opc item not found

[cosmin]

Hello,

we have a gas chromatograph from ABB with ABB VistaNET opc server. we need to comunicate from a labview application (on a remote computer) with the opc server, but on some opc items (the alarm items) the data socket open connection return the error "OPC item not found". When we try to browse the opc server (with front panel datasocket connection) the opc items appears. We also installed server explorer on the host and the opc items are updated nicely. But in server explorer the properties tab of that items is empty! When i used the old datasocket the error returned is "Can't add item to OPC Group.  This ItemID is not known.<ERR>"

[AESulzer]

Hi there! The first step in getting at this problem is going to be to narrow down whether this is a server-side or client-side error. The best way to do this is to try other clients and severs to see where the problem follows. 

So go ahead and try to at least narrow down on which side of the communication things are breaking down and then we can continue from there. I'd also be curious which specific error codes are being returned when you experience this problem.

Kind Regards,

[cosmin]

Obviously, because majority of items can be read throught datasocket, the problem is server side. The problem appears on alarms item (whish are very important!!). The error code on datasocket open connection on that items is undefined!. I think the problem is that the server does not attach some properies on alarms items as I saw with server explorer (tab properties for an item).

[cosmin]

Can anyone help me?? The matrikon opc explorer works fine, and reads those tags. With dsc again works fine, but with datasocket I get "opc item not found".

[cosmin]

I can't get around this problem! Why is not an opc client built in labview, other that tag engine. Can anyone tell me more about the opc layer built in datasocket. Or is there a free opc client toolbox (c/c++)?

[unclebump]

I use kepware opc server. It has a quick client that can show if data is being acquired. I think you can download a time limited demo that runs for two hours.

[Sirin]

There is an OPC item browser built into LabVIEW.

Make an indicator on your screen and right click it. (Any kind of indicator will do, I normally use a numeric.)

Go to Data Operations -> Datasocket Connection...

This will bring up a dialog box. Click on Browse and Select "Browse Measurement Data..."

From there you can browse to the OPC server you are trying to talk to, and find the tags that are not connecting. When you find them, click on it, and the correct URL LabVIEW is using to find it will appear in a box at the bottom of the dialog labelled "URL".

Hope this helps.

Edit: I re-read your original message, and saw that you already did this. You might double check that the URL you're using matches the URL that the item browser shows.

Message Edited by Sirin on 07-22-2005 02:46 PM

[cosmin]

HI,
I have done everything, and I'm stuck. OPC clients from Matrikon, Iconics, Kepware, all are reading those tags. I made a simple VI-server, and the tags are read by tag engine (so if I use tag engine as opc client it works very well). But with datasocket are not (the error is undefined). If I browse the opc server with front panel datasocket connection, the tags appears!