OPC communication loss

[stefamo]

I have a pretty simple VI that I've written that will allow data acquisition from a remote device that talks via OPC.  While initially I'm okay I loose communication, the patter seems repeatable.  I have tried some techniques with buffering but I'm not convinced this is the issue.  After I stop and restart the VI communication resumes.  I've also used server explorer but it seems to loose communication as well.  The vendor has supplied a sample OPC client and it seems to be fine.  What can I do to solve this problem?

Thanks,

[Khalid]

Server Explorer is independent of LabVIEW.  If even that isn't working correctly then the problem may not be related to LabVIEW per se. 

The vendor's OPC Client, did you try that on the same remote computer as that of LabVIEW and Server Explorer? 

-Khalid

[stefamo]

Khalid,

Unfortunately the vendors OPC client is pretty simple as well and is just intended to show how the interface could work.  So it doesn't have the capability of running from a remote machine.  What I have done was make an executible of this VI and run it on the vendor's PC but I've had the same result.

Thanks!

[Jarrod_S.]

What is the time period regarding the communication loss? How long does the VI work, and when does it fail? The original VI you posted is missing all its subVIs, which makes it difficult to examine your code. You might consider reposting...

[stefamo]

thanks for the response, i didn't realize they weren't included. 

The timing seems to be consistently timing out at 80 min.  It was suggested that I just put an internal timer in to stop the VI and restart but it seems to be circumventing the issue.  Also I think it will prevent me from programatically controling the instrument as there is a sequence of commands that must be given. 

Any thoughts on that?

Thanks,

[Jarrod_S.]

I'm not sure what's going on here. It could be a property of your OPC server or the network gets too congested.

You shouldn't have to restart the whole LV app. You could design it simply to close and reopen the connection in the event of a timeout. I'd suggest a State Machine for this.