Test and Measurement Forum

signal distortion of LV Example by applying arbitrary SigGen

Post your LabVIEW discussions here

signal distortion of LV Example by applying arbitrary SigGen

Postby Maik » Wed May 31, 2017 7:52 am

PicoScope 3203D is under test.
Applying the same arbitrary defined Signal via .csv file, the measured Signal generated from the LabVIEW example (PicoScope3000aExampleAWG.vi) has obvious distortion.
While the measured Signal generated from Software PicoScope is OK.
Have you also noticed this?
Attachments
PicoScope6.png
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Wed May 31, 2017 8:37 am

LVExample.jpg
By applying the same .csv defined arbitrary Signal(AWG), waveform distortion of LV Example(PicoScope3000aExampleAWG.vi) is obvious.
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Wed May 31, 2017 1:15 pm

PickUp_30032017.csv
(12.33 KiB) Downloaded 31 times
the Measurement of PicoScope6 generated Signal with PicoScope and DAQ
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Thu Jun 01, 2017 5:56 am

I am not sure as to what you are saying is the problem. The waveform shown in the first post, and data plotted from the csv file in the third post look very similar at first glance.

Do you have the file that you are loading into the waveform generator ?

Can you post a psdata file using this file and feeding it back into channel A, when using PicoScope 6.

Is the screen shot in your first post what you get when you use the waveform and feed it into a channel when using LabVIEW ?
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Thu Jun 01, 2017 7:25 am

Signal generated by .csv file using Software Picoscope6 is as defined.
In the .csv file, 1024 Points are defined. Could the sample rate of LabVIEW example the root cause? How can it been changed?
Attachments
Unbenannt.jpg
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Thu Jun 01, 2017 7:53 am

Those two waveforms look very similar to me, what do you believe is the issue with them ?

If you wish to improve the waveforms, rather than using just 1024 points I would increase this as the device has a 32kS awg waveform buffer.

If you right click on the display in PicoScope 6 and select View Properties a panel will open on the right showing exactly how the scope is set up.
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Thu Jun 01, 2017 8:25 am

PicoScope6 generated Signal is waht I expect.
However the Signal generated using LabVIEW example"PicoScope3000aExampleAWG.vi" (second screenshot) has distortion.
Can I improve the LabVIEW example to generate the same Signal as PicoScope6 does?
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Thu Jun 01, 2017 8:56 am

If you are referring to the screenshot in the second post, it may be that when you are using LabVIEW to generate the signal, you are setting the wrong frequency, and therefore it does not generate the full waveform, particularly if the horizontal time in the traces of post1 and post2 are the same.

Try changing the frequency setting and see if this has a positive effect.
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Thu Jun 01, 2017 9:21 am

Unbenannt.png
thank you for your indication.
I would like to generate the Signal with 25Hz frequency. I changed the Parameter in the LabVIEW Panel. The generated Signal remains unchanged. Have I done right?
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Thu Jun 01, 2017 10:41 am

Can you post the psdata file from PicoScope 6 where the waveform is correctly generated. I can then look at the settings and advise on how to set up LabVIEW.
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Thu Jun 01, 2017 11:27 am

Do you mean the .csv file? I defined 1024 Points in PicoScope6. I posted it in previous post.
I also tried the Signal with less Resolution to 128 Points.
The LabVIEW generated waveform is always not correct.
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Thu Jun 01, 2017 1:29 pm

No I meant the psdata file, File->SaveAs and save the current waveform, with the waveform already loaded and generating the correct signal.
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots

Re: signal distortion of LV Example by applying arbitrary Si

Postby Maik » Thu Jun 01, 2017 1:54 pm

Unbenannt.jpg
okay I see.
But the file ( > 5M) is too big to be posted here.
"The file is too big, maximum allowed size is 512 KiB."

I have just drawn the waveform in PicoScope6 exported as .csv file. Could you please import such a csv file to check?
Maik
Newbie
 
Posts: 0
Joined: Thu May 04, 2017 2:57 pm

Re: signal distortion of LV Example by applying arbitrary Si

Postby Martyn » Fri Jun 02, 2017 6:44 am

You can send it in to support@picotech.com , the psdata file contains more information that would be useful to see.
Martyn
Technical Support Manager
Martyn
Site Admin
Site Admin
 
Posts: 2819
Joined: Fri Jun 10, 2011 8:15 am
Location: St. Neots


Return to LabVIEW

Who is online

Users browsing this forum: No registered users and 0 guests