Serial: VISA Close on Windows generates error on Linux in LV

[waldemar.hersacher]

I have the following test environment:
Windows XP with LV 7.1.1 connected to Linux SUSE 8.0 with LV 7.1 over a serial null modem cable. Both systems use the built in serial port. VISA is always 3.1 shipped with LV 7.1.

Opening on both systems with ASRL1::INSTR sucesseds and the programs communicate with each other. When I stop the program on the Windows XP side calling VISA Close and then start it again the Linux side will generate an error. Using a serial protocol analyzer I can see the data going from Windows XP to Linux. This also occurs if I first try to send from Linux to Windows. I have to call VISA Close on the Linux side and open the port again than the communication will continue.

Replacing the Linux PC with another Windows PC does not have this problem.

You can use "Advanced Serial Write and Read.vi" from the shipped examples to do the test.

What does VISA Close do with the serial connection that Linux generates an error (0xBFFF003E)? Why does this not happen with Windows?

[LoganS]

I've been able to reproduce this problem at my machines, but do not currently have a solution, or a reason for this behavior. We are checking into it, and I will repost as soon as I have some information for you. For now, it might be in your best interest to implement some error checking to handle when that error occurs so that your application will not error out when the windows machine is disconnected.

Logan S.