Resolving KTP400 Basic Panel Stuck on Transfer Screen at Startup

Problem Summary

The 2nd-generation Siemens SIMATIC KTP400 Basic (and related Basic Panels such as KTP700 Basic, KTP900 Basic, KTP1200 Basic) occasionally returns to the loader screen — Transfer / Start / Settings — immediately after power-up or on every restart. The runtime project no longer launches, the Start button is visible but greyed out, and pressing it does not initiate the HMI application. The PLC is unaffected: tags continue to update, pings to the panel succeed, and the loader responds to remote commands such as Flash LED from TIA Portal. Field reports show the failure can appear 4–5 months after commissioning without any change to the project, firmware, or wiring, and affects multiple panels at the same site.

Affected Hardware and Firmware Range

The behavior is reproducible across the 2nd-generation Basic Panel family (KTP400 Basic mono and color variants share the same loader behavior). Field failures correlate with the factory-shipped firmware image shipped with panels delivered before the firmware revision that introduced loader stability fixes. Updating the image via a TIA Portal transfer resolves the failure in the majority of cases.

Root Cause Analysis

Two distinct root causes can produce this symptom set:

1. Loader firmware bug (primary): Early 2nd-generation Basic Panel firmware images contain a defect in the loader's project integrity check. After a number of write cycles to internal flash or after prolonged operation, the loader misinterprets the runtime project's signature as invalid and forces the panel into recovery mode at every boot. The runtime is not actually corrupted — the loader simply refuses to execute it. The Start button is rendered in a greyed state because the loader cannot start the (correctly stored) image.
2. Aborted transfer via the data record area pointer (secondary): When the HMI receives a data record transfer from the PLC, the data mailbox status Transfer completed with error is set if the transfer is aborted. If the runtime project subsequently depends on configuration data that was never fully written, the loader can flag the project as invalid on the next boot. Documented trigger conditions include a disconnected Ethernet cable during transfer, PLC stop during transfer, and insufficient free memory on the panel. See the official TIA Portal documentation on Possible causes of error when transferring data records for the full trigger list.

The reason the panel still responds to Flash LED and ICMP echo is that the loader — not the corrupted runtime — owns the network stack and the panel service channel at boot. The same network reachability that lets you ping the panel is what makes firmware recovery over Ethernet possible.

Prerequisites

• TIA Portal V13 SP2 or later (V13 SP1 exhibits known loader-related transfer issues with 2nd-generation Basic Panels and must be updated first).
• Ethernet connectivity between the PG/PC and the panel on the same subnet. The panel must respond to ping <panel-IP>.
• Access to the original TIA Portal project file (.ap13) that matches the panel, or an export of the HMI configuration.
• For the destructive recovery path (USB image): Siemens support registration to obtain the Basic2nd_Recovery_System.zip image from Entry ID 109744950 — note that this entry is export-restricted and may require several days for download authorization.
• Administrator rights on the PG/PC to modify the Set PG/PC Interface settings.

Resolution Path — Primary: TIA Portal Transfer with Firmware Update

This is the recommended path. It restores the loader image, the runtime image, and the project in a single operation.

Step 1 — Upgrade the Engineering Software

1. Uninstall any TIA Portal V13 SP1 components.
2. Install TIA Portal V13 SP2 (or the highest SP supported by your license). V13 SP2 contains updated panel image components and corrected transfer behavior for 2nd-generation Basic Panels.
3. Open the original project and confirm it compiles without errors. If you do not have the original project, use Project > Retrieve from the TIA Portal backup.

Step 2 — Correct the PG/PC Interface Assignment

An incorrect access path is the single most common reason a transfer starts but fails silently. Configure the interface as follows:

1. Open Windows Control Panel → Set PG/PC Interface.
2. In the Access Path tab, locate Access Point of the Application and select S7ONLINE (STEP 7) -> TCP/IP.
3. In Interface Parameter Assignment Used, select the Ethernet adapter that ends with ... TCPIP.1. Do not select the ... TCPIP.Auto.1 variant — it picks an adapter heuristically and is unreliable for panel transfers.
4. Click OK to apply. Restart TIA Portal so the new access point is bound.

