LabVIEW not recognising COM ports

[seangreaney]

Hi Guys,

I've been developing a LabVIEW program on my work laptop which runs perfectly without any issues.

I am talking to an Agilent 34980A mainframe and a Brainbox USB-Serial converter via a USB hub.

I transferred an executable to the laptop which will be controlling the system and noticed that I couldn't pick up any comm ports with my VISA reference name control. I decided to open the LabVIEW developer suite on the "bad" lapop and created a simple VISA control and it didn't pick up any comms ports.

I downloaded the NI VISA software to the laptop (which took quite a while) and still I am having no joy. I upgraded from LabVIEW 2009 to 2011 (which I use) and this didn't help either. The laptop in question can read the comm ports in device manager. I just can't seem to get LabVIEW to read them.

I tried uilding an installer from the good laptop but my NI VISA seems to be hosted online rather than on my PC so I can't complete the build.

Any ideas would be appreciated?

Sean.

[Hooovahh]

Crazy question.  Do you have any COM ports on the PC?  Go to Device Manager and see what ones are listed.  Then go to MAX and see what ones are listed.  If either of these don't list your COM port, there is no hope in getting them in your application.  If they are in Windows but not in MAX then you likely don't have the VISA run-time installed and you'll need that.  You can download it, or get it off of the device drivers disks.

[seangreaneylfc]

Hi, thanks for the reply.

Yes I do have comm ports on the PC. I can see them in the device manager. I've also downloaded NI VISA to that PC but to no avail.

What I haven't tried is viewing them in MAX. I will try  that tomorrow. I can also see the COM ports in Agilent I/O Connection Expert. They are definitely there, LabVIEW just doesn't seem to pick them up.

Yet it picks them up no problem on my own PC.

[Hooovahh]

Is this "Connection Expert" running when LabVIEW is?  I'm guessing it has reserved the hardware port and won't let any other application use it.  Try with the program closed too.

[Dennis_Knutson]

You should have mentioned that you ate using Agilent software in the first place. You have a conflict with that and NI-VISA. Remove the agilent software since it serves no real purpose or make it secondary.

Viewing in MAX should have been the first thing to check.

[seangreaneylfc]

Thanks guys, I had a feeling that this might be an issue as connection expert was constantly running in the background. I will remove it tomorrow and let you know the outcome. Thanks for the help.

[seangreaneylfc]

Hi Guys,

I removed the Agilent Connection software completely and re-installed all of the necessary drivers including NI VISA runtime and this now works.

Thanks again for the help.

[Hooovahh]

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@seangreaneylfc wrote:

Hi Guys,

Thanks again for the help.

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Glad to help.  Give thanks with kudos, and marking the solution (if you are the topic creator).

[QFang]

We use Agilent hardware all the time and occasionally run into this issue.  Most of the time we don't get any problems, but it seems to be at least somewhat dependent on the install order.

I think (been a while since I did any clean installs), if you install the LV RunTime AND the VISA Run-Time FIRST, then install any/all Agilent products after, you should be good.  I have Agilent Connection Expert living "happily" next to my LabVIEW install on my development machine with no issues, but we did recently have an issue on a deployment system because I forgot to install the VISA run-time prior to the Agilent software.. The NI VISA run-time did pop up a warning about another VISA during install, I skimmed it and thought it said that it would "handle it" but at least for me it did not.  I had to go to C:\Windows\SysWOW64 (system32 if you are on a 32 bit OS) and rename the visa32.dll, then do a "repair" (or re-run) the VISA Run-Time installer from NI. 

Basically if you right-click the visa32.dll file and look at digital signatures, if it does not say National Instruments, LabVIEW won't be happy.

[seangreaneylfc]

Thanks for your input QFang. That definitely makes sense. I got a warning when installing NI-VISA too and it did say it would "handle it" by changing the name of the conflicting drivers (or something along those lines). I do have other systems running the Agilent software alongside LabVIEW and they don't have any issues so it must have been the order in which they were installed. In this system that was giving me a problem, LabVIEW was not actually installed until a later date whereas the Agilent software was there from day one.