Data

R2026b

Access historical data retrieved from OPC UA node

Description

An opc.ua.Data object represents historical data retrieved from OPC UA nodes. When you retrieve historical values, OPC UA servers might return a different number of Value, Quality, and Timestamp arrays for each node. This data is packaged into an OPC UA data object, which allows you to process this data for common analysis tasks.

Creation

You can construct OPC UA data objects using the readHistory, readAtTime, or readProcessed functions of an OPC UA client.

Properties

Name — Name of node

Read-only: character vector

This property is read-only.

Name of the node, represented as a character vector.

Timestamp — Timestamp of retrieved node data

Read-only: datetime vector

This property is read-only.

Timestamp of data read from node, represented as a datetime vector of timestamps. Timestamps represent the time that the source provided the data to the server. The OPC UA server always returns the datetime values in the time zone of the MATLAB^® client used to retrieve the data.

Value — Value of node data

Read-only: vector

This property is read-only.

Value of data read from nodes, represented as a vector of data values. The data type of the vector depends on the data type of the node in the OPC UA server.

Quality — Quality of node data

Read-only: cell array

This property is read-only.

Quality of data read from nodes, represented as a cell array of OPC UA qualities. Each quality string indicates the major status and origin of the data value, such as 'Good (Raw)' or 'Uncertain (Interpolated)'.

Object Functions

Visualization

summary	Display summary of OPC UA data object
stairs	Plot OPC UA data in stairstep graph
plot	Plot OPC UA data in line graph
table	Convert OPC UA data object to a table

Data Operations

tsintersect	Intersection of timestamps in OPC UA data object
tsunion	Union of timestamps in OPC UA data object
arrayHasSameTimeStamp	Verify if all elements in OPC UA data object have same timestamp
append	Combine OPC UA data objects
resample	Resample OPC UA data object to have defined timestamps
filterByQuality	Filter OPC UA data by quality characteristics
getIndexFromName	Return indices of OPC data matching specified names

Type Conversion

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

Examples

Analyze Data Retrieved from Node

Create an OPC UA client and connect it to the server.

uaClnt = opcua("localhost",62550);
connect(uaClnt);

Construct a node object using index and identifier values.

uaNode = opcuanode(3,1005,uaClnt);

Retrieve data for the current day.

dataObj = readHistory(uaClnt,uaNode,datetime('today'),datetime('now'));

The retrieved data is stored in a Data object. Summarize and plot the data.

summary(dataObj);

1-by-1 OPC UA Data object:

      Name          Value           Start Timestamp       End Timestamp                Quality           
    --------  ------------------  -------------------  -------------------  -----------------------------
    Sinusoid  1000 double values  2026-03-27 00:00:01  2026-03-27 00:16:40  1 unique quality [Good (Raw)]

plot(dataObj);

Examine Properties of OPC UA Data Object

Load the sample data file and examine the properties of the first element.

load opcSampleUaData;
nodeName = uaDataSample(1).Name

nodeName =

    'Counter'

nodeValues = uaDataSample(1).Value(1:5)

nodeValues =

  5×1 int32 column vector

   0
   1
   2
   3
   4

nodeTimestamps = uaDataSample(1).Timestamp(1:5)

nodeTimestamps = 

  5×1 datetime array

   02-May-2026 11:33:09
   02-May-2026 11:33:10
   02-May-2026 11:33:11
   02-May-2026 11:33:12
   02-May-2026 11:33:13

nodeQuality = uaDataSample(1).Quality(1:5)

nodeQuality =

  5×1 cell array

    {'Good (Raw)'}
    {'Good (Raw)'}
    {'Good (Raw)'}
    {'Good (Raw)'}
    {'Good (Raw)'}

Version History

Introduced in R2015b