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trouble with the connection by RS232C after installation of Labview2021

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In Labview 2020, I could control my instrument connected with RS232C (converted USB).

After I install Labview 2021, I cannot connect the instrument with RS232C.

In NI MAX, I confirmed that my PC recognize COM PORT which connects the instrument as shown in the attachment file.


But when I try to read the response from the instrument,  the time out error (VISA: (Hex 0xBFFF0015) ) occurs.

I am totally sure that I chose the right port, baud rate, data bits, stop bits, and parity. 

Judging from the fact that I connect the instrument by RS232C in Labview 2020, I think there is no problem with the connector or cable.


I would be happy if you let me know the way to figure out the present situation...

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Message 1 of 5

Did you also upgrade NI-VISA?  You will need NI-VISA 21.x for it to work with LabVIEW 2021.

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Message 2 of 5

Thank you for your reply.

I also upgraded NI-VISA.


By the way, I reported that I managed the situation by changing the RS232c cable.

I totally cannot understand this solution because the previous cable could work in Labview 2021.

Anyway, thank you.

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Message 3 of 5

@crossrulz wrote:

Did you also upgrade NI-VISA?  You will need NI-VISA 21.x for it to work with LabVIEW 2021.

Actually NI-VISA is one of the few software drivers from NI that is pretty much NOT tied to a specific LabVIEW version since its inception about 25 years ago. The entire binary bindings to NI-VISA (and NI-488.2) is completely integrated into LabVIEW and will link to whatever visa32.dll file Windows can find for LabVIEW. There might be some example files that get installed with NI-VISA explicitly that might be missing from "non-supported" LabVIEW installations but other than that, the NI-VISA interface in LabVIEW only really depends on a valid NI-VISA DLL being present anywhere in your system to be discoverable by the Windows DLL loader.


And the good news is that NI has plans to make this also more true for future DAQmx and other driver software. The very tight version coupling between drivers and supported LabVIEW software got apparently unmanageable for them too, so they finally discovered that it wasn't such a great idea after all. 😀


Obviously new driver releases will not support old LabVIEW versions back to the stone age. They will probably be limited to 2 or at most 3 versions back, just as is now. So if you want to use a new driver since it is required for a new hardware, there will be limits. But it will be possible to install drivers into specific LabVIEW versions that are the same or newer than the oldest supported driver. Nowadays if you have DAQmx 20.0 you can not install it into LabVIEW 2021 at all unless you start to do a lot of manual work by tracking down all the installed files in a LabVIEW 2020 installation and copying them to your 2021 installation manually.

Rolf Kalbermatter
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Message 4 of 5
Accepted by topic author ozizouozizou

Thank you for your reply.

Judging from recent troubles, however, I should not change the Labview version as possible as I can because I am not an expert for programming.

If I need to change the Labview version, I should buy a new PC and install the newest Labview...

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