You create an OPC Historical Data Access Client object to connect to an OPC HDA server. This client lets you browse the server namespace and retrieve fully qualified IDs of each item stored on the server. You use these IDs to request historical data from the server. You can retrieve raw or processed data stored on the OPC HDA server, specifying the IDs you want to retrieve, a time period for which to retrieve data, and optional parameters. OPC Toolbox supports the following read operations:
Data is retrieved into OPC HDA Data objects, which allow you to visualize and preprocess the historical data for further analysis in the MATLAB environment. Preprocessing operations include resampling, data conversion, and data display functions.