Cannot see OPC Server items from OPC Client

[alex.]

I setup a pair of OPC Server and OPC Client.

There are many OPC items on the server. But on the client side, can only see several of them as attached

[griffindore]

Hi turbot,

It appears that your OPC Client I/O Server is connected to the National Instruments Variable Engine. In the image "OPC Client1.jpg", it appears that you are successfully viewing the I/O items of the Variable Engine. The Untitled Library 1 and Untitled Library 2 are both listed because they are deployed libraries in the Variable Engine. The NI OPC Client Status information you see available is status information of the OPC client. You see all the other deployed libraries there from what I see. You will not and should not see deployed libraries under the OPC1 directory to prevent recursion. If the OPC Client I/O Server is not connected to the Variable Manager and you should be expecting something different, please let me know. Try creating a bound shared variable (right-click library in project explorer and select create bound shared variable). See if all the items you expect are available to bind to. Thanks and have a great day!

[alex.]

I know that if I create some share libraries and bind to the OPC server on server side, after deploy it then can see the items on the client side. But since I have hundreds of libraries and will keep increasing, it will be one more job to maintain the library on the OPC server. And need to keep it uniform with other server by sourcecontrol. So I want to find out a way no need to create the libraries.

Actually what need to do is to provide an opc server, an intrerface if other systems want to connect and get info from our system.

'You will not and should not see deployed libraries under the OPC1 directory to prevent recursion', May I know why this will happen, thanks

[griffindore]

Hi turbot,

I'm a little unclear what you mean by "server side" and "client side". The Shared Variable Engine is an OPC Server. If you create an OPC Client I/O Server in the Project, that is the OPC Client. You can select "View I/O Items" on the I/O Server to view the data items that the OPC Server is hosting. No maintenance should ever be necessary on the I/O Server. If you want the OPC Server (i.e. Shared Variable Engine) to host more data items, you will have to do that yourself (i.e. deploy libraries). If you would like to access the data items via Shared Variables, any time you create more data items in the OPC Server (i.e. deploy libraries), you will need to create Shared Variables binding to those data items. DSC can easily add very many Shared Variables at once by using the "Create Bound Variables..." option and using the "Multiple Variable Editor".

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turbot wrote:

Actually what need to do is to provide an opc server, an intrerface if other systems want to connect and get info from our system.

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Since the Shared Variable Engine is already an OPC Server, the OPC Server is already provided for you. Other systems can connect to this OPC Server remotely via an OPC Client I/O Server and bound Shared Variables. Since you are using Shared Variables at both ends anyway, it would probably just be easier to bind Shared Variable to Shared Variable.

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turbot wrote:

'You will not and should not see deployed libraries under the OPC1 directory to prevent recursion', May I know why this will happen, thanks

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The I/O Server itself is deployed as part of the Shared Library (you can see it via the Variable Manager). Since your OPC Client I/O Server is connected to the Variable Engine OPC Server, you will see the I/O Server as an item in the library it is deployed. Other items that are accessible under the I/O Server are OPC Client information such as Active?, Connected?, etc. The OPC Client I/O Server itself does not physically hold the OPC Server data items and therefore those items will not be seen within the I/O Server while viewing the I/O Items of the Variable Engine. I hope this helps!

Here are some more links that may be of help:

Using OPC Client I/O Servers (DSC Module)

Accessing OPC Servers Using the DSC Module as an OPC Client (DSC Module)

Binding Shared Variables to OPC Server Data Items (DSC Module)