Visa Driver Error -1073807202

[FischerM16]

Hello everybody,

since 3 days I'm struggling with the following VISA error:

VISA or a code library required by VISA could not be located or loaded. This is usually due to a required driver not being installed on the system. (-1073807202)

I've connected a frequency synthesizer via USB cable to my PC with LabView (2017, 64bit) installed. I also tried with a fiber thermometer. Communication had already been established with NI MAX to both devices as I could write and read commands with the testpanel.
When trying to communicate in LabVIEW with very basic "from scratch" programming with simple VISA elements (VISA configure serial port etc.), I keep on getting the mentioned error code at the Configure Serial Port function. I already reinstalled LabVIEW and force reinstalled NI VISA 17.5. The problem keeps reappearing though.

Do you have any more ideas what might be the problem? 

Attached, I added a VI and the screenshots of the block diagram and the front panel for the thermometer communication. Com Port 4 is indicated as the device's port by both the device manager and by NI MAX.

Thank you very much for your help, I hope I didn't forget any important information.

Best

[crossrulz]

First stupid question: Where did you install to?  I found that VISA has to be installed to the C drive for some reason.

[FischerM16]

Thank you for your answer!
It was installed to C/Programs/NI/Shared. 

Is the problem perhaps that it is in a subfolder? When I wanted to reinstall VISA it did not give me the possibility to decide between installing a subfolder "shared" or not, the path is instead given as C/Programs/NI.

[crossrulz]

That is the correct location.  When I saw a similar issue it was due to somebody installing to the 😧 drive, which wreaked havoc on VISA.  I had to uninstall and reinstall into the C: drive and it was just fine.

[FischerM16]

Thank you for that piece of informtion.
Unfortunately, a wrong location of installation is not the problem then.
So do you perhaps have another idea where the problem with the serial configuration comes from?

Best

[FischerM16]

Does anybody have an idea for how to solve this persistent error? I would really appreciate it....!

Thanks

[Minions]

Your configuration uses Bytes at Port.  It may be that using the Bytes at Port is causing the issue.  Think, what happens when:

• Bytes at Port = 0 (Maybe it took a period of time greater than instantaneous to perform the function before data was ready - No wait time between VISA Write and Bytes at Port)  What is read?
• Bytes at Port = 1 (Some Data is ready, but not all of it is read)  What happens to the data that goes unread? (This time, Next time,...)
• A command is sent that does not require a response from the instrument.  What is read?

Does the instrument respond with an EOL character?  Does it use SCPI commands?  Does the instrument require a termination character to allow command interpretation?

[FischerM16]

Hi Minions,

thanks for your considerate answer. 
The VISA errors happens to appear at the VISA configure serial port, so at the very first element before anything is written or read. For this reason, I can disable the instrument property node containing the bytes at port information and it makes no difference. 

As I indicated, I can communicate without problems with NI MAX. 

The instrument responds with the answer (for example #01\s3\s243\r\n) to the query (for example ?01\s3\r) and a following ACK (*00\r\n) signal. Both, the answer and the ACK are terminated by a carriage return \r and line feed \n. As far as I understand from the programming manual, SCPI is not used. 

Because another serial device of mine has the same VISA driver error problem in LabVIEW, I deduce that the problem is within LabVIEW or the general settings, not the exact commands (NI MAX works with my commands).

Further suggestions? 🙂

Best regards

[Minions]

What is the instrument interface?  Is it a serial port is it a USB connection?  If it is a serial port, what does it specify as connections? (9600:8-N-1:No Flow)

[FischerM16]

Both of my devices communicate serially with a USB plug.

Specs:

57600 bps connection with 8 data bits, 1 stop bit, no parity and no flow control (the other device which is also not working has a baud rate of 115200).

I'm to 100% sure though that I set those parameters correctly. Correct me if I'm wrong though, please!