Customizing Event Text on ExternalMsg Inputs of APL Technological Blocks in SIMATIC PCS 7

In SIMATIC PCS 7, customizing the event text for external message inputs (ExtMsg1, ExtMsg2, ExtMsg3) on APL blocks like MotL (FB1850) requires modifying message signals SIG4, SIG5, and SIG6 in the block's Message Configuration dialog and ensuring visual language alignment. If updated event texts fail to appear on the WinCC OS after compilation, the root cause is almost always a language mismatch between SIMATIC Manager's 'Language for Display Units' and the WinCC OS Text Library language. When text is edited while SIMATIC Manager is set to an alternate language (e.g. Portuguese), the English column remains unpopulated; AS-OS compilation then transfers default English text ('External message 1'). Harmonizing display languages resolves the issue.

Message Architecture of ExternalMsg Inputs on APL Blocks

In SIMATIC PCS 7 Advanced Process Library (APL), technological blocks such as MotL (FB1850) incorporate integrated Alarm_8P function block calls to generate operator messages directly from the automation controller. Within the block's internal message structure, specific signal channels are pre-assigned to external inputs:

Block Input ParameterAlarm_8P Signal IdentifierDefault Event Text TemplateTypical Engineering ApplicationExtMsg1SIG4$$BlockComment$$ External message 1Primary process trip / interlock faultExtMsg2SIG5$$BlockComment$$ External message 2Auxiliary equipment fault / drive warningExtMsg3SIG6$$BlockComment$$ External message 3Local isolator open / maintenance switch trip

The token $$BlockComment$$ is an automated macro replaced during OS compilation with the technological block's configured comment. Engineers can overwrite or append text to create descriptive messages, such as $$BlockComment$$ High Bearing Temp Trip.

Instance-Level vs Project-Wide Message Customization

Depending on engineering requirements, message texts can be modified at two distinct levels:

Instance-Specific Customization (Single Motor):
- In the specific CFC chart, right-click the MotL block and select Object Properties.
- Click Messages.... Modify the text for SIG4, SIG5, or SIG6.
- This modification applies exclusively to that individual motor instance.
Project-Wide Template Customization (Master Data Library):
- Open the Master Data Library block folder.
- Locate FB1850 (MotL). Right-click and select Special Object Properties -> Message....
- Adapt the default text templates for SIG4..SIG6.
- Propagate changes across the multiproject using Options -> Charts -> Update Block Types....

Language for Display Units and WinCC Text Library Synchronization

The most persistent issue encountered when customizing external message texts is that changes appear correct in CFC, yet the WinCC OS Runtime stubbornly displays the default string External message 1. This occurs due to multi-language database segregation:

SIMATIC Manager stores project texts in a multi-column database where each language (English, German, French, Spanish, Portuguese) maintains a separate text string.
If an engineer's SIMATIC Manager interface or editing language is set to Portuguese (Brazil), typing new event text writes only to the Portuguese database column.
If the WinCC OS project runtime language is set to English (United States), the AS-OS Engineering compilation utility reads exclusively from the English column.
Because the English column was never modified, AS-OS Engineering transfers the factory-default English string.

To resolve this, open SIMATIC Manager and select Options -> Manage Multilingual Texts -> Language for Display Units. Set the default display language to match the WinCC OS Runtime language (e.g., English US), enter the desired message text, and recompile the OS.

Verification

Verify that the customized external message text propagates into WinCC through these diagnostic checks:

WinCC Text Library Audit: Open WinCC Explorer on the OS Server. Open Text Library. Filter by the motor block tag name. Confirm that the customized text appears under the active runtime language column.
Simulate External Message Trip: In CFC Test Mode, force ExtMsg1 = 1 on the target motor block.
WinCC AlarmControl Banner Display: Observe the incoming message on the OS alarm line. Verify that it displays your exact custom text (e.g. High Bearing Temp Trip) instead of External message 1.

Limitations and Operational Precautions

When editing message texts across multi-station projects, adhere to these safeguards:

Language Consistency Across Multiproject: In distributed engineering environments, ensure all participating Engineering Stations utilize the same default language for display units to prevent language column divergence.
Avoid Deleting $$BlockComment$$: Unless project standards strictly dictate otherwise, retain the $$BlockComment$$ token; deleting it removes the equipment description from the alarm text, making operator identification difficult.
OS Compile Scope: When modifying message texts, select Compile OS -> Changes Only. If text updates fail to refresh in the WinCC Text Library, perform an Entire OS compilation with 'Tags and messages' selected.

Engineer FAQ

Why did OS compile not update the message text even though I saved CFC?

The text was likely entered under a different language column in SIMATIC Manager than the active language configured in WinCC. Synchronizing the 'Language for Display Units' before editing resolves the mismatch.

Can I export all message texts to Excel to translate them in bulk?

Yes. In SIMATIC Manager, select Options -> Manage Multilingual Texts -> Export. Export the text table to a CSV file, edit the language columns in Excel, and re-import via Manage Multilingual Texts -> Import.