C135 PCS 7 (PCS7)
6C
6 Cielo Ciencia y Tecnología
·Publicada en C135 PCS 7 (PCS7)

Sourcing Superseded CFC Updates and Resolving SFC Compilation Error 1739-20 in SIMATIC PCS 7

Sourcing Superseded CFC Updates and Resolving SFC Compilation Error 1739-20 in SIMATIC PCS 7

SFC compilation error 1739:20 occurs in SIMATIC PCS 7 when internal chart pointers or cross-reference tables between Continuous Function Charts (CFC) and Sequential Function Charts (SFC) lose database consistency. While historical hotfixes like CFC V8.2 Update 3 specifically addressed this compiler defect, intermediate updates are routinely removed from public Siemens support portals once consolidated into cumulative service packs. To resolve compilation error 1739:20 and maintain plant compliance, engineers must install the latest cumulative CFC service pack, execute a complete chart reorganization, or request archived hotfixes directly through an official Siemens technical support contract.

Table of Contents

Root Cause Analysis of SFC Compilation Error 1739-20

During program compilation in SIMATIC PCS 7 (Charts -> Compile -> Chart as Program), the compiler parses all CFC block interconnections, executes block driver generation, and builds execution sequences for Sequential Function Charts (SFC). Error 1739:20 manifests with the specific diagnostic message:

Error 1739:20: SFC chart does not exist (any longer). Compilation aborted.

This failure occurs even when the referenced SFC chart is clearly visible, accessible, and intact within the plant hierarchy. The underlying causes include:

  1. Orphaned Cross-Reference Pointers: When an SFC instance is renamed, copied, or reconnected to CFC block pins, the internal database (s7asr.dbf / s7amx.dbf) fails to update the cross-reference index, causing the compiler to search for a deleted chart ID.
  2. CFC Compiler Regression in Base Releases: Early releases of CFC V8.2 and V8.2 Upd1 contained a known internal memory index bug during full compilation, where nested SFC types triggered pointer corruption.
  3. Partial Compilations Across Multi-User Sessions: Concurrent edits performed across distributed engineering stations can desynchronize chart symbol tables if changes were not compiled sequentially.

Lifecycle of Siemens Software Updates and Dead Links

Engineers frequently encounter dead links on Siemens Industry Online Support (SIOS) when searching for specific patch levels (such as CFC V8.2 + Upd3). Understanding the Siemens software maintenance lifecycle clarifies why these files disappear:

  • Cumulative Maintenance Policy: Siemens updates for CFC, SFC, and STEP 7 are strictly cumulative. Every update contains all bug fixes, security patches, and functional improvements released in preceding updates.
  • Consolidation into Service Packs: When an intermediate update (e.g., Upd3) is superseded by a subsequent Service Pack (e.g., CFC V8.2 SP1) or higher Update (e.g., Upd4 or Upd5), Siemens archives or unpublishes the intermediate link to prevent users from installing obsolete code.
  • Validation Requirements in Regulated Plants: In pharmaceutical (FDA 21 CFR Part 11) or nuclear facilities, plant validation master plans often mandate installing the exact hotfix version qualified during site acceptance testing.

Step-by-Step Procedure to Resolve Error 1739-20

Follow this standardized workflow to eliminate compiler error 1739:20:

Step 1: Install the Latest Cumulative CFC Package

  1. Instead of searching for defunct links to Upd3, navigate to the active SIOS download entry for CFC V8.2 Service Pack 1 (or the latest cumulative update available for your PCS 7 release).
  2. Download the update archive (e.g., SIMATIC_CFC_V82_SP1.zip).
  3. Close all SIMATIC Manager applications, run reset_wincc.vbs to clear handles, and execute Setup.exe as administrator.
  4. Restart the Engineering Station once the update installation concludes.

Step 2: Clear Local Chart Cache

  1. Open SIMATIC Manager.
  2. In the component view, navigate to the affected AS subproject's Charts container.
  3. Open the SFC chart cited in the compilation log.
  4. Select Chart -> Check Consistency. Review the consistency log for missing block type pins or unlinked step/transition conditions.
  5. Save the SFC chart and close the editor.

Step 3: Execute Full Recompilation

  1. Select the Charts folder in the tree view.
  2. Select Charts -> Compile -> Chart as Program...
  3. Under Scope, explicitly select Entire program (do not select Changes only).
  4. Check Generate module drivers.
  5. Click OK to execute a full compilation. Verify that compiler error 1739:20 no longer appears.

Sourcing Archived and Superseded Hotfixes

If regulatory change-control strictly prohibits upgrading to CFC V8.2 SP1 and requires the exact legacy CFC V8.2 Upd3 package:

  1. Create a Siemens Support Request:
    * Navigate to the SIOS portal (support.industry.siemens.com).
    * Click mySupport -> Support Request -> Create Request.
  2. Specify Technical Context:
    * Product: SIMATIC PCS 7 CFC V8.2.
    * State that compiler error 1739:20 has impacted a validated facility.
    * Explicitly request the archived download link or secure file transfer for CFC V8.2 Upd3.
  3. Service Contracts:
    * For software versions that have reached Phased-Out or End of Life status, Siemens requires a valid Software Update Service (SUS) agreement or a Legacy Support Contract to release archived intermediate hotfixes.

