Resolving Automatic Block Icon Tag Name Generation Failures in SIMATIC PCS 7 OS Compilation

In SIMATIC PCS 7 (v8.0, v8.1, v8.2, and v9.0), when a customized block icon in a template picture (@PCS7Typicals or @Template) fails to automatically inherit the tag name (Plant Hierarchy path + chart name + block name) during OS compilation ('Create/update block icons'), the issue is caused by a missing or misconfigured 'tagname' property in the WinCC Customized Object interface. To resolve this, open the template picture in WinCC Graphics Designer, right-click the customized object, select 'Customized Object > Edit...', and ensure that the internal static text object displaying the tag string is mapped to an exposed property named exactly 'tagname' under the 'General' property group. Additionally, verify that the 'type' property follows the exact '@BlockType/IconNumber' naming convention.

Architecture of OS Compile Block Icon Generation

SIMATIC PCS 7 features an automated mechanism that generates and links process graphic symbols—known as Block Icons—during the WinCC OS Compilation process. When an engineer places a control block (such as MonAnL, MonAnS, MotL, or VlvL) in a Continuous Function Chart (CFC), the engineering system associates the block with a WinCC faceplate and block icon.

During the OS compilation step 'Create/update block icons':
1. The OS Compiler scans all CFC charts in the Plant Hierarchy for function blocks possessing the system attribute s7_m_c = 'true'.
2. It checks the block properties for the parameter Create block icon (typically 1, 2, 3, etc.).
3. The compiler navigates to the OS project's template pictures—prioritizing @PCS7Typicals_APL<Version>.pdl, then @PCS7Typicals.pdl, and finally @Template.pdl.
4. It searches for a WinCC Customized Object whose type property matches the signature @<BlockType>/<IconNumber> (for example, @MonAnS/1 or @MonAnL/2).
5. Upon finding a matching template icon, the compiler copies the object into the target process picture (.pdl) designated by the Plant Hierarchy folder, connects all internal dynamics using the block's tag path, and writes the hierarchical tag name string directly into the object's tagname property.

Root Causes of Broken Tag Name Inheritance

When a standard library icon functions correctly but a newly created or modified block icon fails to display its tag name (leaving the text field blank, showing default placeholder text like MonAnS, or losing its link upon recompilation), the root cause lies within the WinCC Customized Object definition:

Unmapped or Renamed tagname Property: The internal text object that renders the tag name must be exposed through the Customized Object configuration interface under the literal property name tagname. If the property was named TagName, Tag_Name, or left unmapped, the OS Compiler's generation script (pdlCS.dll / Dynamic Wizard) cannot find the property and silently skips writing the tag string.
Object Created as Standard Group Instead of Customized Object: If graphics elements (rectangles, status displays, static text) are simply grouped using the standard WinCC Group command rather than converted into a Customized Object (Benutzer-Objekt), the object lacks an exposed parameter interface. The OS compiler cannot inject tag prefixes or strings into standard group objects.
Invalid type Property Syntax: The type property must adhere strictly to @<BlockType>/<IconNumber>. If the leading @ is omitted or if a space exists (e.g., @MonAnS / 1), the compiler treats the template as an invalid signature and fails to bind the hierarchical name.
Incorrect Hierarchy Directory Assignment: In SIMATIC Manager Plant Hierarchy settings, if the option 'Derive picture name from Plant Hierarchy' or 'Block icon name includes hierarchy' is altered inconsistently, the string generation algorithm truncates or discards the tag name prefix.

Step-by-Step Custom Block Icon Configuration Procedure

To configure a custom block icon in @PCS7Typicals so that tag names and tag interconnections generate automatically:

Step 1: Open the Template Picture in Graphics Designer

Open WinCC Explorer on the Engineering Station.
In the Graphics Designer file list, locate and open @PCS7Typicals.pdl (or @PCS7Typicals_APL.pdl).
Select an existing standard block icon (e.g., @MonAnS/1) and copy-paste it to create your custom variant.

Step 2: Configure the Customized Object Property Interface

Right-click the newly pasted block icon and select Customized Object > Edit....
Notice that the customized object ungroups into its constituent sub-elements (static text, status displays, extended status displays).
Select the Static Text element used to display the tag name (e.g., szTagname).
In the Graphics Designer menu, select Customized Object > Configuration Dialog....
In the Configuration Dialog:
- In the left pane, ensure the property group General is selected.
- In the center-right pane, locate the property Text belonging to szTagname.
- Drag the Text property of szTagname to the General property list in the left pane and name the exposed property attribute exactly: tagname (all lowercase).
- Locate the Customized Object base properties, and verify that the property type is exposed under General with the value set to @MonAnS/2 (or your custom type number).
- Ensure the property server_name is exposed and set to PCS7 MonAnS Control.
Click OK to close the configuration dialog, then right-click the elements and select Customized Object > Finish....

