The "Single Item" (SingleItem) data group enables you to read from and write to a single user-specified item ID for an OPC EIE. You can use a single item data group on an ad hoc basis from a data group editor or you can set up a UIS command that uses a single item data group.
The Transaction list drop-down box in the upper left of the data group editor only displays transactions up to the maximum number configured for the data group. Data and settings displayed in the dialog box reflect the selected transaction. FacilityID.UDC provides a means to specify a UDC to which to map the specified data item; it requires a corresponding point in the Point Service (PNT). Quality displays the OPC quality and timestamp received from the OPC server on a read request. The "Single Item" data group only reads from the device, not from the cache.
Note: The data type is fixed as vrnt for get requests to correctly capture the data type supplied by the OPC server.
The following image is an example of a Single Item data group dialog box for the OPC EIE:
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