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Does "MMEM:TRAN? work for s2p files?

Question asked by nmedelec on Apr 29, 2014
Latest reply on May 2, 2014 by bhokkan

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Hello,
I am looking to transfer the s2p files from a PNA (eg: N5222A) into the connected PC.
My question is does "MMEM:TRAN? work with s2p files?
If it does then what is the right syntax to transfer the files using visa commands and through a GPIB.
Thank You.

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mr_matt Apr 29, 2014 11:54 AM
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From the online help (interactive manual online): http://na.tm.agilent.com/pna/help/latest/help.htm

Navigate to: programming->scpi->commands->memory->TRANsfer (or this link: http://na.tm.agilent.com/pna/help/latest/Programming/GP-IB_Command_Finder/Memory.htm#Transfer)

In that section there's a link to an example program that transfers a file to and from a PC and a PNA (a s2p file).
Here's the direct link for the example: http://na.tm.agilent.com/pna/help/latest/Programming/GPIB_Example_Programs/Transfer_Data_using_GPIB.htm
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- nmedelec @ mr_matt on Apr 29, 2014 2:59 PM
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  Thank you replying!!
  I would need some help in understanding steps 1 through 4 as per (http://na.tm.agilent.com/pna/help/latest/Programming/GPIB_Example_Programs/Transfer_Data_using_GPIB.htm) link.
  
  ! Now read the bytes coming back from the analyzer in four steps
  138   ! (1) Read and dump the first character - '#'
  140   ENTER @Na USING "#,A";A$
  141   !
  142   ! (2) Read the next character which is the number of digits in the file size
  150   ENTER @Na USING "#,A";Digit$
  160   !
  161   ! (3) Use the value of the number of digits to read back the file byte size
  170   ! Create query string using this number of digits
  180   Img$="#,"&Digit$&"A"
  190   !
  200   ! Byte$ holds the number of bytes in string format
  210   ENTER @Na USING Img$;Byte$
  220   !
  225   ! (4) Read the file contents into a buffer and store the buffer contents to a local file
  230   ! Allocate a buffer for holding the data
  240   ALLOCATE Dat$[VAL(Byte$)]
  250   !
  260   ! Set up a different image for filling the buffer
  270   Img$=Byte$&"A"
  280   !
  290   ! Retrieve the actual file data
  300   ENTER @Na USING Img$;Dat$
  305   !
  
  I am not sure of what programming language this is. I did try only the MEMM:TRAN? command with the filename and it does not work.
  I am confused as to even if transferred then where would it save on the PC.
  
  Looking forward any help.
  Thanks!
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  - drkirkby @ nmedelec on Apr 30, 2014 9:31 AM
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    > {quote:title=nmedelec wrote:}{quote}
    > Thank you replying!!
    > I would need some help in understanding steps 1 through 4 as per (http://na.tm.agilent.com/pna/help/latest/Programming/GPIB_Example_Programs/Transfer_Data_using_GPIB.htm) link.
    
    > I am not sure of what programming language this is.
    
    I don't have a PNA, but clicked the link to see for myself. I did not reconsise the language either, but it does say at the top
    
    "The following RMB examples ..."
    
    A Google shows up various things, but the most promising looking seems to be "Rocky Mountain BASIC"
    
    http://en.wikipedia.org/wiki/Rocky_Mountain_BASIC
    
    Give me C any day!!! I am not saying it is Rocky Mountain BASIC, and rather unhelpfully the Wikipedia page does not have any example code, but I suspect that is what it is.
    
    Hopefully one day I will have to program a PNA-X. For now I have to make do with my 8720D, which I program in C.
    
    Dave
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mr_matt Apr 30, 2014 6:52 AM
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You'll need to look into explanations and examples in the manual.

About GPIB:
http://na.tm.agilent.com/pna/help/latest/Programming/Learning_about_GPIB/Learning_about_GPIB.htm

Example programs:
http://na.tm.agilent.com/pna/help/latest/Programming/GPIB_Example_Programs/SCPI_Example_Programs.htm
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mr_matt May 1, 2014 7:45 AM
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I does appear to be rocky mountain basic, as drkirkby says. However, the SCPI commands within that code are still applicable in other languages (the method in which you send the specific commands differs).

As you read this, reference the help file for the MMEM:TRAN command: http://na.tm.agilent.com/pna/help/latest/Programming/GP-IB_Command_Finder/Memory.htm#Transfer

The data transfer works like this:
You know a file is located in the default directory of the PNA (and you know the name), and you want to get the file to the PC.

You need to send a request to the PNA to retreive the file for you. So you send the following command: MMEM:TRAN? "myfile.s2p"
notes: the quotation marks are required (I just tried), and myfile should be replaced by your filename. On my PNA, the default file location is c:\Program Files\Agilent\Network Analyzer\Documents (which is the first place that pops up when I choose File->Save As in the PNA UI screen).

Next you will start getting back data from the PNA. There is some important information at the beginning of the data stream telling you how large the file is. The rocky mountain basic code shows you how to parse this information. Then you will need to save the data streaming back from the PNA into a file (the file isn't automatically created for you on the PC).

On my PNA when I read back the first few bytes, I see: #512007!
The # symbol demarks the beginning of the message
The 5 tells you that the file size will be represented by the next 5 bytes
The 12007 tells you the file size to expect (if I find the file test.s2p, right-click and look at properties, the size is reported as 12007 bytes)
and the ! tells you that you're at the end of that piece of information.

After that the contents of the file come next. So, this means that you need to save 12007 bytes that follow the ! symbol into a file. Since it looks like the contents of a s2p file are text, you can save to a text file (opposed to binary).
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- bhokkan @ mr_matt on May 2, 2014 4:06 AM
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  Nice description, mr_matt. All that you said is correct, except that the first byte that comes after those digits (the 12007 in your case) is always actually the first byte of the file's contents (a '!' in the case of an s2p file). You read those 12007 bytes which includes the ! in your case, and then I believe the analyzer also tacks-on a trailing linefeed character (ASCII decimal value 10) at the end because the analyzer traditionally does that to signify the termination/end of a query response.
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