Step 3: Link Internal Dynamic Connections to Tag Prefix

Inside the Customized Object properties, verify that dynamic status displays use indirect addressing relative to the tag prefix or base tag name (e.g., .PV_Out#Value, .EventState).
Save and close @PCS7Typicals.pdl.

Step 4: Configure CFC Block Properties

Open SIMATIC Manager and locate the target CFC chart.
Double-click the block (e.g., MonAnS) to open its block properties.
In the block properties dialog, locate the field Create block icon.
Enter the matching number configured in your template (e.g., 2).
Click OK and close the CFC editor.

Step 5: Execute OS Compilation

In SIMATIC Manager, right-click the OS project and select Compile.
In the OS Compilation Wizard, select Tags and screen objects and ensure Create/update block icons is enabled.
Complete the compilation.
Open the target process picture in Graphics Designer. The custom block icon will be instantiated with its full hierarchical tag name displayed in the text field.

Customized Object Property Interface Mapping

The following parameter mapping table specifies the mandatory properties required for an APL block icon to support automated compilation:

Exposed Property NameProperty GroupInternal Object & Property SourceMandatory Value / FunctiontagnameGeneralStatic Text (szTagname) > TextEmpty in template; populated by OS Compiler with Plant Hierarchy tag pathtypeGeneralBase Object > User Property@<BlockType>/<Number> (e.g., @MonAnS/2, @MonAnL/3)server_nameGeneralBase Object > User PropertyPCS7 <BlockType> Control (identifies APL faceplate server)TagGeneralMultiple dynamic displays > TagBound to base tag path for direct process value and status readingtagStructureSystemBase Object > User PropertyStructure type identifier corresponding to the AS block typeCollectValueMiscellaneousGroup Display (GroupDisplay1) > CollectValueBound to .EventState for group alarm and warning propagation

Verification

To confirm that block icon tag names generate automatically and persist:
1. Open the target process picture in Graphics Designer following an OS compilation.
2. Select the instantiated custom block icon and open the Object Properties dialog.
3. Check the General > tagname property: It must contain the full hierarchical name (e.g., PlantSection/Unit1/CFC_Analog/MonAnS).
4. Verify that the static text visual display on the canvas renders the tag name clearly without clipping.
5. In SIMATIC Manager, rename the CFC chart (e.g., from CFC_Analog to CFC_Temp101) and run a Changes-only OS compile.
6. Re-open the process picture in Graphics Designer and verify that the block icon's tag name updated automatically to the new chart name.

Limitations and Operational Precautions

Observe the following precautions when maintaining custom block icons:
- Never Modify @PCS7Typicals Directly Without Backups: Always create a backup copy of @PCS7Typicals_APL.pdl before editing. A syntax error in template icons can disrupt block icon generation across the entire OS project.
- Project Updates and Migrations: During PCS 7 version upgrades, Siemens updates @PCS7Typicals_APL.pdl. Custom icons stored directly in standard system templates may be overwritten. Place custom icons in @PCS7Typicals.pdl or maintain a dedicated template repository picture.
- Customized Object Integrity: Never use the WinCC 'Ungroup' command on an instantiated block icon in a process picture. Ungrouping destroys the customized object interface, disconnecting faceplate invocation scripts and dynamic tag links.

Engineer FAQ

Why did the tag name appear as 'MonAnS' instead of my actual tag name?

If the block icon displays its default block type name instead of the actual instance tag name, the OS Compiler could not write to the 'tagname' property because the property was missing from the Customized Object interface or the icon was compiled as a static symbol.

Can I create multiple different icon styles for the same block type?

Yes. You can define multiple icons for a single block type by assigning different index numbers in the type property: @MonAnS/1 (compact), @MonAnS/2 (extended with bar graph), @MonAnS/3 (box view). In CFC block properties, enter 1, 2, or 3 in the 'Create block icon' field.

What does the 'server_name' property do in a block icon?

The 'server_name' property instructs WinCC which faceplate client script to invoke when an operator clicks the block icon (e.g., opening the standard APL analog monitor faceplate window).

Technical References

Related Tags

Block Icons
WinCC
Customized Object
OS Compilation
APL
SIMATIC PCS 7
Plant Hierarchy

Resolving Automatic Block Icon Tag Name Generation Failures in SIMATIC PCS 7 OS Compilation