Fail to open Serial Port

[changelopnur]

Problem Description: One C++ Software Called one DLL created by LabVIEW. The DLL is operating one MCU by COM6 on the main board of one industry computer. After end the C++ software by task manager, I start up one LabVIEW EXE to open the COM6 created with one NI official VI "VISA Configure Serial Port (Instr).vi", the following error ocurred.
Error Code: -1073807246, Source:Property Node (arg 1) in VISA Configure Serial Port (Instr).vi

1:restart the C++ software to open COM6 ok.
2:add the VISA close 2 times bofore open COM6 to LabVIEW EXE software, open COM6 failed.
3:logout the computer, use the LabVIEW EXE to open COM6 failed, the error is the same with above.
4:only after restart the computer, open COM6 ok by LabVIEW EXE software.
How can I use the LabVIEW EXE to open COM6 ok without restart the computer?LabVIEW Version: 2014(32bit), NI-VISA Runtime: 14.0.0

[PalanivelThiruvenkadam]

The Problem may be because of Serial Port not closing Properly, Make sure LabVIEW Application is Properly handled in such a way it closes the serial Port Properly whenever the application closed/Error Occurs.

Make sure no other application is accessing this Port.

For Debugging Purpose: You can confirm this issue by just unplugging and Plugging the COM6 without Restart

[RTSLVU]

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@changelopnur wrote:

Problem Description: One C++ Software Called one DLL created by LabVIEW. The DLL is operating one MCU by COM6 on the main board of one industry computer. After end the C++ software by task manager, I start up one LabVIEW EXE to open the COM6 created with one NI official VI "VISA Configure Serial Port (Instr).vi", the following error ocurred.
Error Code: -1073807246, Source:Property Node (arg 1) in VISA Configure Serial Port (Instr).vi

1:restart the C++ software to open COM6 ok.
2:add the VISA close 2 times bofore open COM6 to LabVIEW EXE software, open COM6 failed.
3:logout the computer, use the LabVIEW EXE to open COM6 failed, the error is the same with above.
4:only after restart the computer, open COM6 ok by LabVIEW EXE software.
How can I use the LabVIEW EXE to open COM6 ok without restart the computer?LabVIEW Version: 2014(32bit), NI-VISA Runtime: 14.0.0

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Ending your c++ software (whatever that means) with Task Manager does not closing the serial port properly, so LabVIEW or any other program will not be able to open the serial port.

Honestly this whole issue seems to be with your c++ software not closing the serial port properly.