Historical Data Access

Access data on OPC HDA servers

Industrial Communication Toolbox™ provides an OPC HDA client that connects to OPC HDA servers. Use the client to read and interpret both raw and processed data. Alternatively, retrieve raw values and process them with OPC HDA functions in the toolbox. While working with large data sets, instructing the server to return only processed data can reduce transfer time and volume.

MATLAB^® stores all data from an OPC HDA server as an OPC HDA data object, facilitating convenient data storage, manipulation, and visualization. Each data element includes data value, quality, and timestamp associated with an item ID.

Functions

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Server Connection

`opcregister`	Install and register OPC Foundation core components
`opchdaserverinfo`	Query host for installed HDA servers
`opchda`	Create OPC historical data access client
`connect`	Connect client object to OPC server
`isConnected`	Determine if HDA client is connected to server
`disconnect`	Disconnect client object from OPC server
`opc.hda.reset`	Disconnect and delete all OPC HDA client objects
`findDescription`	Locate OPC HDA servers using server description

Server Browsing

`getNamespace`	OPC HDA server namespace
`browseNamespace`	Graphically browse OPC HDA server namespace

Read Data and Quality

`readRaw`	Read raw data of specified time range from HDA server
`readModified`	Read modified data from an OPC HDA server
`readAtTime`	Read data from an OPC HDA server at specified times
`readProcessed`	Read server-aggregated data from OPC HDA server
`opc.hdaQualityString`	converts OPC HDA quality ID to quality string

Server Items

`readItemAttributes`	Read item attribute values from OPC HDA server
`getDescription`	Get description of OPC HDA aggregate type or item attribute
`getIDFromName`	Get ID of OPC HDA aggregate type or item attribute
`getIDList`	Get IDs of all aggregate types or item attributes of OPC HDA object
`getNameList`	Get names of all aggregate types or item attributes of OPC HDA object
`getIndexFromID`	Indices matching OPC HDA data item IDs

Data Display

`opc.setDateDisplayFormat`	Set display format of timestamp for OPC data objects
`opc.getDateDisplayFormat`	Get display format of timestamp for OPC data objects
`showValues`	Display table of values for OPC HDA data object
`stairs`	Plot OPC HDA data in stairstep graph
`plot`	Plot OPC HDA data in line graph

Data Manipulation

`tsintersect`	Intersection of timestamps in OPC HDA data object
`tsunion`	Union of timestamps in OPC HDA data object
`arrayHasSameTimeStamp`	Verify if all elements in OPC HDA data object have same timestamp
`resample`	Resample OPC HDA data object to have defined timestamps

Data Conversion

`single`	Convert OPC HDA data object array to single matrix
`double`	Convert OPC HDA data object array to double matrix
`int8`	Convert OPC HDA data object array to int8 matrix
`int16`	Convert OPC HDA data object array to int16 matrix
`int32`	Convert OPC HDA data object array to int32 matrix
`int64`	Convert OPC HDA data object array to int64 matrix
`uint8`	Convert OPC HDA data object array to uint8 matrix
`uint16`	Convert OPC HDA data object array to uint16 matrix
`uint32`	Convert OPC HDA data object array to uint32 matrix
`uint64`	Convert OPC HDA data object array to uint64 matrix
`logical`	Convert OPC HDA data object array to logical matrix

Topics

About OPC Historical Data Access (HDA)

OPC Historical Data Access
Learn about the OPC HDA standard platform.
OPC HDA Objects
Learn about OPC objects for accessing an OPC HDA server.
OPC HDA Quality Values
Learn about the integrity of retrieved historical data.
OPC HDA Item Attributes
Standard attributes of OPC HDA items, including comparison of MATLAB and OPC server (COM variant) data types.

Server Connection and Browsing

Find and Connect to OPC HDA Server
Browse your network for OPC HDA servers, and browse an OPC server to find server item names.
Retrieve OPC HDA Server Namespace
Use the getNamespace function to retrieve the namespace from an OPC HDA server.

Data Retrieval and Display

Read OPC Historical Data
Retrieve data from an OPC HDA server into MATLAB.
Display Data Objects
View OPC object information in different formats.
Manipulate Data Using OPC HDA Objects
Resample to filter or convert data from an OPC HDA server.
Retrieve Large Historical Data Sets
Retrieve very large data sets from OPC historical data access servers.

Featured Examples

Install Simulation Server for OPC Examples

Install a simulated OPC server for use with the OPC examples.

Open Script

Locate and Browse OPC Historical Data Access Servers

Browse the network for OPC Historical Data Access servers, and query the server namespace for server items and their properties.

Open Script

Acquire Data from OPC Historical Data Access Server

Acquire data from an OPC Historical Data Access (HDA) server.

Open Script

Visualize and Preprocess OPC HDA Data

Work with OPC HDA Data objects.

Open Script