Resolving Process Object View Grid Malfunctions in Parameters and Signals Tabs

The malfunction in SIMATIC PCS 7 Process Object View (POV) where the Signals tab incorrectly displays parameters instead of I/O signals occurs when the serialized grid view state in the Windows User Registry becomes corrupted or when operating under an uncertified Windows 10 build (such as Windows 10 Enterprise 2016 LTSB on baseline PCS 7 V9.0). To resolve this, close SIMATIC Manager and delete the corrupted registry layout key under HKEY_CURRENT_USER\Software\Siemens\STEP 7\2.0\Applications\s7thapax, reset POV view filters to Standard, and install SIMATIC PCS 7 V9.0 Service Pack 1 to ensure full table compatibility.

Process Object View Architecture and Registry View State Caching

In SIMATIC PCS 7, the Process Object View (POV) (s7thapax.exe) provides a multi-tab engineering spreadsheet allowing bulk manipulation of automation assets. Each tab (General, Blocks, Parameters, Signals, Messages, Picture Objects, Archive Tags) queries specific database schemas inside the STEP 7 project.

To provide a consistent user experience, POV serializes user interface customizations—such as adjusted column widths, column visibility, custom sorting, and active filter criteria—into the Windows Registry under the current user's profile (HKEY_CURRENT_USER). On every application launch, POV reconstructs its GUI grid according to these cached binary registry keys.

Root Causes: Registry View Corruption and Windows 10 Build Incompatibility

Two compounding issues trigger the corruption where the Signals tab displays the Parameters schema:

Corrupted Registry Grid Serialization: When SIMATIC Manager terminates abnormally (system crash, forced Task Manager end-task, or power dip), the binary serialization stream written by s7thapax.exe is truncated. The column pointer array for the Signals tab becomes misaligned, causing the grid controller to map the cached schema of Tab 3 (Parameters) onto Tab 4 (Signals). Because this is stored in the user profile, the defect persists across all projects.
Unreleased Windows 10 Editions: Baseline SIMATIC PCS 7 V9.0 was certified exclusively for Windows 10 Enterprise 2015 LTSB. Running baseline V9.0 on Windows 10 Enterprise 2016 LTSB or newer SAC builds induces Microsoft Common Controls (comctl32.dll) rendering bugs. Siemens formally resolved these grid control defects in PCS 7 V9.0 SP1.

Diagnostic Matrix for Process Object View Grid Failures

The table below details symptoms, root causes, and corrective actions for Process Object View grid malfunctions:

Symptom / BehaviorUnderlying Root CauseRegistry / System ComponentCorrective Engineering ActionSignals tab shows ParametersDesynchronized column cache in user profile.HKCU\...\Applications\s7thapaxDelete registry key; restart SIMATIC Manager.Defect persists across all projectsUser-profile scope (independent of project DB).Windows Current User RegistryClear registry settings; affects all projects.Windows 10 2016 LTSB InstabilityUnreleased OS environment for baseline V9.0.OS Kernel / Common ControlsUpgrade software to SIMATIC PCS 7 V9.0 SP1.Disappearing ColumnsCorrupted column width setting ($0\text{ pixels}$).Grid Column Width CacheExecute View -> Filter -> Standard / Reset.Empty Grid / Blank RowsActive filter masking all records.Filter Criteria DialogSelect View -> Filter -> Clear Filter.

Step-by-Step Procedure to Clear POV Registry Cache and Restore Tabs

Close All Siemens Engineering Applications:
- Save your work and exit SIMATIC Manager, CFC, and WinCC Explorer.
- Open Windows Task Manager: ensure processes s7tgtopx.exe and s7thapax.exe are completely terminated.
Delete Corrupted POV Registry Settings:
- Open the Windows Registry Editor (regedit.exe) as the active user.
- Navigate to the following path:
text HKEY_CURRENT_USER\Software\Siemens\STEP 7\2.0\Applications\s7thapax
- Right-click the key s7thapax (or its sub-keys Settings / View) and select Delete.
- Note: Deleting this key does not alter project engineering data; it simply clears cached column layout preferences.
Relaunch SIMATIC Manager and Reset Filters:
- Open SIMATIC Manager and open your multiproject.
- Open Process Object View: select View -> Filter... -> click Standard (Reset Defaults).
- Select the Signals tab: confirm that the grid cleanly populates with peripheral addresses, signal names, and I/O directions.
Upgrade to PCS 7 V9.0 SP1 (Preventative Action):
- If operating on Windows 10 Enterprise 2016 LTSB, install SIMATIC PCS 7 V9.0 Service Pack 1 to ensure full OS qualification and prevent grid serialization re-corruption.

Verification

Verify POV functionality through the following checks:
1. Click the Parameters tab: verify that block inputs/outputs and numerical values display accurately.
2. Click the Signals tab: confirm that the table header displays signal-specific columns (Signal, Chart, Block, I/O, Address, Data Type).
3. Open multiple distinct projects: verify that the Signals tab remains correctly formatted without reverting to parameter schemas.

Limitations and Operational Precautions

Exercise caution when editing the Windows Registry. Always export a backup of the HKEY_CURRENT_USER\Software\Siemens branch before modifying keys. Furthermore, avoid utilizing registry cleaner utilities or running automated profile virtualization software that arbitrarily deletes or rewrites Siemens application keys during user logoff.