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Problem getting correct graph data

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Hello, i'm currently on an internship and I have to create an interface in LabVIEW for a Rohde & Schwarz ZVL network analyzer.


The majority of the program works like it should, only retrieving the correct graph data seems to be a problem.

I'm getting images on my screen but the data does not correspond with the data on the device.


the device is connected to the computer using a GPIB bus, we use labview 2012 and labview 7 (the end program has to be in labview 7).


I think the problem lies with the VI that retrieves the data from the machine: (rszvl sweep)




explanation of the VI: 




Here i have 2 images of the network analyzer, these images are correct and the goal is to get these on my computer in labview. (the second one is just a flat line)




Now here are a few of the creations i get in labview...






I have also attached the complete VI

Should more information be required, please ask me 


thanks in advance,

Thomas V

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Message 1 of 20

Hello Thomas,


what is the version of the ZVL LabVIEW driver you are using?



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Message 2 of 20

for our 2012 labview we used the labVIEW 8.2 version found on this page


for Labview 7 we asked for a custom version because this was no longer available at their site. 

link to custom version:

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Message 3 of 20

Instead of rszvl Get Trace Response Single Sweep use rszvl Get Trace Response with unformatted data. No math needed.

See the example if necessary.




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Message 4 of 20

ok thanks for the swift reply, i will try that now

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Message 5 of 20

thanks, now we figured out how to get the correct trace data on our graphs.


One more question, in 25% of the cases an query interrupted is generated in the trace response block and I have no idea where it comes from.

This causes the program to fail or false graphs to be generated.



I have already mailed to the rohde & schwarz support team, they tested my VI and the problem didn't occur there...

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Message 6 of 20

You get Query_interupted error if you send one query and during the waiting for the response you're sending another query or command. Use NI Spy to trace the occurence.



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Message 7 of 20

Thank you for the reply, I have tried to adjust some of the timeout settings to prevent this.

However it keeps occurring.

I have attached some of the spy files where the query interrupted shows up, would it be possible to have a quick look at them?

As we're having trouble interpreting the spy files.


Thanks in advance,

Thomas V.



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Message 8 of 20



from the NI spy log file I don't see anything suspicios. Did the program stop with error at the place where log file ended?



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Message 9 of 20

No, we've programmed it that IF the program encounters an error whilst retrieving the graph data it renews it and takes a new measurement. This works most of the time, but in about 20% of the cases it generates a "false graph".

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Message 10 of 20