Resolving SIMATIC KP300 HMI Text Not Updating After Transfer

Problem Description

The SIMATIC HMI KP300 Basic mono PN (article number 6AV6647-0AH11-3AX0) is a 3.6-inch monochrome basic panel from the Siemens basic-line HMI family, designed for cost-sensitive applications paired with S7-1200 controllers. When a configured project is compiled and transferred from TIA Portal (originally V13, upgraded to V14 SP1) to the KP300, the panel accepts the runtime files, but text elements on screens continue to display the placeholder string "Text" instead of the configured strings. Modified text properties (e.g., changing a label from "1.45" to "1.50") remain locked to the prior value, and new text fields added to a screen render the literal word Text.

The issue persists even after a factory reset and operating-system update of the panel. File-system activity during transfer is visible, which rules out a communication or download failure: the project reaches the device and unpacks successfully. The defect is therefore logic-side and originates in the TIA Portal project configuration rather than in the network path or the panel hardware.

The affected configuration observed in the field was:

• HMI: KP300 Basic mono PN, firmware/Image 11.0.0 (later upgraded to Image 12.0.0.0 via ProSave)
• Controller: SIMATIC S7-1200 (CPU 12xx series)
• Engineering: TIA Portal V13 SP1 (original project), upgraded to TIA Portal V14 SP1
• Symptoms: Text fields show "Text" placeholder; modified label values do not refresh after transfer; new labels are blank

Root Cause Analysis

The defect is a runtime language configuration mismatch. TIA Portal projects for Comfort/Basic panels carry a multilingual text list that is exported into the runtime file set under the \IM\ directory. The panel's runtime boots into one specific language as defined in Runtime Settings → Language & Font. If the configured start-up language index has no translated entries, or if the language index is not enabled in the runtime language list, the runtime substitutes the design-time placeholder token for every unresolvable string.

The original project was developed with multiple languages configured but with index 0 (the default language) either not activated in Runtime Settings → Language & Font, or with a secondary language set as the boot language. Every screen element on the new transfer requested language index 0 strings that did not exist on the panel, so the runtime fell back to Text.

Secondary contributing factors observed in the field:

1. Stale Image files from the older Image 11.0.0 remained in the panel's flash file system after the V13 → V14 SP1 upgrade, causing partial inconsistencies during text-list load.
2. IM folder caching within the TIA Portal project tree held outdated compiled text-list objects that overrode the runtime-side regeneration.
3. Incomplete recompilation after the language fix, meaning the panel received a transfer image whose text tables did not yet reflect the corrected language list.

Affected Versions and Devices

The same root-cause pattern has been reported on related basic-line panels (KTP400 Basic mono PN, KTP600 Basic mono PN, KTP1000 Basic mono PN) when projects migrated across major TIA Portal versions are transferred without a clean rebuild. The behavior is independent of the S7-1200 firmware, which only acts as the I/O data source for the HMI.

Diagnostic Steps

Before applying any corrective procedure, isolate the language configuration as the defect locus using the following checks. Each step is non-destructive.

1. Inspect the project's language list. Open TIA Portal, select the HMI device, navigate to Project tree → Languages & Resources → Project languages. Confirm which language is configured as the editing language and which languages are present in the project text list.
2. Inspect the runtime language table. Select the HMI device, open Runtime Settings → Language & Font. Verify that the language currently used as the design reference (typically index 0) is enabled and that the language set selected at start-up matches the desired operating language.
3. Check the active language at panel boot. Power-cycle the KP300 and observe the language indicator at startup. If the panel boots into a language that has not been translated, the runtime will display Text for every missing entry.
4. Verify text-list entries. Open Project tree → Languages & Resources → Text lists. Confirm that each list has at least one entry per language index. Empty language cells reproduce the Text fallback.
5. Compare on-screen behavior to the simulator. Use the TIA Portal HMI simulation runtime (Start → Simulation → Start with debugger or directly via the toolbar) and compare its text rendering to the live panel. Identical output on both confirms the project, not the panel, as the source.
6. Capture transfer logs. In TIA Portal, enable the extended transfer log (Online → HMI device maintenance → Transfer log) and inspect the .log file for any WString or text-pool warnings during compile.

Solution: Language Configuration and Clean Rebuild

The complete remedy combines a runtime-language correction, an OS upgrade of the panel, deletion of the project's stale IM cache, and a full recompile. The steps below restore correct text rendering.

Step 1 – Configure Runtime Languages

1. In TIA Portal, select the HMI device in the project tree.
2. Open Runtime Settings → Language & Font.
3. Enable the language(s) the project is actually translated into. If only one language is needed, enable only that language and deactivate all others to prevent boot into an empty language slot.
4. Set the desired language as the active language (the entry flagged as the start-up language).
5. Click OK to apply.

If multiple languages are needed, the user must be able to switch languages at runtime. Plan for the SetLanguage system function described in Step 5.

