Who do contact about a specific Labview Driver (Stanford Research SR785)

[jeff_scharpf]

oh!

Sorry Dennis I didn't mean to insult you. Now I see what you're talking about. I will look at the Querey Display function.

Thanks!

Jeff

[Dennis_Knutson]

No problem. I wasn't insulted at all. Good luck.

[jeff_scharpf]

Dennis,

Thanks alot for your help in this matter. I am frustrated with SRS because no matter what I do, I can't get an answer on how the data actually exists in the buffer when I read it.

If I assume it's bytes, as they indicate, when I use the algorithms such as the one in Querey Display, which looks like it takes every 4 bytes and converts to the IEE standard., well, when I do this, I never get the value I expect.

Also, just looking at the data, meaning, the entire array of bytes, if I look at the very last four bytes, I would think that they should represent the very last floating point number, since the SRS documentation indicates this. But when I take those bytes and try to convert them into the IEEE 754 standard, I get different results than actual.

Actual data is correct because I have noted the actual values on the isntrument, run the labview program to dl the buffer, saved the data to a binary file, then opened that file with SRS's own software. When I do that the data is correct.

So, it appears that somehow I'm not interpreting the buffer of data correctly. I've tried swapping (hibyte lobyte, etc.).

So I'm just a little frustrated. Of course this is not an NI issue. I need to get a straight answer from SRS.

Regards.

Jeff

[Dennis_Knutson]

Can you post an example of the data you are getting and what you expect it to be? Someone here may try to take a stab at it.

[jeff_scharpf]

Yes thanks!

Ok the first file is capture.dat. This is the raw binary data right off the SRS. It is 65536 READINGS. Each reading (according to SRS) is a 4 byte floating point number.

The total size of this data file is 65536 readings X 4 = 262,144  PLUS 77 bytes for header?? = total size of 262, 221 bytes.

SRS tells me that there should be a header followed by the data so I was cutting off the first 77 bytes. I'm not sure if this is correct. The bottom line is that there must be at least 262,144 bytes if I am to have 65536 floating point numbers.

The second file is capture.csv. This AFTER I use the SRS data viewer to read the above file, strip the header, and save it as an ASCII file with a CSV extension. You can see that these are actual floating point values and that there are indeed 65536 of them.

My overall goal is to read that capture.dat file into LABVIEW, and convert them into the actual readings that would result in the capture.csv. 

I can also send you the DATAVIEWER program from SRS if it helps, but it's at their website www.thinksrs.com

Thanks again for all the help!

[RSibagatullin]

Could someone provide a sample code of how to operate the SR785 from LV? I have dowloaded drivers from NI  but always get an error 1073807343.  Even I can't get the ID of SR785 using the Instrument I/O Assistant vi.  It seems that as if I am sending the commands to the wrong GPIB address even though I am using the default 10 address and made sure that my SR785 uses port 10 for GPIB  in System->Remote menu.

[Dennis_Knutson]

What is this "system remote" menu you are talking about? There is a Remote Systems item in MAX but that has nothing to do with a GPIB connection.

What is the exact VISA reference name you are using? If the instrument address is 10, then it should be GPIB0::10::INSTR and you should be able to select it in the Instrument I/O or driver by clicking on the little arrow on the right side of the resource name control. In MAX, when you did a scan for instruments, did it show up? Are you using an NI GPIB controller?

[RSibagatullin]

System-> Remote is the menu step on the SR785 analyzer.  The strange thing that it  looks like   the  "Instrument I/O Assistant" VI  does not see the analyzer because when I click on on  the  combobox to select the instrument there is no  GPIB0::10::INSTR even after I press  "Refresh insturement list" . So I entered the  GPIB0::10::INSTR  manually  and tried to write "*RST" command (RESET) but nothing happens  in the I/O Assistant.  I am using the GPIB -USB -B    and the driver from the  NI. 

[RSibagatullin]

In the I/O  instrment when I am trying to run   just  the Select instrument part from the  GPIB0::10:INSTR  this is the error that  i am getting:

Failed to open a session with the selected instrument.
   Error message : The connection for the given session has been lost.
   VISA Status code : bfff00a6

and getting slightly different error  now.

Failed to open a session with the selected instrument.
   Error message : Could not perform operation because of I/O error.
   VISA Status code : bfff003e


The instrument that i put in the combo box is  :
GPIB0::10::INSTR


Message Edited by RSibagatullin on 06-25-2008 07:12 PM

[Dennis_Knutson]

Let's start at the beginning. After you installed the GPIB software, have you gone to MAX (Measurement & Automation Software) and configured the GPIB controller? This will test the installation of the software and verify the controller can be detected. In MAX, you would then right click on the controller and select 'Scan for Instruments'. If in MAX, you cannot detect any instruments, it will do no good to try to use the Instrument I/O Assistant. In that case, you might want to review the Getting Started instructions that came with the controller or do a repair of the installation.