Data sets

Data sets can be added to a publisher and subscriber and define a list of name and value pairs that represent a list of variable values. Such variables are then represented by so-called data set fields. Meta data can be added to a data set, which provides additional information about the structure and content of a data set.

TF6105 TC3 OPC UA Pub/Sub provides two different types of data sets, which define how variables are configured and handled.

These data set types are described in more detail below.

Scope

Data sets can be configured in two different scopes: locally or globally. Local data sets are configured exclusively for a single publisher or subscriber whereas global data sets are added on device level and can be shared by publishers or subscriber, e.g. if you want to publish the same data points on two different publishers.

Data sets 1:

Global data sets can be added to a publisher/subscriber via the Data Sets tab:

Data sets 2:

In the example above the publisher has been configured with a local data set called “DsPubVars1” and a global set called “DsPubVars2”.

Data set with variables

Data sets with variables configure all variables as part of the process image. These data sets can be added either globally or locally, e.g. on a publisher:

Data sets 3:

The variables can then be added directly on the process image of the data set:

Data sets 4:

As an alternative, you can also use Copy&Paste on a variable from the PLC process image to add it to the data set, as shown in the following screenshot. Simply use STRG+C to copy the variable to the clipboard and then paste it to the target data set via the context menu.

Data sets 5:

Data set without variables

Data sets without variables do not configure the variables as part of the process image. Instead, variables can be added to the data set either via the TwinCAT Target Browser or directly from a PLC process image. The variables are then automatically linked with the corresponding symbol.

Data sets 6:

Changes to the symbol

Please note that, if the linked symbol changes, the variables need to be removed from the data set and added again via the TwinCAT Target Browser because the symbolic information is retrieved as part of the Drag&Drop process.

To add a variable to this kind of data set, please open the TwinCAT Target Browser and drag a variable to the Data Set Fields tab of the data set, as shown in the following screenshot.

Data sets 7:

The field configuration of the data set now includes the variable and it is published as soon as the configuration is activated.

Data sets 8:

Code generation

Subscriber data sets include an automatic code generation to reduce the engineering time required to create and link matching PLC variables. The code generation is accessible via the corresponding button on the subscriber data set.

Data sets 9:

This functionality generates a global variable list that contains all the variables from the subscriber data set with matching data types and the attribute “TcLinkTo” that automatically links them to their counterparts.

Data sets 10: