Resolving Multi-User Engineering Chart Lockouts and Access Conflicts in SIMATIC PCS 7

Continuous Function Chart (CFC) lockouts occur in SIMATIC PCS 7 multi-user engineering environments when an automation station database retains an exclusive user lock from a previous engineering session. If a chart is left open, edited online, or terminated abnormally on a secondary engineering station, the primary station cannot open or download the chart, displaying an error that the object is in use. Resolving this issue requires terminating lingering remote sessions, releasing locked database records via project reorganization, clearing orphaned network file handles on the central project server, and ensuring current CFC update packages are installed.

Multi-User Engineering Locking Architecture in PCS 7

SIMATIC PCS 7 supports multi-user engineering across a multiproject structure, enabling multiple engineers on distributed Engineering Stations (ES) to work simultaneously on different automation stations (AS) or operator stations (OS). To prevent data corruption, STEP 7 and CFC implement a strict record-locking mechanism:

Object-Level Exclusivity: While multiple engineers can simultaneously access different charts within the same AS, only one engineer can open a specific CFC or SFC chart for editing or online monitoring at any given moment.
Session Tracking: When an engineer opens a CFC chart, the CFC editor registers a lock record in the local database files (s7asr.dbf, s7amx.dbf, or internal lock tables) and creates temporary session locks across the plant engineering network share.
Online Mode Restrictions: When an ES connects online to a controller to test logic or view dynamic values, the chart's write lock is upgraded to prevent concurrent program downloads or conflicting changes from another station.

Root Causes of Persistent Chart Lock Errors

In PCS 7 V9.0 SP3 and related versions, engineers often encounter the error "The chart is already opened by another user or another application" even when the secondary ES has been shut down. This persistent lock state is driven by several failure modes:

Abnormal Network Termination: If a secondary ES loses network connection to the project server while a chart is open online, the server continues to hold SMB file locks because TCP keepalive timeouts have not elapsed.
Crash of s7jcfcax.exe or s7tgtopx.exe: If the CFC editor crashes or is killed via Windows Task Manager, the database unlock sequence is bypassed, leaving the "chart open" flag permanently set in the project database.
Uncompiled Online Changes: If changes were made to an online chart on a secondary station without saving and closing cleanly, the change buffer remains assigned to the secondary station's session ID.
CFC Software Deficiencies: Certain releases of CFC V9.0 SP3 suffered from synchronization defects in multi-user environments where closing a chart did not immediately trigger the lock release across multi-project network shares.

Step-by-Step Procedure to Clear Stuck Chart Locks

Follow these progressive steps to clear dangling chart locks without risking project data integrity:

Step 1: Release Server-Side SMB Handles

On the Central ES or server hosting the shared multiproject, open Windows Computer Management (compmgmt.msc).
Navigate to System Tools -> Shared Folders -> Open Files.
Locate any open files associated with the locked AS subproject path (specifically files under the widoff or global subfolders).
Right-click the locked files and select Close Open File.
Under Shared Folders -> Sessions, right-click any idle sessions from the secondary ES and select Close Session.

Step 2: Clean Local Workstation Cache

On the secondary ES that previously accessed the chart, ensure SIMATIC Manager and all engineering tools are completely closed.
Open Task Manager and ensure no lingering Siemens processes (s7jcfcax.exe, s7tgtopx.exe, s7abapx.exe) remain running.
Restart the secondary ES if processes cannot be terminated cleanly.

Step 3: Clear Temporary Project Lock Markers

On the central project server, browse to the specific AS project folder in Windows Explorer.
Ensure Windows is configured to show hidden and system files.
Check the project directory and subdirectories for temporary files matching *.loc, *.tmp, or *.lck.
If present and all engineering stations have closed SIMATIC Manager, delete these orphaned lock files.

Project Reorganization and Cross-Reference Rebuilding

If the chart remains locked after releasing network handles, the internal database flags must be rebuilt using SIMATIC Manager's reorganization function:

Open SIMATIC Manager on the primary ES.
Ensure no other engineering stations have opened any project within the multiproject.
Open the individual subproject (the specific AS project containing the locked chart) directly, bypassing the multiproject root.
Select File -> Save As...
In the Save Project As dialog:
* Select the checkbox With Reorganization (Slow).
* Provide a new temporary folder path on the local drive.
* Click OK and wait for the reorganization process to complete.
The reorganization process parses every database record, cleans deleted flags, strips orphaned lock records, and reorganizes block tables.
Open the reorganized project, verify that the locked chart opens cleanly, and then reintegrate the subproject into the master multiproject (Multiproject -> Insert into Multiproject).

