Tektronix TDS3012B : incorrect wave form acquirement

[haru_tank]

Hi, I'm haru_tank.

From this spring, I was assigned to a university laboratory and was tasked with measuring an oscilloscope in LabVIEW.

In my laboratory, I heard that waveform data has been taken from floppy disks so far. XD

Then, I am trying to measure the oscilloscope, TDS3012B from Tecktronix, using LabVIEW, but I cannot get the correct waveform.

In the attached vi file, I measured white noise by DC coupling.
However, the LabVIEW waveform chart shows DC voltage with no noise at all.

The time waveform saved on the floppy disk of the oscilloscope is noisy, so I think it is a problem on LabVIEW programm.

The same phenomenon occurs in an example program "Tektronix TDS 3000 Series Auto Setup waveform Acquire.vi" from the driver.

How can I get the correct time waveform data from the oscilloscope in LabVIEW?

The attached file contains vi file and the waveform data taken from the floppy disk.

Please check it.

My environment is as follows ;

• Software : LabVIEW 2018
• Oscilloscope : Tektronix TDS3012B
• I/F : GPIB-USB HS
• Driver : Tektronix TDS 3000 Series Oscilloscope
  ( http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=014E9F890ACE6DA0E0440003BA7CCD... )
  
  

Thank you for helping.

[crossrulz · Accepted solution]

I think you have a timing issue.  You are telling the oscilloscope to autosetup, which takes quite a bit of time, and then immediately ask for a waveform that it has not yet captured.  Add a delay after the setup.

You will find that this oscilloscope takes time to handle almost every command, so get used to adding delays.

[haru_tank]

Indeed, it is a timing issue.

After autoset command, I put a wait function by case structure.
Then the waveform shows correctly.

Thank you for your help!

[crossrulz]

Some advice here:

I would recommend using the Stall Data Flow.vim to add your delays.  It is in the Timing palette a little cleaner than a Wait inside of a Sequence Structure.

Five seconds seems overkill.  But I will trust you did testing to show you actually needed that long of a wait.