option or not.

At the moment I do think I would like to invest in LabVIEW student edition.

 

Thanks.

 

Member
MissFitt
Posts: 78
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hifrequency,

 

LabVIEW Student Edition 2011 is available for students with an edu account. You can navigate to the purchasing page from this website. 

 

Mychal F

Applications Engineer
National Instruments
Member
Hifrequency
Posts: 10
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Mychal,

 

According to this link, the LabVIEW support drivers for interfacing with HP 33XXX units is available for download only for the 2009, 8.2 editions.

 

http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=0470714759413BCCE0440003BA7CCD...

 

If I purchase LabVIEW 2011 would the drivers that I download from the above link be compatible?

 

Is there a backward/forward compatibility or do I have to request a new interfacing driver for 2011?

 

Please let me know. Thanks.

Member
MissFitt
Posts: 78
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hifrequency,

 

I downloaded the driver from this site and was able to use it in my LabVIEW 2011. 

 

Mychal F

Applications Engineer
National Instruments
Member
Hifrequency
Posts: 10
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hello Mychal 

 

I bought the student version of Labview 2011 and tried building a few VI's myself. 

It was quite easy because of the tutorials. 

 

However, now I am trying to connect my DAQmx hardware to the Labview program and I don't know how to do it.

 

I am attaching over here a sweep VI demo picture, which I used for generating a sweep signal.

However, now how do I drive my DAQmx using this sweep VI program? 

 

Sweep Demo

Member
MichaelAE
Posts: 71
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hey Hifrequency,

 

You’re going to want to use DAQmx in LabVIEW to communicate with your USB 6251. Here’s a link for how to get started with DAQmx.

You’ll want to get your device to show up in Measurement and Automation Explorer(MAX). Once you’ve got that, you can place a DAQ assistant on the block diagram and use that to communicate with your device. If the DAQ assistant doesn’t provide enough functionality, you’ll want to look into the Getting started with DAQmx programming link.

 

Regards,

Michael M

NI Americas | AE

NI.com/support | 1866-275-6964



Member
Hifrequency
Posts: 10
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hello

 

I am now able to communicate with DAQmx device USB 6251 using the following code

 

Capture_NI_1.PNG

 

 

and modulate the signal in my HP unit. 

 

However, I would now like to modulate a chirp/sweep signal. 

 

I was wondering whether I can replace this sine generation function in this above code

 

Capture_NI_2.PNG

 

with this timed sweep.vi? 

 

 

 

 

 

Capture_NI_3.PNG

 

Please let me know how to get chirp/sweep data out of my daqmx device. Thanks a lot for your help! 

 

Regards

Member
Hifrequency
Posts: 10
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hello

 

I have tried using the timed sweep vi from examples by integrating with the continuous waveform generation vi. Here is a screenshot of the code

 

 

Capture_NI_6.PNG

 

 

The labview code runs alright without any errors and it also shows the desired chirp/sweep on the labview waveform graph when I run it.

 

However, when I try to output this waveform to say an oscilloscope, it does not show the chirp/sweep.

I thought may be the oscilloscope is not good, so I tried using my previous code to output a simple sine wave and that works!

 

I believe that the DAQmx device is not outputing the chirp/sweep because the code for chirp/sweep is incorrect.

 

Please help me.

 

Thanks 

Member
MichaelAE
Posts: 71
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Re: How can I generate high frequency signal from NI USB 6251 and modulate that using HP AM modulation unit?

Hi Hifrequency,

 

I’m glad you got the Cont Gen Voltage Wfm-Int Clk.vi to work.

You’re going to want to make sure that you’re inputting the proper type into the DAQmx write. You want a 1-D array of Waveform (doubles) for NChanNSamp.

 

The Example with the Timed Sweep VI seems to only be using a single channel. Is this the channel you are measuring?



Regards,

 

Michael M

NI Americas | AE

NI.com/support | 1866-275-6964