Instrument Control (GPIB, Serial, VISA, IVI)

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cRIO VISA port forwarding

I am trying to access the Serial port of my cRIO-9067 from the host computer to program the Amulet display.  I have found the following document which is suitable for this application:


However, I would like to be able to interface other software directly over the serial port forwarded from my cRIO.  Is there any way to configure this VISA resource (visa://xx.xx.xx.xx/ASRL1::INSTR) and map it as a standard COM port on the host PC, so that any other application, not using the VISA librairies, can access it directly?  This would be useful when we connect other equipment to be able to do a direct passthrough from the Host PC to the cRIO serial port and use the manufacturer's software directly, without having to rewire anything.

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Just to clarify, you are looking for a way to include the cRIO serial port as an option when choosing serial resources on your computer. For example, you would like to be able to open up the manufacturer's software and have a drop down list or similar selection box that includes the serial port on the cRIO. Please make any corrections if I am reading your post incorrectly.

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Message 2 of 11

Exactly.  I am looking for some way to create a "COMxx" port that would really map directly to the cRIO COM port resource that is directly available through the VISA driver.  Is this readily available or would we be required to create a new driver for that?

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You might be able to do this using NI-Visa Server. talks a little about getting it up and running.



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Thanks for the suggestion. I did take a look at the VISA configuration in MAX and it looked like it was going to work for some time but in the end it failed. Here is what I did: Under MAX -> Software -> NI-VISA 14.0.1 and in the right pane My System->General Settings->Aliases, I added COM70 and linked it against "visa://" (the IP address is that of the cRIO). The result looked like on the images below. I then went into LabVIEW and the port is properly listed as COM70! Unfortunately, as soon as I try to locate that COM70 in the Device manager (or any other application), it doesn't appear. COM70 is not listed under the PC's resources. I made sure that I was logged in as Admin on the cRIO. Does any one knows what the final step would be to get that alias recognized by Windows?
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Did you make sure that NI-VISA Server is running on the PC? 

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Yes, I also tried manually starting it and the Alias that I assigned is still only visible in LabVIEW (VISA resource constant) and not in the Windows Device Manager.  Also, I have tried opening "COM70" from Putty and it also reports an error.  It is not only the Device Manager.


In your opinion, having the VISA Server enabled should allow Windows to properly discover and list it? 

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I don't think using VISA server would allow you to have the port show up from other software. VISA Server allows you to address the port by a URL (visa://<IP address>/<instrument>). If the software you are using is not using VISA, it won't be calling the resource by this URL and I wouldn't expect you to be able to choose it.


If you are unable to configure the port and reference it by the above URL, you will not be able to perform the operation you described.



Message 8 of 11

Is there an solution for this issue 4 years later?


I have a similar issue. The VISA resource (visa://xx.xx.xx.xx/ASRL1::INSTR) should be visible at the windows device manager as COMPORT, because a 3rd Party Tool (running at the host) is using this windows comport.

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Message 9 of 11

Hi ChrisPr,


Since this is an older post, you'll get more views and activity if you start a new post with your issue details.


Melanie P.
Technical Support Engineer
National Instruments
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