Trouble reading from FTDI FT232R chip

[Brown@KTR]

NI community, 

I am having issues reading data from an FTDI FT232R USB UART chip (in a dyno controller).  I don't have much experience with VISA or USB protocol so please forgive me if this is a trivial matter.  

I have LabVIEW 2017 installed on a desktop and on a laptop.  The desktop is running Windows 7 SP1 and the laptop is running Windows 10 Pro.  I have no issues reading from the FT232R when using the laptop but I continue to get error -1073807246 at the VISA configure serial port (The resource is valid, but VISA cannot currently access it) when using the desktop.  I bring the laptop home with me every night to program so I don't want to have to use it our test cell.  I've researched the error for the last two days but I cannot figure out why it will not work on the desktop.  I have the latest drivers from FTDI installed on the laptop and desktop.  I've uninstalled/reinstalled the drivers, tried the NI VISA driver wizard (but then saw a post from Dennis K. urging not to use that option), checked the cable, tried to figure out if the VISA resource is being use by another application on the desktop...but I just keep going in circles. 

Can anybody send me down a better troubleshooting path?  I've attached a WORD file with extra details.  I'm assuming it's a COM issue but my low level computer skills are limited. 

Thanks in advance, 

Mike   

[K C]

Hi,

Over the last (>10) years I used a lot of FTDI interface in various ways. I had some issues but not basic one like you have.

The error you tells you that another program/process is already using the COM port. Normally if you plug-in the device it will be mapped at the first not (ever) used COM port.

But is can happen that is mapped at an existing (internal) COM port.

What does the Windows device manager tells you about the COM ports ?

Kees

[Brown@KTR]

Here are some snapshots of the device manager before and after I plug in the USB cable.  The COM3 port and the USB Serial Converter both show up after the cable is plugged in (as expected).  The properties for the COM3 port are the same ones that I included in the Word file from my previous post. 

I tried changing the port to COM5 in the advanced settings but that didn't work either.  I did notice that COM4 was 'in use' in the advanced settings but not sure what that really means.

[K C]

Nothing wrong as far as I can see.

When do you get this error ? Configuration VI ?

[Brown@KTR]

Yes, when I try to run the Continuous Serial Write and Read.vi from the examples that are shipped with LabVIEW the error occurs in the 'VISA Configure Serial Port (Instr).vi'. 

As you mentioned, the possible reasons are stated as follows:

VISA: (Hex 0xBFFF0072) The resource is valid, but VISA cannot currently access it.  

I guess this isn't a LabVIEW issue but more something to do with the desktop?  The issue is that I can't seem to find which program is using/reserving the resource.  Should I just keep trying different COM ports (using the advanced settings)?  

[Brown@KTR]

Kees, 

I changed the port to COM6 in the advanced settings and now I can read the data properly. COM3 must be in use for some reason even though I can't see what's using it.    

Thank you for taking the time to reply to my posts.  Much appreciated. 

-Mike 

[Brown@KTR]

Further to my explanation in the previous post...I found the real reason why this was happening.  I'm posting it here in case someone else has the same issue and also wondering if anybody has a permanent solution to the problem.  I keep having to open device manager and disable the Microsoft Serial Ballpoint for it to work properly. 

I found this post from https://stackoverflow.com/questions/7208094/force-a-com-port-to-close.

Real issue:

"Windows identifies devices with constant data stream connected to serial port as serial mouse (in this system it was Microsoft Serial Ballpoint), and tries to install them, taking over the control over the port without any process using it. The solution is to wait for Windows to install the device (check Device Manager under Mouses And Other Pointing Devices) and then DISABLING it. If you uninstall the device it will be installed again, and the problem is back."

Changing the COM port (to 6 or 7) in the advanced settings only worked until the Microsoft Serial Ballpoint mouse decided to take over that COM port after I unplugged and then plugged the usb in again.    

Is there a way that I can fix this permanently?

Thanks