visa write connection has been lost

[DGU]

When I tried to use visa write, sometimes I will get an "1073807194" error on VISA write. "Connection for the given session has been lost" The only way to get rid of the error is to reboot computer, but the communication only be good for a while, then I got the same error again.
Anyone know what it means? I searched the forum, back in 2001, someone post the same question, and the solution was to install NI VISA 2.5.2 But I am using LV8, NI VISA is 3.4 now.

Thanks,

[MichaelChaney]

Hi DGU,

I'm assuming that you are using VISA to communicate over TCP/IP.  This error is indicating that a connection has been lost with the network.  You can enable or disable this keep-alive checking using a VISA property node.  Here's a link to the LabVIEW 8 Help information on how to use this:

http://zone.ni.com/reference/en-XX/help/371361A-01/lvvisaprop/tcp_keepaliveinstr/

There a few more helpful links in the Resources section of this page.  Also, here's a KnowlegdeBase entry that explains how this keep-alive property works.

http://digital.ni.com/public.nsf/websearch/072E607EE6E48AA986256F43005D2969?OpenDocument

Since rebooting fixes this issue, the problem may be with how Windows is handling this network.  Is Windows reporting that the connection is being lost?

[DGU]

I am not using it over TCP/IP. Everything is local. I have a USB to COM port device, and visa address is COM8.

Thanks,

[K C]

Hi,

Maybe this helps: http://forums.ni.com/ni/board/message?board.id=170&message.id=163370&query.id=656#M163370

(Inserting a "VISA Set I/O Buffer size" VI after the "VISA open")

Message Edited by K C on 03-24-2006 12:35 PM

[DGU]

Thank you. I will try this to see if it helps.