ReadItem Method (IEasyDAClientExtension)

Reads an OPC-DA item. Value, quality and timestamp are returned.

The ReadItem method reads the data of an OPC-DA item. It uses the first available data from the server; it does not wait until the quality becomes "uncertain" or "good".

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
ReadItem(IEasyDAClient,DAItemArguments,DAReadParameters)	Reads a named item using an item arguments objects, and read parameters. Value, quality and timestamp are returned.
ReadItem(IEasyDAClient,DAReadItemArguments)	Reads a named item using an object that holds all necessary arguments. Value, quality and timestamp are returned.
ReadItem(IEasyDAClient,ServerDescriptor,DAItemDescriptor)	Reads a named item using descriptor objects for the OPC server and OPC-DA item. Value, quality and timestamp are returned.
ReadItem(IEasyDAClient,ServerDescriptor,DAItemDescriptor,DAReadParameters)	Reads a named item using descriptor objects for the OPC server and OPC-DA item, and specifying read parameters such as the data source or value age. Value, quality and timestamp are returned.
ReadItem(IEasyDAClient,String,String,String,VarType)	Reads a named item using individual parameters specifying its location, and a specific data type.
ReadItem(IEasyDAClient,String,String,String,VarType,Int32)	Reads a named item using individual parameters specifying its location, a specific data type, and value age. Value, quality and timestamp are returned.
ReadItem(IEasyDAClient,String,String,String)	Reads a named item using individual parameters specifying its location, and using server's canonical data type. Value, quality and timestamp are returned.

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

Reference

IEasyDAClientExtension Class
IEasyDAClientExtension Members

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