Trouble recalling saved states in Rohde & Schwarz ZVR VNA through Labview

[vivek.madhavan.13]

Hello,

I am working on automating some network analyzer measurements. I am using the ZVR network analyzer from Rohde & Schwarz and I am communicating with the instrument through GPIB. One of the measurements requires me to recall some manually saved calibration data.

I have been using the SCPI command to load/recall the saved calibration data which is given in the operating manual of the ZVR VNA as "MMEMory:LOAD:STATe 1, <file_name>", but the instrument does not seem to load/recall this saved calibration data. Also, labview does not give an error at the end of the program. When I try manually recalling the saved data, I am able to do this without any glitch.

What could be the possible reason for this VNA to not respond to this command? I would really appreciate any comments in this regard.

Thank You,

Vivek

[Poolean]

Hi Vivek,

When you say you’re “manually recalling the saved data” how are you accomplishing this task?

Are you able to communicate with the device via a test panel in NI Measurement & Automation Explorer?

Also, if you post a picture of the code you’re working with, it’d be helpful in trying to troubleshoot this issue.

Mike

[vivek.madhavan.13]

Hi Mike,

Thank you for getting back to my query. Yes, I am able to communicate with the instrument using NI MAX. It does respond to the *IDN? query, in fact it performs all the other tasks like getting the trace data onto the computer etc.

I have actually saved some through line calibration data for different cables which I would like to load/recall at different instances during the measurement.

By 'manually recalling the data', I mean pressing the buttons, RECALL--> EDIT NAME--> {FILE NAME}--> ENTER, in the instrument local mode to load/recall the particular calibration setting. This way I am able to recall/load the calibration setting but my measurement would require this to be automated.

I have attached a pic of the snippet that has not been functioning properly. The command I have used is equivalent to pressing the above mentioned buttons but, for some reason I am not able to get it to recall the calibration settings through the code.

Thanks again,

Vivek

[Poolean]

Hi Vivek,

Try running the example in the NI example finder under: Hardware Input and Output>>VISA>>GPIB and VISA functions.vi

Attempt the *IDN? query with this example, and, if that works, try substituting your command to load the old calibration setting.

Mike

[vivek.madhavan.13]

Hi Mike,

I went through the Hardware Input and Output>>VISA>>GPIB and VISA functions.vi and had to make a couple of small changes in the SCPI commands as my instrument does not recognize the already existing codes. I have attached the screen shot of the GPIB and VISA functions.vi block diagram and front panel as it is.

I have also attached the screen shot of the block diagram and front panel of the modified 'GPIB and VISA functions.vi' code  that performs the *IDN? query. It responded to the *IDN? query as can be seen from the front panel.

But when I tried substituting the *IDN? query with the command to recall the calibration settings, it did not work. I have again attached the screen shot of the block diagram and front panel of the code I used for this purpose. Please note that here I had to remove the VISA read block as well, as there is nothing to be read while recalling the settings.

Thanks,

Vivek

[Poolean]

Hi Vivek,

Please perform an I/O Trace Capture of the calibration command and post the results.

This should tell you if the device is accepting your command or not.

If you are unfamiliar with how to perform the trace, the process is described in this knowledge base article: http://digital.ni.com/public.nsf/allkb/282C5D41E2BA04F2862574BA007803B9

Mike

[vivek.madhavan.13 · Accepted solution]

Hi Mike,

I happened to contact Rohde & Schwarz to confirm that the SCPI command that I have been using is the appropriate one and I came to know that, though my SCPI command was the right one the format was wrong and so the instrument did not respond to the command. The correct command would be "MMEM : LOAD : STAT 1,'filepath\file_name.CFG'" where filepath would be in DOS format and a .CFG extension needs to be appended to the file name. For some reason, the file name format and extension to be used is not mentioned in the R&S operating manual resulting in the confusion.

Now the issue has been resolved and the VNA is working absolutely fine. I appreciate your time in helping me get to the solution.

Thanks again,

Regards,

Vivek

[Poolean]

Vivek,

I'm happy to help. Glad to hear that you're up and running!

Mike