Problem getting correct graph data

[Thomas_V]

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

[MM_RohdeSchwarz]

Hello Thomas,

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

Milo

[Thomas_V]

for our 2012 labview we used the labVIEW 8.2 version found on this page http://www.rohde-schwarz.com/en/driver/zvl13/

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

link to custom version: http://www3.rohde-schwarz.com/www/FileTranCS.nsf/alias/ZVL_LabVIEW7?OpenDocument

[MM_RohdeSchwarz]

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

See the example if necessary.

Cheers,

Milo

[Thomas_V]

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

[Thomas_V]

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...

[MM_RohdeSchwarz]

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.

Milo

[Thomas_V]

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.

[MM_RohdeSchwarz]

Hi,

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?

Milo

[Thomas_V]

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".