Troubleshooting Siemens TP2200 HMI Freeze: Root Cause, Diagnostics, and IM Folder Recovery

Recurring grey-screen freezes on a Siemens SIMATIC TP2200 Comfort Panel running TIA Portal V15.1.0.6 firmware, even after hardware replacement, are almost always caused by a corrupted runtime image, exhausted WinCE resources, or a Profinet-side fault that the panel cannot recover from gracefully. This reference walks through the full diagnostic path, the official IM folder deletion recovery procedure, and the supporting checks for power quality, EMC, and Profinet cable integrity that prevent the freeze from returning on a 2-week cadence.

1. Problem Definition and Symptoms

The grey screen state is the Comfort Panel's default fallback when the HmiRuntime.exe process is no longer responsive. Unlike a blue diagnostic screen, the panel cannot even surface a status dialog, which means the fault occurred before or during runtime initialization, or the watchdog timer has fired without recovery.

2. Windows CE 7 Event Logging on Comfort Panels

Unlike Windows 10 IoT or Windows Server, Windows Embedded Compact 7 does not include the desktop Event Viewer (eventvwr.msc). Diagnostic information is instead stored in compressed binary logs and circular buffers in the panel's flash file system.

2.1 Where the Logs Live

• \Flash\System\SystemLog.txt — system-level events, startup, and shutdown
• \Flash\Log\AlarmLog.txt — alarm logging buffer when configured
• \Flash\Log\TagLogging\*.csv — historical tag data, file-size controlled
• \Flash\System\Backup\*.log — recent configuration/restore events
• \System\EventLog\ — compact binary events readable only by Remote Diagnostics

2.2 How to Read the Logs

1. Open the Control Panel on the panel: Start > Settings > Control Panel (or use the small Start arrow on the taskbar).
2. Launch WinCC Explorer > Tools > Diagnostic in online mode — only available on the engineering station.
3. From the engineering PC, use TIA Portal > Online > HMI Diagnostics while connected via Profinet/Ethernet.
4. For deep forensics, deploy SIMATIC ProSave to back up the entire flash image, including logs, to the PC.

Reference: Siemens KB 109746419 — Diagnostic options for Comfort Panels and the SIMATIC HMI Operator Panel Manual Collection.

3. Root Cause Analysis: Why the TP2200 Freezes

From the engineering discussion, the most likely root cause is a corrupted or partially compiled runtime image in the IM folder, with secondary contributors from Profinet/EMC conditions. The analysis below ranks causes by probability for a 2-week recurring freeze.

3.1 Corrupt or Out-of-Date IM Folder (Primary Cause)

The IM folder is generated during TIA Portal's incremental compilation. It contains the intermediate representation of screens, tags, alarms, and recipes translated for the Comfort Runtime. When the TIA Portal V15.1.0.6 compile chain produces a malformed IM entry, the runtime on the panel can:

• Loop indefinitely during startup, triggering the watchdog
• Allocate fragmented memory and crash after N navigation cycles
• Load a screen with broken tag references and abort the runtime

Siemens' official remedy, confirmed by Siemens support in the source thread, is to delete the IM folder, then perform a full recompile of both the HMI software and the HMI hardware, then download the rebuilt project. See the official procedure: Siemens KB 109751264 — Deleting the IM folder in TIA Portal.

3.2 Function-Scope Exceeded (Secondary Cause)

Each Comfort Panel has a maximum function scope defined by the licensed options and the panel's flash/RAM. When the compiled project exceeds the scope (number of tags, screens, alarms, archives, scripts), the runtime may degrade to a frozen grey screen rather than refusing to start. The official scope table is published in: Siemens KB 109751320 — Scope of functions for WinCC Comfort/Advanced.

3.3 WinCE Resource Exhaustion (Memory Leak)

A recurring 14-day cycle strongly suggests a memory leak that accumulates until the working set is exhausted. Common offenders:

• Cyclically scheduled VB scripts with non-disposed COM objects
• User-defined functions that instantiate tags without proper scope release
• Log file rollover hitting flash wear thresholds
• Recipe views opening persistent DB connections that are not closed on screen change

3.4 Profinet Fault Cascade

A Profinet IO device going offline (for example, a motor disconnector opening and dropping an ET200SP station) can flood the panel with diagnostic interrupts. If the panel is configured as a Profinet IO Controller and a subordinate device transitions to Station failure with high-priority diagnostics enabled, the runtime can be overwhelmed. Review the panel's Profinet diagnostics buffer in TIA Portal: Online > Diagnostics > Profinet Diagnostics.

3.5 Power Supply and EMC (Environmental Cause)

A 24 VDC supply that dips below 19 V during contactor or motor starter operation will reset the panel or trigger a brownout detector. The TP2200 has a built-in diagnostic buffer that records under-voltage events. Verify with a clamp-on DC ammeter and oscilloscope on the panel's 24 V terminals during a known freeze window.

4. Motor Disconnector and Profinet Impact Analysis

Opening a motor disconnector does not directly freeze the HMI, but it can cause a Profinet device behind that disconnector to go offline, which can trigger the cascade described in §3.4. The chain of events is:

1. Motor disconnect is opened.
2. ET200SP / SINAMICS / SIMOCODE station on that disconnect loses 24 V or 400 V supply.
3. Profinet IO Controller (CPU or panel if used as controller) detects station failure.
4. Diagnostic alarm flood is sent to all configured supervisors including the HMI.
5. If the HMI has high-priority diagnostic events enabled with a tight CPU scheduler, the runtime thread starvation leads to a grey screen.

5. Solution: IM Folder Deletion and Full Recompilation

This is the Siemens-endorsed primary fix for recurring Comfort Panel grey-screen freezes that survive a hardware swap.