Step 3 — Verify the Panel Transfer Settings

1. Power-cycle the panel.
2. On the loader screen, tap Settings → Transfer Settings.
3. Set the channel to Ethernet.
4. Set the mode to Automatic (the loader will accept a remote transfer without requiring a tap on the panel).
5. Confirm the panel's IP address, subnet mask, and gateway match the project configuration.
6. Return to the loader.

Step 4 — Transfer the Project and Firmware

1. In TIA Portal, select the HMI device in the project tree.
2. Choose Online > HMI Device Maintenance > Firmware Update or simply Download to Device > Software (all).
3. When prompted, select the panel as the target (it should appear in the accessible nodes list via Flash LED).
4. TIA Portal will first push the updated loader/runtime image, then the compiled HMI project. Do not power off the panel during this operation; a typical 400-type panel takes 4–8 minutes for the full image plus project.
5. Wait for the green Transfer completed successfully dialog before pressing OK.

Step 5 — Reboot and Validate

1. Power-cycle the panel.
2. Confirm the runtime project launches directly without displaying the loader.
3. If the loader still appears, repeat Step 4 — the first transfer updates the loader, the second writes the runtime image reliably on top.

Resolution Path — Secondary: Reset to Factory Settings via Loader

If the TIA Portal transfer fails repeatedly (loader reports Download interrupted or transfer completes in < 1 second):

1. Power off the panel.
2. Hold the touch area at the upper-right corner of the screen.
3. Apply power while holding the touch contact for ~10 seconds.
4. The panel enters the Service / Recovery menu.
5. Select Reset to Factory Settings. The panel will reboot into a clean loader state.
6. Retry Step 4 of the primary resolution path.

Resolution Path — Tertiary: USB Recovery Image

Use only when both the Ethernet transfer and the loader reset fail. This rewrites the full panel firmware from a USB stick.

1. Request the export-restricted image from Siemens Entry ID 109744950 (USB Recovery image for 2nd-generation Basic Panels). Note Siemens states that the download authorization review may take several days.
2. Unzip the archive and copy the image files to a FAT32-formatted USB stick.
3. Insert the USB stick into the panel's USB port.
4. Power off the panel, then power on while holding the upper-right touch area.
5. Follow the on-screen prompts to select the USB source and confirm the recovery write.
6. When recovery completes, remove the USB stick and reboot into the loader.
7. Re-apply TIA Portal V13 SP2 transfer as in the primary path.

Prosave / SIMATIC Prosafe Tool Notes

Siemens ProSave (formerly known as Prosafe) is a service tool shipped with TIA Portal that performs backup, restore, and firmware update over Ethernet independent of the TIA Portal project compiler. If the full TIA Portal download fails:

1. Launch ProSave from C:\Program Files\Siemens\Automation\TIA Portal V13 SP2\bin.
2. Device type: KTP400 Basic color PN (or matching article).
3. Connection: Ethernet, IP address = panel IP.
4. Operation: Update Operating System, then Restore with a backup created earlier.

ProSave isolates the loader update from the project compile and frequently succeeds where the TIA Portal integrated transfer aborts.

Verification Checklist

Troubleshooting Matrix

Prevention

• Maintain a baseline TIA Portal project archive for every machine. Store the .ap13 file in version control alongside the PLC project.
• Use ProSave to create a panel backup immediately after commissioning and store it in the same archive. A ProSave backup restores in minutes and avoids the export-restricted image path entirely.
• Standardize on TIA Portal V13 SP2 or later for any work involving 2nd-generation Basic Panels.
• When using the data record area pointer, ensure the PLC remains in RUN and the Ethernet cable is stable for the entire transfer. The TIA Portal documentation lists these as primary abort triggers that can leave the project in a non-executable state.
• Verify the loader version in Settings > System Information during commissioning and record it in the machine documentation.

Key Constants and Parameters

FAQ