Multiple measurement Tektronix DPO 3034: lag between two channels

[Jibouille]

Hi,

I try to record continuously 2 channels in the same time from the oscilloscope Tektronix DPO 3034. Nevertheless, there is a delay between my measurements which i do not want to. How can i modify my VI to avoid this kind of problem and to perfectly synchronize the 2 signals?

Labview 2013 (32bit)

Driver: Tektronix DPO MSO 2000 4000 Series

USB visa name to do this.

NI SignalExpress 2013.

I put my VI in attachment for more information.

Thank you for your help.

Jibouille

[SkyWalka]

You may be able to use a trigger to synchronize the start of these measurements.  Have you looked at the examples that came with the driver?  The example Tektronix DPO MSO 2000 4000 Series Edge Triggered Acquisition Waveform Example.vi demonstrates triggering for a waveform input.  

[Jibouille]

Hello SkyWalka,

Thank you for your advise.

I tried but nothing changed.

With or without trigger, that gives the same results.

I have put the updated version of my VI.

I really do not understand where is the problem.

Thanks for your help.

Best,

Jibouille

[Jibouille]

Hi again,

Even with the trigger, one of the two channels starts recording before the other one. That implies the observed lag in measurement.

Best,

Jibouille

[SkyWalka]

Does the Tektronix DPO3034 support simultaneous data transfer?  It may be a limitation of the device.  Take a look at this forum:

http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/Simultaneous-sampling-using-Tektronix-TDS-201...

It mentions setting a trigger for a single sample instead of continuous acquisition.

[Jibouille]

Hi SkyWalka,

I checked with the Ni Labview signalexpress 2.5.1 Tektronix edition LE and both signals are synchronized. It is then possible to have simultaneous data transfers. Nevertheless, i noticed when i used the Tektronix edition after my program that there was a lag between signals then they were back to normal after the second frame.

I also noticed that the way to record data was different. With Tektronix edition, when the screen is full, there is a transfer of data and so on. This is not the case with my program which contiously records. 

Thank you for your advice and for your help.

Best,

Jibouille