I do not know the reason yet, but here are some ideas:
- Have you used some other OPC client to check if you can get the values faster? If so, do they have Good quality initially, immediately, or does the good quality come only after some time? This can help in recognizing whether the problem is on server or client side.
- Is the problem happening only upon startup of the OPC server or the application? It may be related to startup delays, or a need for the communication to obtain initial values.
- Related to this, be aware that the ReadItemValue and ReadMultipleItemValues methods do not just read the value from the server - they also subscribe, and more importantly, they WAIT until the quality becomes "good". This is as opposed to ReadItem and ReadMultipleItems methods, which obtain the full Value-Timestamp-Quality structure and return it to your application, regardless of the quality at that moment. So, using ReadItemValue or ReadMultipleItemValues can wait much longer.
Hope this helps at least a bit.

Hello.
You need to inspect the InnerException property of the OpcException, it contains the details about about what has actually happened.
Not that if you only have license for 5.0x, you are not licensed to run 5.11. If so, this means that you actually run the trial license, and after 30 minutes you will start getting errors.

Hello,
before I can answer this, I need more information please:
- Is your system Windows Server 2003 R2, or Windows Server 2008 R2 (the last digit of the year is missing from your request)? If it is Windows Server 2003 R2, is it 32-bit or 64-bit system?
- Is your application using one of ReadItemValue/ReadMultipleItemValues method, or is it using one of ReadItem/ReadMultipleItems methods?
- When you refer to "installing version 5.0", does it mean that on the same computer, same application, same OPC server and same configurtaion, with some other version of the component, the reading was significantly faster?
- Which OPC server are you connecting to? Is installed locally or remotely?
Thank you.

From: O.
Sent: Monday, October 17, 2011 2:51 PM
To: Zbynek Zahradnik
Subject: Need your help

Hi!

I've installed version 5.0 at a client on Server 200 R2. After this the whole application is very slow. Reading an int takes up to 30 seconds.

Is version 5.0 compatible with this server version?

>Regards O.