Multi-User Operational Best Practices

To prevent recurring lockouts in distributed PCS 7 engineering teams, enforce the following plant protocols:

Explicit Check-Out and Notification: Maintain a central engineering log or communicate actively before opening charts online in operational AS projects.
Avoid Long-Term Online Monitoring: Do not leave CFC charts in Test Mode (Debug -> Test Mode) unattended. Close Test Mode immediately after completing functional tuning.
Remove AS from Multiproject for Heavy Editing: When an engineer needs to execute substantial restructuring or large-scale commissioning on an AS, remove that specific AS project from the multiproject (Multiproject -> Remove from Multiproject), copy it locally to the engineering station, complete the work, and re-insert it.
Synchronize Software Updates: Ensure every ES connected to the plant bus runs the exact same PCS 7 version, service pack, and CFC hotfix level.

Verification

Verify the successful restoration of multi-user access across the engineering network:

Primary ES Verification:
* Open the master multiproject on the primary ES.
* Navigate to the previously locked CFC chart and double-click to open it.
* Verify that the chart opens in full Read/Write mode without warning prompts.
* Make a minor cosmetic edit (e.g., move a block or adjust a parameter value), save the chart, and verify clean save completion.
Secondary ES Verification:
* On the secondary ES, open a different CFC chart within the same AS.
* Confirm that both engineering stations can work simultaneously on distinct charts.
Compilation and Download Check:
* Execute a test compilation (Charts -> Compile -> Changes Only).
* Perform a test change download to verify that communication handles to the automation station are fully functional.

Limitations and Operational Precautions

Never Delete Unknown DBF Files: Do not manually delete .dbf or .cdx files from the project folder in an attempt to clear locks. Doing so permanently destroys the project database structure.
Concurrent Download Prohibition: Multi-user engineering does not permit two stations to download to the same automation station simultaneously. Download operations lock the entire AS folder until completion.
Hardware Configuration Exclusivity: HW Config cannot be edited concurrently. Opening HW Config places an exclusive lock on the entire station configuration.
Network Latency Impact: High-latency network connections (such as VPN or remote Wi-Fi links) dramatically increase the probability of SMB lock timeouts and chart lockouts. Engineering over WAN should always utilize remote desktop sessions on a local ES rather than direct network shares.

Engineer FAQ

Why does PCS 7 say a chart is open when the secondary computer has already been rebooted?
When a client computer reboots abruptly, the Windows file server hosting the project files retains open SMB handles until network timeouts expire, and project database records still flag the active editing session.
Can two engineers edit different CFC charts in the same AS project at the same time?
Yes, PCS 7 multi-user engineering allows concurrent editing of distinct CFC charts within the same automation station.
What specific CFC update resolves multi-user chart locking issues in PCS 7 V9.0 SP3?
Installing the latest cumulative update for CFC V9.0 SP3 (Upd1 or higher) resolves known defects where the editor failed to release multi-user synchronization locks upon closing.
How does 'Save As with Reorganization (Slow)' clear locked charts?
The slow reorganization copies only valid, active database records into a fresh database container, stripping out orphaned lock records and corrupted index tables.
Can I remove an AS project from the multiproject to bypass a locked chart?
Yes, you can remove the AS project from the multiproject structure, open it as a stand-alone single project, perform the unlock and reorganization, and then re-insert it.
What Windows permissions are required on the multiproject network share for multi-user engineering?
All participating engineers must have Full Control permissions on both Windows Share and NTFS levels, and belong to the SIMATIC HMI and local Administrators groups.
Will closing a locked file in compmgmt.msc cause data corruption?
Closing an SMB handle can cause data loss if the client is actively writing. If the client machine is closed or rebooted, closing the handle is safe.
Why does going online in Test Mode create an exclusive lock on a CFC chart?
Online Test Mode establishes a dynamic monitoring connection that binds to CPU buffer resources and prevents other engineering stations from downloading structural changes.
How can I tell which engineer is currently locking a specific CFC chart?
In newer PCS 7 versions, the lock dialog displays the computer name and user holding the lock, or check Computer Management -> Shared Folders -> Open Files on the host server.
Does SIMATIC Version Trail help prevent multi-user chart locking conflicts?
SIMATIC Version Trail tracks changes and archives versions, but implementing strict check-out procedures alongside Version Trail minimizes conflicts.

Technical References

Siemens Industry Online Support (SIOS) Portal: What should you watch out for in multi-user engineering in PCS 7? (Entry ID: 22258957).
SIMATIC PCS 7 Engineering System Manual (V9.0 SP3 / V9.1), Siemens AG.
SIMATIC CFC for S7 / PCS 7 Programming Manual, Siemens AG.

Related Tags

PCS 7, CFC, Multi-User Engineering, STEP 7, Engineering Station, File Lock, Troubleshooting, Automation Station

Resolving Multi-User Engineering Chart Lockouts and Access Conflicts in SIMATIC PCS 7