Problem with connecting remote OPC Server

[ztyaner11]

Today, when I opened my labveiw 8 program which worked properly yesterday, it couldn't connect to the Items on remote OPC server anymore thought I can still browse those items in Server Explorer.  In the NI published variable monitor, quality for those items is "Server failure", Then I added a new variable which bind to a local OPC item, it works properly. What's the difference between labview8 and Server Explorer when they are used to view a OPC Item?

[Elsa Fung]

I'm not sure about the differences, but I had a Newport iSeries temperature controller and had to communicate with it through OPC.  I had the same problem as well (every now and then, the program can't communicate with the device, but I can read communicate with the device through an ie browser).  I finally got sick of it and called Newport for help, they taught me to set the number of connections through a certain port to its maximum (-> my program will get all the connection lines), and the problem never comes up again.  You might want to call your device's manufacturer and ask them if there's a limit on number of connections to the device through OPC, and how to set that number of connection.

See-Ming

[ztyaner11]

I've solved the problem,  the reason is that the NI variable engine log on as the system account, I changed it to the specified user which I used it in DCOM config, then it's ok:)

the  method is:   computer management->Services->NI variable Engine->log on->this user...