Reads values of multiple OPC-DA items.
Reads named items from an OPC-DA server or servers. Only the item values are returned (qualities and timestamps are not returned).
The ReadMultipleItemValues method requires that the quality is "good" for each item. The function performs all individual operations in parallel, but only returns after all individual operations are completed (or their timeouts elapse).
This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each item is returned in Exception property of each returned OpcLabs.EasyOpc.DataAccess.OperationModel.DAVtqResult element.
The server(s) can be local or can be remotely accessed via DCOM.
Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).
Overload List
Overload | Description |
ReadMultipleItemValues(IEasyDAClient,DAItemArguments[],DAReadParameters) | Reads named items from an OPC-DA server or servers. Only the item values are returned (qualities and timestamps are not returned). Reads multiple named item values, using item arguments objects, and common read parameters. |
ReadMultipleItemValues(IEasyDAClient,DAReadItemArguments[]) | Reads multiple named item values from a single OPC server, using array of argument objects as an input. |
ReadMultipleItemValues(IEasyDAClient,ServerDescriptor,DAItemDescriptor[]) | Reads multiple named item values from a single OPC server, using descriptor objects for the OPC server and OPC-DA items. |
ReadMultipleItemValues(IEasyDAClient,ServerDescriptor,DAItemDescriptor[],DAReadParameters) | Reads multiple named item values from a single OPC server, using descriptor objects for the OPC server and OPC-DA items, and specifying read operation parameters. |
Requirements
Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows
See Also