Siemens Industry Online Support
Siemens AG
Entry type: FAQ Entry ID: 109339757, Entry date: 02/16/2015

How do you use screen windows and tag prefixes with WinCC RT Professional (TIA Portal)?

  • Entry
  • Associated product(s)

WinCC Professional provides you with "screen windows" for configuring your automation task. This means that you can have screens of your configuration displayed as windows in other screens.
The screen windows have two important parameters: The name of the screen that includes the configuration for the operating and display elements, and a "tag prefix", which is the name of a UDT instance which contains the process data to be displayed. For example, this permits you to use a screen again in order to monitor and operate a larger number of plant sections with less configuration effort. If the plants are configured identically, you only have to change the tag prefix and then each screen window is assigned to exactly one UDT instance.

Fig. 01

This FAQ response explains how to use screen windows and tag prefixes.
The procedure is different for WinCC Professional versions up to and including V13 and V13 SP1 and higher.

Configuration for both versions
In this example you use two screen windows - "Screen window_1" and "Screen window_2", with which you monitor two identical plant sections. Both screen windows use instances of the "Insert" screen for display. The process data of the plant sections are stored in the UDTs "Left_engine" and "Right_engine", which are both of the "Demo_UDT" type. In addition, access to the global process tag "Global_control" is made from both screen windows.

  1. Create a WinCC (TIA Portal) project with one SIMATIC PC station and one WinCC RT Professional.
  2. In this project you create a screen which you configure a start screen with the name "Home", for example. The screen windows will later be in this screen.
  3. In the project library for the process data you configure a user-defined data type (UDT) named "Demo_UDT". Define "WinCC Runtime Professional" as device type for the UDT.

    Fig. 02
  4. Define the members "gauge_value" and "io_value" required for the UDT.

    Fig. 03
  5. From the pop-up menu of the UDT you select the "Release Version" command and define the properties of the released version.

    Fig. 04
    Now you can used the UDT in your project.
  6. Configure the UDT instances you need in your project - "Left_engine" and "Right_engine" of the "Demo_UDT V 0.0.1" data type - and a "Global_control" tag of the data type "int".

    Fig. 05
  7. Create another screen named "Insert". This screen is used by the screen windows in "Home".
    In "Insert" you configure the required display and operating elements like an IO field, a pointer instrument and a slide control.

Now continue configuring according to the version of TIA Portal you are using:

Further configuration in WinCC Professional (TIA Portal) up to and including V13

  1.  Link the display and operating elements from "Insert" with the corresponding process tags.
    You have two options for this:
    a) In order to use a UDT member, for "Process Tag" you enter a period "." followed by the member name, but not the name of the UDT. In the next step you define the UDT name via the tag prefix.
    b) In order to access a tag that is not assigned to any UDT you select the name of the tag and add the prefix "@NOTP::" to the name.

    Fig. 06
  2. Drag-and-drop two screen windows from the "Controls" task card palette to your main screen. Give the screen windows meaningful names like "Screen window_1" and "Screen window_2". In the inspector window under "Properties" -> "General" you link the windows with the "Insert" screen to be displayed and as tag prefix you assign each the name of the UDT instance with which you wish to link this screen instance in your screen window - in this case "Left_engine" and "Right_engine".

    Fig. 07

    The operating elements of the screen window "Screen window_1" now access the members of the UDT instance "Left_engine", those of the screen window "Screen window_2" access the members of the UDT instance "Right_engine". Both screen windows have access to the "Global_control" tag.

Now continue with the Common configuration steps.

Further configuration in WinCC Professional (TIA Portal) V13 SP1 and higher
In WinCC Professional V13 SP1 and higher you can create the links directly. Here you assign a user-defined data type to the screen which you use in the screen windows in each case. Each screen window is assigned an instance of the data type assigned to the screen.

  1. In the inspector window of the "Insert" screen you go to the "Properties" tab and under "User data type" you set the option "Use user data type". For "User data type" you select the HMI UDT defined in the library which you want to use (in this example: "Demo_UDT V 0.0.1").

    Fig. 08

    Here you define the data type used, not the instance of the data type.
  2. Link the display and operating elements of the screen with the corresponding UDT components. This is done most easily by selecting them from the drop-down list box of the tag table.
    To access a tag not assigned to any UDT you select the name of the tag and add the prefix "@NOP::" to the name. (See bottom frame in Fig. 09)

    Fig. 09
  3. One after the other you mark the screen windows you use in your configuration. In the "Properties" tab of the inspector window you select "General". Under "Contents" you enter in the "Process tag" field the required instance of the UDT which you have linked with the "Insert" screen (in this example "Left_engine" and "Right_engine").

    Fig. 10

Now continue with the Common configuration steps.

Common configuration steps

  1. Configure more operating elements on the "Home" screen as required.

    Fig. 11

In the completed configuration you can operate the UDT tags and tags either from the screen windows or from the surrounding screen (in this case with "conventional" configuration).

Fig. 12

The download includes the projects "WinCC_Prof_Screen_Windows_and_Tag_Prefixes.zap13" and "WinCC_Prof_Screen_Windows_and_Tag_Prefixes_V13_SP1.zap13" .
Open the projects with the "Dearchive..." command from the main menu of the TIA Portal.

WinCC_Prof_Screen_Windows_and_Tag_Prefixes.zip ( 1220 KB )

WinCC_Prof_Screen_Windows_and_Tag_Prefixes_V13_SP1.zip ( 1432 KB )

Further Information
Detailed information about configuring screen windows with tag prefixes in WinCC is available in Entry ID 23690358.

Creation Environment
The screens and downloads in this FAQ response were created with TIA Portal and the WinCC Runtime Professional V13 Upd. 6 and V13 SP1.

Additional Keywords
Tag prefix, Faceplate

Security information
In order to protect technical infrastructures, systems, machines and networks against cyber threats, it is necessary to implement – and continuously maintain – a holistic, state-of-the-art IT security concept. Siemens’ products and solutions constitute one element of such a concept. For more information about cyber security, please visit