5.1 Prerequisites

• TIA Portal installed on engineering PC (V15.1 minimum, ideally the latest update)
• Latest SIMATIC HMI TP2200 Comfort image — upgrade to the latest service pack before recompiling. The latest image at time of writing is V17 / V18; available from: Siemens KB 109751264
• Ethernet connection from PC to panel (or via PN/PN coupler)
• Project archive (.zap) backup of the current state

5.2 Step-by-Step Procedure

1. Archive the project: In TIA Portal, Project > Archive. Store the .zap file in a versioned location with a date stamp.
2. Close TIA Portal completely. This is mandatory — the IM folder cannot be deleted while the project is open.
3. Locate the project folder on disk. The default TIA Portal project path is C:\Users\<User>\Documents\Automation\<ProjectName>\.
4. Delete the IM folder inside the project directory. This is a sibling of the System, IM_data, and Logs folders. Windows may show a permission prompt; confirm deletion.
5. Reopen the project in TIA Portal. The portal will mark HMI and PLC software as inconsistent (yellow icon).
6. Recompile HMI software: Right-click the HMI device > Compile > Software (rebuild all). This forces a complete regeneration of all IM content.
7. Recompile HMI hardware: Right-click the HMI device > Compile > Hardware (rebuild all). The hardware compilation regenerates the device description and Profinet parameters.
8. Recompile PLC software if the PLC has cross-references to the HMI tags. Right-click the PLC > Compile > Software (rebuild all).
9. Download to the HMI: Select the HMI > Online > Download to device. Use Overwrite all in the download dialog. Wait for the Transfer completed successfully message.
10. Download to the PLC with the matching rebuilt software.
11. Restart the panel: Use Start > Restart or a controlled power cycle.
12. Monitor the panel for at least 30 days, recording any freeze event with timestamp.

6. Firmware and Image Update Procedure

If the IM folder fix does not resolve the freeze, escalate to a firmware/image update. TIA Portal V15.1.0.6 is from 2018 and has known stability fixes in subsequent updates.

1. Download the latest Comfort Panel image from Siemens' SIOS support portal (search: HMI TP2200 Comfort image).
2. Open ProSave (installed with TIA Portal).
3. Select Device type = Panel, Connection = Ethernet, enter the panel IP.
4. Choose Update operating system and select the downloaded .fwf image file.
5. Click Update OS and wait for the panel to reboot with the new image.
6. After the image update, transfer the rebuilt project (from §5) to the panel.

Reference: Siemens KB 109746419 — Performing an OS update for SIMATIC HMI Panels.

7. Power Supply and EMC Verification

If the freeze returns after the IM folder fix and firmware update, the cause is environmental. Verify the 24 VDC supply chain.

7.1 DC Supply Checks

7.2 EMC and Grounding

• Confirm the panel's functional earth (FE) terminal is bonded to the cabinet ground bar with a low-impedance strap (no paint, star washer, < 50 mm braid preferred).
• Verify the 24 V return (M) is bonded to ground at one single point (typically the PSU) to prevent ground loops.
• Use ferrite beads on the 24 V supply and Profinet cables near the panel if high-frequency noise is suspected.
• Ensure the Profinet cable is at least 200 mm from VFD power cables and that the cable shield is bonded 360° at every connector.

8. Profinet Diagnostics and Configuration

Profinet-induced freezes are best diagnosed through the Profinet Diagnostics Buffer on both the PLC and the HMI. Key fields to inspect:

• Station failure events with timestamp correlation to motor disconnector operations
• Port/link down events indicating cable or connector faults
• Device replacement events that may have triggered an unintended runtime reload
• Update time violations showing devices missing their cyclic update window

8.1 Recommended Profinet Settings

Reference: Siemens KB 49948856 — Profinet Diagnostics Configuration and the SIMATIC WinCC Comfort/Advanced manual.

9. Long-Term Preventive Measures

Once the immediate freeze is resolved, implement the following to prevent recurrence.

1. External alarm and tag logging: Configure WinCC alarm logging and tag logging to write to an SMB share on the plant historian. Local flash wear is the leading cause of long-term Comfort Panel degradation.
2. Disable unused runtime services: If you do not use the Sm@rtServer, OPC UA server, or Web server, disable them in the runtime settings. Each consumes baseline RAM.
3. Schedule weekly reboots for panels with high memory pressure. WinCC Comfort supports scheduled Restart tasks via the scheduler.
4. Validate project before each download: Use Project > Compile > Check consistency to catch tag references and screen errors that would otherwise produce a corrupt IM folder.
5. Source-control the TIA project with Git or SVN. TIA Portal supports External source management for blocks; for the full project, archive .zap files with a tag for each release.
6. UPS the 24 V supply with a DC buffer module (e.g., SITOP UPS1600) to ride through brief sag events.
7. Monitor Profinet health with PRONETA (Siemens free tool: siemens.com/proneta) to baseline update times and identify degrading devices before they cause an outage.

10. Verification and Monitoring

After the IM folder procedure and any firmware update, verify the fix with a structured 30-day monitoring plan.

10.1 Verification Checklist

10.2 Escalation Path

If the freeze returns within 30 days, escalate in this order:

1. Capture the last 5 minutes of Profinet diagnostics and the flash system log immediately after the freeze.
2. Open a Siemens Support Request (SR) at SIOS with the panel serial number, project version, and the captured logs.
3. Consider migrating to a TP2200 with a current firmware image (V17 or later) or moving to a Unified Comfort Panel (MTP/MTP2200) if the V15.1.0.6 base image is fundamentally incompatible with the plant Profinet traffic profile.

11. Frequently Asked Questions