Instrument Control (GPIB, Serial, VISA, IVI)

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VISA and virtual GPIB on Tektronix oscilloscope

Hello,

Is there any way to control a Tektronix-Windows-based-oscilloscope TDS5000 locally via NI VISA API, or the only “Open Choice” is the TekVISA?

If yes, how do I configure the "virtual GPIB" resource GPIB8::1::INSTR in MAX?

Thank you for eventual help.

Regards,

Maxim (morozov@unicas.it)

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I see that scope has been discontinued by tek.
I am not that familiar with the specific instrument, but I don't see any big problem that would prevent NI-VISA from recognizing the scope and working with it.

I don't actually know what kind of physical interface the instrument offers for connectivity with PCs. Is it an ethernet port or USB? Since you were talking about a "Virtual GPIB" resource, I guess the tek must have something different from a GPIB port to connect to.

Suggestions

  • browse to the www.ni.com/drivers page, click on the Download button to the left and search for a suitable driver for your instrument
  • browse the tek web page and see if they still offer an instrument driver for that instrument. If it is IVI compliant (look http://www.tek.com/site/sw/detail/1,1059,3482,00.html) then it is likely to have a .fp file in the driver. The .fp file is a library file that can be used directly in CVI or imported in LabVIEW (Tools>>Instrumentation>>Import CVI Instrument Driver).
  • you reported a specific resource that appears to be GPIB8::1::INSTR. This is already a VISA resource. So from LabVIEW, when browsing for VISA resources, you should see this.

AlessioD

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Dear AlessioD,

Thank you for advise.

I shall try to explain the problem with TekVISA (not only I have encountered it, see NI forums and Tek’s website) in more details:

 

1) An oscilloscope Tektronix TDS5104B (as all the series from 5000 and higher) is Windows2000-based (practically a PC with a modular digitiser). The oscilloscope software part is “TekScope.exe” application. Tektronix supplies a TekVISA API as well. When the application runs, it exposes a so-called “virtual GPIB” resource (GPIB8::1::INSTR) which is not visible by a VISA resource manager otherwise (that is when the “TekScope.exe” is off and the machine works as a PC).

 

2) In this configuration, I can transfer waveforms to other programs (from TekScope.exe to LabVIEW, for instance)  running directly on the local machine -  the scope - via the TekVISA API addressing the “virtual GPIB” (GPIB8::1::INSTR).

However TekVISA works rather poorly (especially with other resources such as a serial port), plus LabVIEW does not explain its errors (since errors of TekVISA have not been included into the respective database) and I cannot enjoy all the “cool features” of NI resource manager.

 

continues ...

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continuation

 

3) I uninstalled the TekVISA and installed NI VISA 2.6. Now the serial port works better.

What does not work is – as you have already guessed – the interface with the TekScope application. The reason: VIASA error -1073807195 : “The interface type (GPIB8::1::INSTR) is valid but the specified interface number is not configured”. It looks pretty like “no TekVISA – no virtual GPIB”.

 

4) I tried to “configure” the resource GPIB8::1::INSTR in MAX, however it is not a real GPIB, so it is not found (even when the “TekScope.exe” application runs), and I did not succeed with GPIB-VXI neither.

 

5) All other “Open Choice Solutions” offered by Tektronix (IVI driver and VXI driver, even ActiveX connection to the TekScope.exe with ProgID TekScope.TekScope.1) demand the resource GPIB8::1::INSTR.

 

6) Therefore the QUESTION arises: is there any way to control a Tektronix-windows-based-oscilloscope locally via other vendor’s VISA API (for instance NI), or the only “Open Choice” is the TekVISA?!

 

7) I believe the NI can answer this question easily since they supply various “add-ons” for the Tektronix, hence should know the problem very well (unless there are voodoo or Chinese horoscope involved).

Thank you for eventual help.

Regards,

Maxim (morozov@unicas.it)

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I believe that the virtual GPIB is a proprietary protocol that Tektronix created for their instruments so you can use LabVIEW (and others) to program on the scope or off the scope the same way. I don't know, but I thought I heard something about Tektronix making a plug-in ("passport") for NI-VISA to support their proprietary protocol. It is not something created by or supported by NI. You may want to talk to Tektronix to see if they do have a NI-VISA passport that can be installed. If so, please post the information here in case other people have a similar problem.

Thanks.
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From Tektronix’ documentation it follows that to control the scope from LabVIEW the system requires “NI-VISA 2.5 or higher or TekVISA 1.10a or higher”. Therefore I need to know how to configure the “virtual GPIB” with MAX. Now I expect a suggestion from NI.

Maxim

 

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Is the Tek documentation you're referring to for communicating to the scope from ANOTHER PC or from the Tek "PC"?  From what you've said above, it appears that you're trying to communicat via "virtual GPIB" from the Tek scope itself.  I think Tek's documentation is talking about communicating with the scope remotely, in which case NI-VISA would work just fine.  It's the "virtual GPIB" part that I'm pretty sure NI-VISA doesn't understand.  You're basically telling NI-VISA to go open GPIB8, hardware that isn't on the system.  NI-VISA has no knowledge of Tek's "virtual GPIB" setup as far as I know.  You can't configure virtual GPIB in MAX--it's a Tek thing.  Thus, I think the Tek VISA passport as GPIB Guru suggests might be a good thing to look into.
 
VISA passports are the software layers that allow VISA to understand various interface types when you pass it a resource descriptor.  Thus, theoretically, if Tek had a "virtual GPIB" passport and you enabled this with NI-VISA, NI-VISA could then talk to the virtual GPIB port.  This is a longshot--I don't know if Tek has anything resembling this.
 
Scott B.
GPIB Software
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I am almost positive that they do have an NI-VISA passport for this, but it is not installed by NI-VISA and is maintained by Tek. You likely need to contact them to obtain the passport and then it will plug-in to NI-VISA. Once you have the passport, we can help you get it working.
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Yes, I do network with the scope application locally - on the scope machine.
Tektronix' support says that "virtual GPIB" is a resource which enables to send GPIB-syntax commands via PCI bus from the DSP processor of the digitiser hardware to the system processor of the PC side of the scope. Therefore one MUST use the TekVISA, they say.
From the System>Device Manager I can actually see :
1) Tektronix IO processor
2) Tektronix PCI acquisition interface
However I don't know how it can be useful.
I have send a request regarding TekVISA passport to Tek. Waiting for replay.
Regards,
Maxim
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Hereby I would like to summarise the results of inquiry whether NI-VISA can be used on Tektronix OpenChoise (TM) Oscilloscopes.

Main Conclusion: only TekVISA can be used with OpenChoise (TM) Oscilloscopes as follows from 071130400.pdf, page 12, fig.1 (http://www.tek.com/site/mn/mnfinder_detail/1,1096,,00.html?id=2799&pn=071130400).

Another conclusion: NI couldn't, or wouldn't, help with the problem.

Regards,

Maxim

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