Creating Predefined Data Items on the DataSocket Server
You can specify data items that must be automatically created and initialized when you launch the DataSocket Server. As you create DataSocket clients, consider defining the data items in the DataSocket Server Manager so that you can define access permission groups for the data items. Complete the following steps to predefine a data item on a DataSocket Server.
- Launch the DataSocket Server Manager by selecting Start»Programs»National Instruments»DataSocket»DataSocket Server Manager. The Predefined Items category lists all items that the DataSocket Server creates each time you launch it. These items exist without DataSocket client connections, unlike dynamically created items that exist only during a DataSocket client connection.
- Click the New Item button.
- Enter a detailed description for the item in the Description textbox. For example, you might list the data source, the data type, and access permissions.
- Enter a descriptive name for the data item in the Name textbox.
- Grant read and write access to permission groups by selecting the appropriate permission group from the Read Access and Write Access pull-down menus.
- If you want to allow multiple writers to connect to the DataSocket Server, place a checkmark in the Allow Multiple Writers checkbox.
- Specify the data type and a value for the Initial Value.
Remember that predefined data items exist even without a DataSocket client connection. If a DataSocket Reader is connected to a predefined data item on the DataSocket Server before a DataSocket Writer is connected, the DataSocket Server returns the initial value to the Reader. DataSocket Writers overwrite default values; when a DataSocket Writer writes to a predefined data item, that item retains the value even if the DataSocket Writer disconnects from the server. After a DataSocket Writer overwrites the initial value of a predefined item, the item does not return to the initial value unless the DataSocket Server is shut down and relaunched.