Determines whether or not you want to link the I/O device to an external data source. If you link to an external data source, Citect SCADA is updated with any changes made to the external data source when a refresh is performed.

If you disconnect an existing link, you can choose to make a local copy of the tags in the data source or you can delete them from Citect SCADA's variable tags data source altogether.

The format of the data referenced by the external data source.

Specify the location of the external database. This could either be a path and filename of the external data source for the I/O device, or the IP address/directory, computer name, or URL of a data server, etc. (for example "Work.CSV" or "127.0.0.1", "139.2.4.41\HMI_SCADA" or "http://www.abicom.com.au/main/scada" or "\\coms\data\scada").

Depending on the database type selected, the browse button could:

display a standard Windows file browse dialog to browse for the external database.

display a modal dialog to browse in a tree view of servers on the network connected to the computer.

display the Unity Link Configuration Properties dialog.

Enter a connection string to provide connection details for the data source. This is similar to an ODBC connection string. For example:

UserID = XXX; Password = YYY

or

ServerNode=111.2.3.44; Branch=XXX

Not every data source requires a connection string.

Check this box if you want to insert a prefix in front of the names of linked tags in your Variable.DBF.

The prefix that will be inserted in front of the names of linked tags in your Variable.DBF (for this I/O device only). To change the prefix, delete it first, perform a manual refresh, then add the new prefix.

Determines whether the linked tags in Citect SCADA's variable tags database will be updated when the external data source is changed (i.e. you manually change a field, etc.). This refresh will occur the first time you link to the data source, and then whenever you attempt to read the changed variables (for example you compile your project, display the variable using the Variable Tags form, or paste the tag, etc.).

Without an automatic refresh, you will need to perform a manual refresh to update the linked tags in Citect SCADA.

This field controls whether or not the linked tags in Citect SCADA and an external tag database will be synchronized if either database is changed. To enable live linking, choose Yes from the Live Update menu, and verify that the Automatic refresh check box is not selected. (Live Update and Automatic Refresh are mutually exclusive.)

When Live Update is enabled and the Citect SCADA variable tag database is accessed (for example, during project compilation or when a drop-down list is populated), Citect SCADA queries the external tag database to determine if it has been modified. If so, Citect SCADA merges the changes into the local variable tag database. Conversely, any changes made to the local tag variable database will be incorporated seamlessly into the external tag database.