Database Cleanup and Full Chart Recompilation

If installing the update does not immediately clear error 1739:20, the project database must be purged of orphaned object records:

  1. Close all open charts across all engineering stations.
  2. In SIMATIC Manager, select File -> Save As...
  3. Choose the target folder path, check With Reorganization (Slow), and click OK.
  4. Once reorganization finishes, open the newly saved project.
  5. Navigate to the chart folder, right-click, and select Charts -> Compile -> Chart as Program (Scope: Entire program).
  6. The reorganization strips out dead table pointers, enabling the compiler to rebuild the chart symbol dictionary cleanly.

Verification

Confirm compiler resolution and controller execution readiness:

  1. Zero Compiler Errors: Confirm that the compilation log finishes with 0 Errors and that output S7 machine code blocks (OB, FB, FC, DB) are compiled successfully into the offline block folder.
  2. S7-PLCSIM Delta Download Test:
    * Open S7-PLCSIM.
    * Download the newly compiled program to the virtual controller.
    * Switch PLCSIM to RUN-P.
    * Verify that the SFC chart transitions through steps normally without runtime fault alarms.
  3. Target Controller Download: Download changes to the plant controller during an authorized engineering maintenance window.

Limitations and Operational Precautions

  • Never Mix CFC and STEP 7 Version Levels: Installing a CFC update while leaving underlying STEP 7 or TH packages outdated can introduce structural library mismatches. Always review the Siemens Compatibility Tool before applying updates.
  • Full Compilation Generates AS Stop Warning on Download: Performing a full compilation ("Entire program") generates a fresh program signature. If structural changes occurred, downloading to the target controller may require an AS STOP. Always verify whether a delta download remains possible before committing changes in a running plant.
  • Backup Before Reorganization: Always create a full multiproject archive (File -> Archive) before executing "Save As with Reorganization (Slow)".
  • Obsolete OS Compiles: Resolving an SFC compiler issue alters internal DB addresses for SFC instances. A subsequent OS Compile is mandatory to synchronize WinCC tag tables and faceplate connections.

Engineer FAQ

  • Why does the CFC compiler say 'SFC chart does not exist' when the chart is open on my screen?
    The internal project database has an orphaned cross-reference pointer that points to a non-existent chart ID or outdated symbol table entry, resolved by installing cumulative CFC updates and reorganizing the project.
  • Are Siemens CFC updates cumulative?
    Yes, all Siemens CFC updates and service packs are strictly cumulative, meaning CFC V8.2 SP1 contains all fixes previously released in CFC V8.2 Upd1, Upd2, and Upd3.
  • Can I download CFC V8.2 Upd3 from third-party automation forums?
    Downloading industrial automation software patches from unauthorized third-party sources poses severe cybersecurity, malware, and plant integrity risks. Always obtain software directly from Siemens SIOS or official Technical Support.
  • What is the meaning of compiler code 1739:20?
    Error 1739:20 is an internal PCS 7 compilation abort code indicating that the chart management subsystem encountered an unresolvable reference to a missing or deregistered SFC object during code generation.
  • How does 'Save As with Reorganization (Slow)' fix compilation errors?
    It creates a brand new database structure, sequentially copying only valid, active chart elements while discarding dead reference pointers, orphaned blocks, and corrupted index tables.
  • Does installing a CFC update require updating the OS server software?
    Usually no, but if the CFC update modifies AS-OS data transfer schemas or Faceplate Designer interfaces, corresponding library updates may also be recommended.
  • Why does Siemens unpublish older update links on SIOS?
    Siemens removes superseded hotfix links to prevent customers from installing intermediate releases that have been replaced by more stable, comprehensive cumulative service packs.
  • What should I do if a full compilation forces an AS STOP on a running plant?
    If you cannot afford a controller shutdown, test compilation on a copy of the project in S7-PLCSIM to determine which specific change invalidated the online delta download buffer.
  • How do I check my current installed CFC hotfix level?
    In SIMATIC Manager, select Help -> About... -> Installed Software, locate CFC, and inspect the exact version, Service Pack, and Update number listed in the table.
  • Is a software contract required to open a Siemens Support Request for older versions?
    Standard product support is free for actively maintained versions, but legacy support contracts or Software Update Service agreements may be required to request archived hotfixes for phased-out versions.

Technical References

  • Siemens Industry Online Support (SIOS) Portal: CFC for SIMATIC S7 / PCS 7 Compilation and Update Guidelines (Entry ID: 109743096).
  • SIMATIC PCS 7 SFC for S7 Programming Manual, Siemens AG.
  • SIMATIC CFC for S7 / PCS 7 Manual, Siemens AG.

Related Articles

Related Tags

PCS 7, CFC, SFC, Compilation Error, Error 1739, Software Updates, SIOS, Troubleshooting

20 respuestas