Step 2 – Update the Panel Operating System

Use Siemens ProSave to update the panel image to Image 12.0.0.0 (or the latest released image for the KP300 Basic mono PN). The KP300 ships with multiple OS images; using the latest published image eliminates stale text-pool caches in the panel's flash file system.

1. Launch ProSave (installed with TIA Portal under Start → Siemens Automation → ProSave).
2. Select Device type → KTP300 Basic mono PN.
3. Select Connection → Ethernet and enter the panel IP address.
4. Click Operating System Update, browse to the HMI Image file (*.img) provided with TIA Portal V14 SP1 under Installation path \Support\Images\HMI\KTP300_Basic.
5. Confirm the update. The panel will reboot; this operation does not erase the IP address or the project, but it does regenerate internal text-pool indices.

Step 3 – Remove the IM Folder and Rebuild

The IM folder inside the TIA Portal project directory holds compiled intermediate images that TIA Portal reuses for incremental compiles. After major TIA Portal upgrades, these intermediates can lag the source language configuration and produce corrupted text tables at transfer time.

1. Close TIA Portal completely.
2. In the Windows file system, navigate to the project folder (default: %USERPROFILE%\Documents\Automation\Projects\<ProjectName>\).
3. Delete the IM subdirectory. This subfolder is regenerated on the next full compile.
4. Reopen the project in TIA Portal.
5. Right-click the HMI device and choose Compile → Software (rebuild all).

Step 4 – Re-Transfer the Project

1. Confirm the panel is in transfer mode (or autotransfer is enabled in the panel control panel).
2. Select the HMI device in TIA Portal and choose Online → Download to device → Software (complete).
3. Choose Replace all objects in the target device to overwrite the runtime text pools completely.
4. Wait for the panel to reboot and load the new runtime.
5. Verify that the previously empty fields now show the configured strings.

Step 5 – Enable Runtime Language Switching (if required)

For projects requiring two or more languages, configure a button or key event with the system function SetLanguage. The function takes an integer argument corresponding to the language index.

// Example: SetLanguage usage on a Button Click event
// In TIA Portal: Button → Events → Click → Add function → SetLanguage
// Language index mapping (verify against your project):
//   0 = Language 1 (default)
//   1 = Language 2
//   2 = Language 3
SetLanguage(0);   // Switch to default language on button press
SetLanguage(1);   // Switch to secondary language on button press

The full function reference for SetLanguage is documented in the TIA Portal Help under System functions → SetLanguage and in the WinCC Comfort/Manual V14 SP1 reference manual.

Verification

After applying the corrective procedure, perform the following verification checks to confirm full recovery:

1. Static text check: Inspect every screen on the live panel and confirm that previously modified labels (e.g., "1.50") render the new value, and that newly added labels render their configured strings rather than Text.
2. Runtime language cycling: Trigger the SetLanguage function (if implemented) and verify that switching between language indices updates every screen text without restart.
3. Transfer log review: Inspect the TIA Portal transfer log for any remaining WString conversion warnings or text-pool errors.
4. Image version confirmation: On the panel, navigate to Control Panel → System → Image Version and verify it reads 12.0.0.0 (or the target image).
5. Reboot consistency: Power-cycle the panel twice in succession; text must render correctly on every boot without manual intervention.

Related Runtime Settings to Audit

When the language configuration has been corrected, audit the following runtime settings to prevent recurrence:

Best Practices to Prevent Recurrence

1. Pin a single image version per project. Lock the HMI Image version in TIA Portal under HMI device → Device Version. Avoid mixing Image 11.x and 12.x projects across an installed base.
2. Clean the IM folder after every major TIA Portal upgrade. Treat the V13 → V14 SP1 transition as a hard boundary; always delete the IM folder and rebuild.
3. Use ProSave for OS updates, not the panel's own recovery mode. ProSave preserves the IP address and produces a verified, signed image load.
4. Maintain a single source of truth for language indices. Document the language index → language mapping in the project README and reference it from any SetLanguage call sites.
5. Run the simulator against every transfer. Before pushing to the live panel, run the TIA Portal HMI simulator and verify that the simulator displays the same text rendering expected from the panel. Discrepancies expose project-side language issues early.
6. Avoid partial downloads for language changes. When text-list entries change, always perform Software (complete) rather than Software (incremental) to force regeneration of the runtime text pools.
7. Audit multilingual entries before each transfer. Open Languages & Resources → Text lists and use the Check consistency function to flag untranslated strings.

Troubleshooting Matrix

Documentation References

• SIMATIC HMI KP300 Basic mono PN Operating Instructions
• SIMATIC WinCC Engineering V14 SP1 Manual
• SIMATIC ProSave V14 SP1 Service Tool Manual
• SIMATIC S7-1200 Programmable Controller System Manual
• KP300 Basic mono PN Product Support Page

FAQ