Why APL Interlock Faceplate Buttons Are Disabled on WinCC OS and How to Fix Them

When interlock jump buttons on Advanced Process Library (APL) motor and valve faceplates appear disabled (grayed out) on a WinCC OS station—despite working perfectly during test runs on the Engineering Station (ES)—the fault is caused by missing internal text references in the WinCC Text Library or corrupted local OS project directories. In APL faceplates, clicking an interlock button jumps directly to the linked interlock block (Intlk02, Intlk04, Intlk08). This navigation relies on an internal system tag (<HID><CFC>/<Block>.Interlock#Jump) that queries an index in the WinCC Text Library. If an OS project is compiled or downloaded while language settings are misaligned, the Text Library lacks entries for non-English languages, rendering the jump buttons non-functional. The resolution requires copying Text Library entries across all language columns or performing a clean OS project directory download.

Mechanics of APL Faceplate Interlock Navigation (#Jump Tags)

In the SIMATIC PCS 7 Advanced Process Library, technological faceplates (such as MotL and VlvL) provide seamless graphical navigation to interlock logic:
1. The Interlock Connection: In CFC, an interlock output (e.g., Intlk08.Out) is wired to MotL.Permit, Intlk, or Protect.
2. Tag Generation: During OS Compilation, the compiler inspects block connections with valid signal status (ST != 16#FF) and creates an internal WinCC tag formatted as:
@<HID><CFC_Name>/<Block_Name>.Interlock#Jump
3. The Text Library Pointer: The value of this tag is an integer identifier pointing to a text entry in the WinCC Text Library. That text entry contains the exact target picture and block name of the connected interlock.
4. Runtime Jump: When an operator clicks the interlock button, the faceplate script queries the Text Library using the integer ID, opens the interlock faceplate, and highlights the active tripping condition.

Why Jump Buttons Work on ES but Fail on Dedicated OS Stations

Engineers frequently observe that interlock buttons operate cleanly when launching runtime on the Engineering Station, but become disabled as soon as the project is downloaded to dedicated Single Stations or OS Servers:
* Local Project Directory Fragmentation: When an OS project is repeatedly downloaded from the ES to a target station without deleting temporary runtime cache files, obsolete internal tag lists linger in the target database.
* Corrupted OS Project Descriptor: If an OS download fails midway, or if the target path was modified, the client reads a mismatched package descriptor, disabling navigation scripts.
* The Resolution: Deleting the local project directory on the physical OS station and executing a clean, fresh download from the ES re-establishes pristine database synchronization.

The WinCC Text Library Multi-Language Synchronization Gap

A secondary, highly prevalent root cause involves runtime language configuration:
- Language-Specific Text Columns: The WinCC Text Library maintains separate text columns for every configured language (e.g., German, English, Spanish, French).
- The Empty Column Trap: Under specific compilation circumstances, the OS Compiler populates the tag reference strings strictly into the primary engineering language column (e.g., English), leaving the secondary columns completely empty.
- The Symptom: If the OS station's default runtime language is set to German (or if the Windows regional locale differs from the ES), the faceplate script queries the German column, receives an empty string, and automatically grays out the button.

Method: Step-by-Step Resolution and Text Library Alignment

Follow this standardized procedure to restore interlock faceplate buttons across all operator stations:

Step 1: Verify Interlock Connection Prerequisites in CFC

Open the CFC chart: ensure the connected interlock block (Intlk02, Intlk04, Intlk08) is an authentic APL block with S7_m_c := 'true'.
(Note: Connecting basic logic gates like Or04 or And04 will NOT generate jump buttons because basic gates lack faceplate typicals).
Confirm that the interlock signal status is healthy (ST != 16#FF).

Step 2: Inspect and Align the WinCC Text Library

In SIMATIC Manager, open the OS project in WinCC Explorer.
In the navigation tree, open Text Library.
In the Text Library search bar, filter for: Interlock.
Locate the entries corresponding to your technological blocks:
- Observe the text value (e.g., Plant1/UnitA/Chart1/Intlk08).
- Check all language columns (English, German, French):
- If the English column is populated but German/other columns are blank, the button will be disabled whenever running under that language!
Select the populated English text, copy it, and paste it across all blank language columns for that text ID.
Save and close the Text Library.

Step 3: Perform a Clean Download to the Target OS Station

If the Text Library is populated but the physical OS station still shows disabled buttons:
1. Deactivate WinCC Runtime on the physical OS station and close WinCC Explorer.
2. Open Windows File Explorer on the physical OS station:
- Navigate to the project storage directory.
- Delete the entire local project folder (or move it to an archive backup directory).
3. On the Engineering Station (ES), open SIMATIC Manager.
4. Right-click the OS project and select PLC -> Download:
- Confirm target path and computer name.
- Select Entire Scope.
- STEP 7 copies a pristine, uncorrupted project database to the OS station.
5. Launch WinCC Runtime on the OS station.

Verification

To verify that the interlock jump buttons are fully restored:
- Open the motor or valve faceplate on the OS station in WinCC Runtime.
- Verify that the interlock status icons (Permit, Interlock, Protection) display active blue or yellow borders, and the navigation button is enabled (solid, clickable border).
- Click the interlock button: verify that the target Intlk08 faceplate opens instantly as an anchored popup.
- Switch the WinCC runtime language from English to German (or other installed languages): verify that the jump button remains fully active and operational across all languages.

Limitations and Operational Precautions

Basic Logic Gate Interconnections: If an interlock is driven by raw boolean logic (e.g., an AND block output wired directly to MotL.Intlock), PCS 7 cannot create a jump button. Always route logic through an authorized APL interlock block (Intlk02–Intlk08) to enable faceplate navigation.
Subsequent OS Compiles: If you manually populate the Text Library, be aware that running an OS compile with "Entire Scope" may clear manual edits if the regional language settings in SIMATIC Manager are inconsistent. Ensure the default project language is aligned under Options -> Language for Display Devices.
Do Not Delete Projects While Runtime is Active: Never attempt to delete or alter files on the OS station while WinCC Runtime or SQL Server processes are actively accessing database segments.

Engineer FAQ

Can I navigate to an interlock block located in a different CFC chart?

Yes. The APL #Jump mechanism operates globally across the entire S7 program and plant hierarchy. The faceplate script resolves the cross-chart path automatically.

Why does the button work on the ES but fail on the OS?

The ES project database was modified and tested locally, while the OS station was running on an older or partially downloaded project copy with mismatched internal tag IDs.

What happens if the connected interlock block has bad signal status (16#FF)?

If the signal status is 16#FF (Uninitialized / Not connected), the APL faceplate recognizes that no valid technological block is driving the input and automatically disables the button.

How do I verify which internal tag is used for the interlock jump?

In WinCC Explorer, open Tag Management -> Internal Tags. Filter for tags containing .Interlock#Jump. The start value of this tag is the exact Text Library ID number.

Technical References

Siemens Industry Online Support: SIMATIC PCS 7 Advanced Process Library (APL) Manual.
SIOS Entry 109742323: PCS 7 Compendium Part A - Configuration Guidelines (Section: WinCC Text Library and Localization).
SIOS Entry 109809264: SIMATIC Process Control System PCS 7 Advanced Process Library Faceplates.
Siemens Support FAQ: Why Are Interlock Jump Buttons Grayed Out on Faceplates in Multi-Language Projects?

Related Tags

APL
Faceplates
Interlocks
Text Library
WinCC
Navigation
Industrial Automation

Why APL Interlock Faceplate Buttons Are Disabled on WinCC OS and How to Fix Them