How to generate a Burst signal with Arbitrary Waveform in LabVIEW

[Giango]

Hello everybody,

I'm using LabVIEW 2018 and the digilent Waveform VI.

I'm trying to generate a short burst wave and read it with the scope. In the end it should look like this.

The yellow signal ist what I want to generate and the blue is what i want to get at the end. In the image the yellowsignal is generated with the first wavegen channel and conneted directly to the scope channel 1. The Blue signal is the second channel of the wavegen with the same Wave but this one goes trought a device i need to test and then back to the second scope channel. The first burst you can see isn't real, because if I disconete the first wavegen channel it disapiers. So the Burst will travel around 60 us i this case.

My first idea was to start the scope and then creat the burst with the wavegen turning on for a short time and off again. In my opinio this doesn't seem to be a realy good idea. What do you think?

MY second idea was to use the Arbitrary Waveform VI (DWF FGEN Configure Arbitrary Waveform) to generate the burst. But I don't realy get how to use it properly. Can somebody provide me a good example? Or is this not posible?

My first goal is to replicate the image above in LabVIEW. After that i will be working with the data of the captured waveform. In The end we will be doing multiple measurement at diferent moments and only need one burst for each point.

If you need more Information to help me, just ask. I might have forgotten something relevant.

You can ignore the difenrent amplitude for now.

Thanks.

[JColvin]

Hi @Giango,

I don't have LabVIEW 2018 so I can't readily test this, but in terms of general functionality with WaveForms, is there any particular reason for your project why you would not be able to set the AWG to start based on a trigger and run for a specified amount of time and similarly have oscilloscope be triggered by a rising edge above a certain voltage (or whatever you might reasonably expect in your situation)?

I know this all possible to do within the WaveForms software directly, though I am uncertain of what all function call are available in the VI; I do know that not all of them were ported to either VI set (link1, link2).

Let me know if you have any questions about this.

Thanks,
JColvin

[Giango]

Hello,

now I added the ad2 To olkit and made an example VI (in the attachment). But it doesn't work. I might be doing something wrong (might be a beginners misstake).

How do i use this toolkit correct?

When I stop this VI I recive this Error:

What is happening? or What have i done wrong? or How can I avoid this?

Using the Waveform toolkit everything works (at least the examples).

 

On 3/27/2020 at 11:50 PM, JColvin said:

I don't have LabVIEW 2018 so I can't readily test this, but in terms of general functionality with WaveForms, is there any particular reason for your project why you would not be able to set the AWG to start based on a trigger and run for a specified amount of time and similarly have oscilloscope be triggered by a rising edge above a certain voltage (or whatever you might reasonably expect in your situation)?

Do you mean start the scope and wait some time and then start AWG?  I think i tried this but couldn't get the timing right. Can this be done with the flat sequence or do I get timing issues with this aproach?

 

Thanks.

Scope-with-AD2-toolkit.vi

[JColvin]

Hi @Giango,

I'm not able to open your attached VI because it was made in a newer version of LabVIEW than I have available to me.

Based on these threads (link1, link2), I do not think the AD2 Toolkit is compatible with LabVIEW 2017 (and presumably newer versions as well), though I have seen the WaveForms VI set (link) work for LabVIEW 2018 though we were not able to get the graphing VI to conform to our will as per this thread.

I have attached some screenshots showing what I meant by triggering the burst signal in WaveForms with the appropriate settings highlighted. My setup was just doing a sine wave for a 5 uS, but you could instead change the WaveGen to do a different waveform (triangle, ramp, noise, etc) or change the Simple dropdown option to Custom and provide your signal of choice. The oscilloscope trigger settings also currently rely on a rising edge over 500 mV, but of course that can be adjusted to meet your design needs.

Please let me know if you have any questions about this.

Thanks,
JColvin

[Giango]

Hello @JColvin,

That might work for me. How do I implement it in Labview? which VI do I need to use? How do I have to conecte the AD2?

 

Other question:

-Is there a way to run the WaveForms application at the same time as Labview and give the comands from labview to WaveForms? This could be easier to generate the Puls I need.

-Should I use Labview version prior to 2017? I'm having the feeling that 2017 and newer are still too new to use.

-I made a VI that genreates a Wave and reads it with the scope in "one shot". Since you can't open my VI, I atteched some pictures.

There is a Digital Trigger setting in which you can select the Wavegen as trigger source, but i don't know at which level it triggers. Could you look at the VI and give me a hint on how the digital trigger works?

 

If you need more information, i can give you more.

Thanks a lot.